Spherical law of cosines

Percentage Accurate: 74.2% → 94.1%
Time: 14.4s
Alternatives: 27
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (*
  (acos
   (+
    (* (sin phi1) (sin phi2))
    (* (* (cos phi1) (cos phi2)) (cos (- lambda1 lambda2)))))
  R))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	return acos(((sin(phi1) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * R;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(r, lambda1, lambda2, phi1, phi2)
use fmin_fmax_functions
    real(8), intent (in) :: r
    real(8), intent (in) :: lambda1
    real(8), intent (in) :: lambda2
    real(8), intent (in) :: phi1
    real(8), intent (in) :: phi2
    code = acos(((sin(phi1) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * r
end function
public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	return Math.acos(((Math.sin(phi1) * Math.sin(phi2)) + ((Math.cos(phi1) * Math.cos(phi2)) * Math.cos((lambda1 - lambda2))))) * R;
}
def code(R, lambda1, lambda2, phi1, phi2):
	return math.acos(((math.sin(phi1) * math.sin(phi2)) + ((math.cos(phi1) * math.cos(phi2)) * math.cos((lambda1 - lambda2))))) * R
function code(R, lambda1, lambda2, phi1, phi2)
	return Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(Float64(cos(phi1) * cos(phi2)) * cos(Float64(lambda1 - lambda2))))) * R)
end
function tmp = code(R, lambda1, lambda2, phi1, phi2)
	tmp = acos(((sin(phi1) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * R;
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R
\end{array}

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 27 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 74.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (*
  (acos
   (+
    (* (sin phi1) (sin phi2))
    (* (* (cos phi1) (cos phi2)) (cos (- lambda1 lambda2)))))
  R))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	return acos(((sin(phi1) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * R;
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(r, lambda1, lambda2, phi1, phi2)
use fmin_fmax_functions
    real(8), intent (in) :: r
    real(8), intent (in) :: lambda1
    real(8), intent (in) :: lambda2
    real(8), intent (in) :: phi1
    real(8), intent (in) :: phi2
    code = acos(((sin(phi1) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * r
end function
public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	return Math.acos(((Math.sin(phi1) * Math.sin(phi2)) + ((Math.cos(phi1) * Math.cos(phi2)) * Math.cos((lambda1 - lambda2))))) * R;
}
def code(R, lambda1, lambda2, phi1, phi2):
	return math.acos(((math.sin(phi1) * math.sin(phi2)) + ((math.cos(phi1) * math.cos(phi2)) * math.cos((lambda1 - lambda2))))) * R
function code(R, lambda1, lambda2, phi1, phi2)
	return Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(Float64(cos(phi1) * cos(phi2)) * cos(Float64(lambda1 - lambda2))))) * R)
end
function tmp = code(R, lambda1, lambda2, phi1, phi2)
	tmp = acos(((sin(phi1) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * R;
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R
\end{array}

Alternative 1: 94.1% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \phi_2 \cdot \cos \phi_1\\ \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \mathsf{fma}\left(t\_0, \cos \lambda_2 \cdot \cos \lambda_1, t\_0 \cdot \left(\sin \lambda_2 \cdot \sin \lambda_1\right)\right)\right) \cdot R \end{array} \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (let* ((t_0 (* (cos phi2) (cos phi1))))
   (*
    (acos
     (+
      (* (sin phi1) (sin phi2))
      (fma
       t_0
       (* (cos lambda2) (cos lambda1))
       (* t_0 (* (sin lambda2) (sin lambda1))))))
    R)))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	double t_0 = cos(phi2) * cos(phi1);
	return acos(((sin(phi1) * sin(phi2)) + fma(t_0, (cos(lambda2) * cos(lambda1)), (t_0 * (sin(lambda2) * sin(lambda1)))))) * R;
}
function code(R, lambda1, lambda2, phi1, phi2)
	t_0 = Float64(cos(phi2) * cos(phi1))
	return Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + fma(t_0, Float64(cos(lambda2) * cos(lambda1)), Float64(t_0 * Float64(sin(lambda2) * sin(lambda1)))))) * R)
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Cos[phi2], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]}, N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(t$95$0 * N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[lambda1], $MachinePrecision]), $MachinePrecision] + N[(t$95$0 * N[(N[Sin[lambda2], $MachinePrecision] * N[Sin[lambda1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \phi_2 \cdot \cos \phi_1\\
\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \mathsf{fma}\left(t\_0, \cos \lambda_2 \cdot \cos \lambda_1, t\_0 \cdot \left(\sin \lambda_2 \cdot \sin \lambda_1\right)\right)\right) \cdot R
\end{array}
\end{array}
Derivation
  1. Initial program 74.2%

    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
  2. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    2. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    3. cos-diffN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. cos-negN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    5. lower-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    6. lower-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    7. cos-negN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    8. lower-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    9. lower-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
    10. lower-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
    11. lower-sin.f6494.1

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
  3. Applied rewrites94.1%

    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
  4. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    2. lift-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right)} \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    3. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\color{blue}{\cos \phi_1} \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    4. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    5. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    6. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    7. lift-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    8. lift-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
    9. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
    10. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    11. distribute-lft-inN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\left(\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2\right) + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)}\right) \cdot R \]
    12. lower-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\mathsf{fma}\left(\cos \phi_1 \cdot \cos \phi_2, \cos \lambda_1 \cdot \cos \lambda_2, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)}\right) \cdot R \]
  5. Applied rewrites94.1%

    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2 \cdot \cos \lambda_1, \left(\cos \phi_2 \cdot \cos \phi_1\right) \cdot \left(\sin \lambda_2 \cdot \sin \lambda_1\right)\right)}\right) \cdot R \]
  6. Add Preprocessing

Alternative 2: 94.1% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \cos \lambda_1\right)\right) \cdot R \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (*
  (acos
   (+
    (* (sin phi1) (sin phi2))
    (*
     (* (cos phi1) (cos phi2))
     (fma (sin lambda2) (sin lambda1) (* (cos lambda2) (cos lambda1))))))
  R))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	return acos(((sin(phi1) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * fma(sin(lambda2), sin(lambda1), (cos(lambda2) * cos(lambda1)))))) * R;
}
function code(R, lambda1, lambda2, phi1, phi2)
	return Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(Float64(cos(phi1) * cos(phi2)) * fma(sin(lambda2), sin(lambda1), Float64(cos(lambda2) * cos(lambda1)))))) * R)
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[(N[Sin[lambda2], $MachinePrecision] * N[Sin[lambda1], $MachinePrecision] + N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[lambda1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \cos \lambda_1\right)\right) \cdot R
\end{array}
Derivation
  1. Initial program 74.2%

    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
  2. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    2. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    3. cos-diffN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. cos-negN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    5. lower-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    6. lower-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    7. cos-negN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    8. lower-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    9. lower-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
    10. lower-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
    11. lower-sin.f6494.1

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
  3. Applied rewrites94.1%

    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
  4. Step-by-step derivation
    1. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    2. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    3. lift-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. lift-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
    5. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
    6. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    7. +-commutativeN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\sin \lambda_1 \cdot \sin \lambda_2 + \cos \lambda_1 \cdot \cos \lambda_2\right)}\right) \cdot R \]
    8. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\color{blue}{\sin \lambda_2 \cdot \sin \lambda_1} + \cos \lambda_1 \cdot \cos \lambda_2\right)\right) \cdot R \]
    9. lower-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_1 \cdot \cos \lambda_2\right)}\right) \cdot R \]
    10. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\sin \lambda_2}, \sin \lambda_1, \cos \lambda_1 \cdot \cos \lambda_2\right)\right) \cdot R \]
    11. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \color{blue}{\sin \lambda_1}, \cos \lambda_1 \cdot \cos \lambda_2\right)\right) \cdot R \]
    12. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \color{blue}{\cos \lambda_2 \cdot \cos \lambda_1}\right)\right) \cdot R \]
    13. lower-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \color{blue}{\cos \lambda_2 \cdot \cos \lambda_1}\right)\right) \cdot R \]
    14. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \color{blue}{\cos \lambda_2} \cdot \cos \lambda_1\right)\right) \cdot R \]
    15. lift-cos.f6494.1

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \color{blue}{\cos \lambda_1}\right)\right) \cdot R \]
  5. Applied rewrites94.1%

    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \cos \lambda_1\right)}\right) \cdot R \]
  6. Add Preprocessing

Alternative 3: 94.1% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (*
  (acos
   (+
    (* (sin phi1) (sin phi2))
    (*
     (* (cos phi1) (cos phi2))
     (fma (cos lambda1) (cos lambda2) (* (sin lambda1) (sin lambda2))))))
  R))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	return acos(((sin(phi1) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * fma(cos(lambda1), cos(lambda2), (sin(lambda1) * sin(lambda2)))))) * R;
}
function code(R, lambda1, lambda2, phi1, phi2)
	return Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(Float64(cos(phi1) * cos(phi2)) * fma(cos(lambda1), cos(lambda2), Float64(sin(lambda1) * sin(lambda2)))))) * R)
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[(N[Cos[lambda1], $MachinePrecision] * N[Cos[lambda2], $MachinePrecision] + N[(N[Sin[lambda1], $MachinePrecision] * N[Sin[lambda2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R
\end{array}
Derivation
  1. Initial program 74.2%

    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
  2. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    2. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    3. cos-diffN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. cos-negN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    5. lower-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    6. lower-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    7. cos-negN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    8. lower-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    9. lower-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
    10. lower-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
    11. lower-sin.f6494.1

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
  3. Applied rewrites94.1%

    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
  4. Add Preprocessing

Alternative 4: 83.8% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\\ \mathbf{if}\;\phi_1 \leq -4.1 \cdot 10^{-7}:\\ \;\;\;\;\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, t\_0, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\ \mathbf{elif}\;\phi_1 \leq 1.15 \cdot 10^{-6}:\\ \;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \cos \lambda_1\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, t\_0 \cdot \cos \phi_1\right)\right) \cdot R\\ \end{array} \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (let* ((t_0 (* (cos (- lambda1 lambda2)) (cos phi2))))
   (if (<= phi1 -4.1e-7)
     (* (- (/ PI 2.0) (asin (fma (cos phi1) t_0 (* (sin phi2) (sin phi1))))) R)
     (if (<= phi1 1.15e-6)
       (*
        (acos
         (+
          (* (sin phi1) (sin phi2))
          (*
           (cos phi2)
           (fma (sin lambda2) (sin lambda1) (* (cos lambda2) (cos lambda1))))))
        R)
       (* (acos (fma (sin phi2) (sin phi1) (* t_0 (cos phi1)))) R)))))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	double t_0 = cos((lambda1 - lambda2)) * cos(phi2);
	double tmp;
	if (phi1 <= -4.1e-7) {
		tmp = ((((double) M_PI) / 2.0) - asin(fma(cos(phi1), t_0, (sin(phi2) * sin(phi1))))) * R;
	} else if (phi1 <= 1.15e-6) {
		tmp = acos(((sin(phi1) * sin(phi2)) + (cos(phi2) * fma(sin(lambda2), sin(lambda1), (cos(lambda2) * cos(lambda1)))))) * R;
	} else {
		tmp = acos(fma(sin(phi2), sin(phi1), (t_0 * cos(phi1)))) * R;
	}
	return tmp;
}
function code(R, lambda1, lambda2, phi1, phi2)
	t_0 = Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2))
	tmp = 0.0
	if (phi1 <= -4.1e-7)
		tmp = Float64(Float64(Float64(pi / 2.0) - asin(fma(cos(phi1), t_0, Float64(sin(phi2) * sin(phi1))))) * R);
	elseif (phi1 <= 1.15e-6)
		tmp = Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(cos(phi2) * fma(sin(lambda2), sin(lambda1), Float64(cos(lambda2) * cos(lambda1)))))) * R);
	else
		tmp = Float64(acos(fma(sin(phi2), sin(phi1), Float64(t_0 * cos(phi1)))) * R);
	end
	return tmp
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[phi1, -4.1e-7], N[(N[(N[(Pi / 2.0), $MachinePrecision] - N[ArcSin[N[(N[Cos[phi1], $MachinePrecision] * t$95$0 + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * R), $MachinePrecision], If[LessEqual[phi1, 1.15e-6], N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[Cos[phi2], $MachinePrecision] * N[(N[Sin[lambda2], $MachinePrecision] * N[Sin[lambda1], $MachinePrecision] + N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[lambda1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision] + N[(t$95$0 * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\\
\mathbf{if}\;\phi_1 \leq -4.1 \cdot 10^{-7}:\\
\;\;\;\;\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, t\_0, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\

\mathbf{elif}\;\phi_1 \leq 1.15 \cdot 10^{-6}:\\
\;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \cos \lambda_1\right)\right) \cdot R\\

\mathbf{else}:\\
\;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, t\_0 \cdot \cos \phi_1\right)\right) \cdot R\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if phi1 < -4.0999999999999999e-7

    1. Initial program 78.6%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      3. cos-diffN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      6. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      8. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      9. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      10. lower-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      11. lower-sin.f6499.0

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    3. Applied rewrites99.0%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. Applied rewrites78.5%

      \[\leadsto \color{blue}{\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right)} \cdot R \]

    if -4.0999999999999999e-7 < phi1 < 1.15e-6

    1. Initial program 68.9%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      3. cos-diffN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      6. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      8. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      9. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      10. lower-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      11. lower-sin.f6488.8

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    3. Applied rewrites88.8%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. Step-by-step derivation
      1. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      3. lift-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      5. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      6. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
      7. +-commutativeN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\sin \lambda_1 \cdot \sin \lambda_2 + \cos \lambda_1 \cdot \cos \lambda_2\right)}\right) \cdot R \]
      8. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\color{blue}{\sin \lambda_2 \cdot \sin \lambda_1} + \cos \lambda_1 \cdot \cos \lambda_2\right)\right) \cdot R \]
      9. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_1 \cdot \cos \lambda_2\right)}\right) \cdot R \]
      10. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\sin \lambda_2}, \sin \lambda_1, \cos \lambda_1 \cdot \cos \lambda_2\right)\right) \cdot R \]
      11. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \color{blue}{\sin \lambda_1}, \cos \lambda_1 \cdot \cos \lambda_2\right)\right) \cdot R \]
      12. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \color{blue}{\cos \lambda_2 \cdot \cos \lambda_1}\right)\right) \cdot R \]
      13. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \color{blue}{\cos \lambda_2 \cdot \cos \lambda_1}\right)\right) \cdot R \]
      14. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \color{blue}{\cos \lambda_2} \cdot \cos \lambda_1\right)\right) \cdot R \]
      15. lift-cos.f6488.8

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \color{blue}{\cos \lambda_1}\right)\right) \cdot R \]
    5. Applied rewrites88.8%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \cos \lambda_1\right)}\right) \cdot R \]
    6. Taylor expanded in phi1 around 0

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\cos \phi_2} \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \cos \lambda_1\right)\right) \cdot R \]
    7. Step-by-step derivation
      1. lift-cos.f6488.8

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \cos \lambda_1\right)\right) \cdot R \]
    8. Applied rewrites88.8%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\cos \phi_2} \cdot \mathsf{fma}\left(\sin \lambda_2, \sin \lambda_1, \cos \lambda_2 \cdot \cos \lambda_1\right)\right) \cdot R \]

    if 1.15e-6 < phi1

    1. Initial program 79.7%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift-+.f64N/A

        \[\leadsto \cos^{-1} \color{blue}{\left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
      2. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      3. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      4. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      5. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      6. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      7. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right)} \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      8. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\color{blue}{\cos \phi_1} \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      9. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      10. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      11. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      12. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right)} \cdot R \]
      13. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\sin \phi_2}, \sin \phi_1, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
      14. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \color{blue}{\sin \phi_1}, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
      15. associate-*r*N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\cos \phi_1 \cdot \left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)}\right)\right) \cdot R \]
      16. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot \cos \phi_1}\right)\right) \cdot R \]
      17. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot \cos \phi_1}\right)\right) \cdot R \]
    3. Applied rewrites79.7%

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot \cos \phi_1\right)\right)} \cdot R \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 5: 83.8% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\\ \mathbf{if}\;\phi_1 \leq -4.1 \cdot 10^{-7}:\\ \;\;\;\;\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, t\_0, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\ \mathbf{elif}\;\phi_1 \leq 1.15 \cdot 10^{-6}:\\ \;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, t\_0 \cdot \cos \phi_1\right)\right) \cdot R\\ \end{array} \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (let* ((t_0 (* (cos (- lambda1 lambda2)) (cos phi2))))
   (if (<= phi1 -4.1e-7)
     (* (- (/ PI 2.0) (asin (fma (cos phi1) t_0 (* (sin phi2) (sin phi1))))) R)
     (if (<= phi1 1.15e-6)
       (*
        (acos
         (+
          (* (sin phi1) (sin phi2))
          (*
           (cos phi2)
           (fma (cos lambda1) (cos lambda2) (* (sin lambda1) (sin lambda2))))))
        R)
       (* (acos (fma (sin phi2) (sin phi1) (* t_0 (cos phi1)))) R)))))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	double t_0 = cos((lambda1 - lambda2)) * cos(phi2);
	double tmp;
	if (phi1 <= -4.1e-7) {
		tmp = ((((double) M_PI) / 2.0) - asin(fma(cos(phi1), t_0, (sin(phi2) * sin(phi1))))) * R;
	} else if (phi1 <= 1.15e-6) {
		tmp = acos(((sin(phi1) * sin(phi2)) + (cos(phi2) * fma(cos(lambda1), cos(lambda2), (sin(lambda1) * sin(lambda2)))))) * R;
	} else {
		tmp = acos(fma(sin(phi2), sin(phi1), (t_0 * cos(phi1)))) * R;
	}
	return tmp;
}
function code(R, lambda1, lambda2, phi1, phi2)
	t_0 = Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2))
	tmp = 0.0
	if (phi1 <= -4.1e-7)
		tmp = Float64(Float64(Float64(pi / 2.0) - asin(fma(cos(phi1), t_0, Float64(sin(phi2) * sin(phi1))))) * R);
	elseif (phi1 <= 1.15e-6)
		tmp = Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(cos(phi2) * fma(cos(lambda1), cos(lambda2), Float64(sin(lambda1) * sin(lambda2)))))) * R);
	else
		tmp = Float64(acos(fma(sin(phi2), sin(phi1), Float64(t_0 * cos(phi1)))) * R);
	end
	return tmp
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[phi1, -4.1e-7], N[(N[(N[(Pi / 2.0), $MachinePrecision] - N[ArcSin[N[(N[Cos[phi1], $MachinePrecision] * t$95$0 + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * R), $MachinePrecision], If[LessEqual[phi1, 1.15e-6], N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[Cos[phi2], $MachinePrecision] * N[(N[Cos[lambda1], $MachinePrecision] * N[Cos[lambda2], $MachinePrecision] + N[(N[Sin[lambda1], $MachinePrecision] * N[Sin[lambda2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision] + N[(t$95$0 * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\\
\mathbf{if}\;\phi_1 \leq -4.1 \cdot 10^{-7}:\\
\;\;\;\;\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, t\_0, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\

\mathbf{elif}\;\phi_1 \leq 1.15 \cdot 10^{-6}:\\
\;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R\\

\mathbf{else}:\\
\;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, t\_0 \cdot \cos \phi_1\right)\right) \cdot R\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if phi1 < -4.0999999999999999e-7

    1. Initial program 78.6%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      3. cos-diffN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      6. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      8. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      9. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      10. lower-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      11. lower-sin.f6499.0

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    3. Applied rewrites99.0%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. Applied rewrites78.5%

      \[\leadsto \color{blue}{\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right)} \cdot R \]

    if -4.0999999999999999e-7 < phi1 < 1.15e-6

    1. Initial program 68.9%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      3. cos-diffN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      6. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      8. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      9. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      10. lower-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      11. lower-sin.f6488.8

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    3. Applied rewrites88.8%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. Taylor expanded in phi1 around 0

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\cos \phi_2} \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    5. Step-by-step derivation
      1. lift-cos.f6488.8

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    6. Applied rewrites88.8%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\cos \phi_2} \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]

    if 1.15e-6 < phi1

    1. Initial program 79.7%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift-+.f64N/A

        \[\leadsto \cos^{-1} \color{blue}{\left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
      2. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      3. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      4. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      5. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      6. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      7. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right)} \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      8. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\color{blue}{\cos \phi_1} \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      9. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      10. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      11. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      12. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right)} \cdot R \]
      13. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\sin \phi_2}, \sin \phi_1, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
      14. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \color{blue}{\sin \phi_1}, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
      15. associate-*r*N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\cos \phi_1 \cdot \left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)}\right)\right) \cdot R \]
      16. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot \cos \phi_1}\right)\right) \cdot R \]
      17. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot \cos \phi_1}\right)\right) \cdot R \]
    3. Applied rewrites79.7%

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot \cos \phi_1\right)\right)} \cdot R \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 6: 83.6% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\\ \mathbf{if}\;\phi_1 \leq -2.6 \cdot 10^{-9}:\\ \;\;\;\;\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, t\_0, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\ \mathbf{elif}\;\phi_1 \leq 4.15 \cdot 10^{-10}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, t\_0 \cdot \cos \phi_1\right)\right) \cdot R\\ \end{array} \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (let* ((t_0 (* (cos (- lambda1 lambda2)) (cos phi2))))
   (if (<= phi1 -2.6e-9)
     (* (- (/ PI 2.0) (asin (fma (cos phi1) t_0 (* (sin phi2) (sin phi1))))) R)
     (if (<= phi1 4.15e-10)
       (*
        (acos
         (fma
          (cos lambda1)
          (* (cos lambda2) (cos phi2))
          (* (cos phi2) (* (sin lambda1) (sin lambda2)))))
        R)
       (* (acos (fma (sin phi2) (sin phi1) (* t_0 (cos phi1)))) R)))))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	double t_0 = cos((lambda1 - lambda2)) * cos(phi2);
	double tmp;
	if (phi1 <= -2.6e-9) {
		tmp = ((((double) M_PI) / 2.0) - asin(fma(cos(phi1), t_0, (sin(phi2) * sin(phi1))))) * R;
	} else if (phi1 <= 4.15e-10) {
		tmp = acos(fma(cos(lambda1), (cos(lambda2) * cos(phi2)), (cos(phi2) * (sin(lambda1) * sin(lambda2))))) * R;
	} else {
		tmp = acos(fma(sin(phi2), sin(phi1), (t_0 * cos(phi1)))) * R;
	}
	return tmp;
}
function code(R, lambda1, lambda2, phi1, phi2)
	t_0 = Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2))
	tmp = 0.0
	if (phi1 <= -2.6e-9)
		tmp = Float64(Float64(Float64(pi / 2.0) - asin(fma(cos(phi1), t_0, Float64(sin(phi2) * sin(phi1))))) * R);
	elseif (phi1 <= 4.15e-10)
		tmp = Float64(acos(fma(cos(lambda1), Float64(cos(lambda2) * cos(phi2)), Float64(cos(phi2) * Float64(sin(lambda1) * sin(lambda2))))) * R);
	else
		tmp = Float64(acos(fma(sin(phi2), sin(phi1), Float64(t_0 * cos(phi1)))) * R);
	end
	return tmp
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[phi1, -2.6e-9], N[(N[(N[(Pi / 2.0), $MachinePrecision] - N[ArcSin[N[(N[Cos[phi1], $MachinePrecision] * t$95$0 + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * R), $MachinePrecision], If[LessEqual[phi1, 4.15e-10], N[(N[ArcCos[N[(N[Cos[lambda1], $MachinePrecision] * N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[Cos[phi2], $MachinePrecision] * N[(N[Sin[lambda1], $MachinePrecision] * N[Sin[lambda2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision] + N[(t$95$0 * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\\
\mathbf{if}\;\phi_1 \leq -2.6 \cdot 10^{-9}:\\
\;\;\;\;\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, t\_0, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\

\mathbf{elif}\;\phi_1 \leq 4.15 \cdot 10^{-10}:\\
\;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R\\

\mathbf{else}:\\
\;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, t\_0 \cdot \cos \phi_1\right)\right) \cdot R\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if phi1 < -2.6000000000000001e-9

    1. Initial program 78.5%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      3. cos-diffN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      6. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      8. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      9. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      10. lower-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      11. lower-sin.f6499.0

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    3. Applied rewrites99.0%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. Applied rewrites78.4%

      \[\leadsto \color{blue}{\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right)} \cdot R \]

    if -2.6000000000000001e-9 < phi1 < 4.1500000000000001e-10

    1. Initial program 69.0%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      3. cos-diffN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      6. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      8. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      9. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      10. lower-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      11. lower-sin.f6488.8

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    3. Applied rewrites88.8%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      2. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right)} \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      3. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\color{blue}{\cos \phi_1} \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      4. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      6. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. lift-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      8. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      9. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      10. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
      11. distribute-lft-inN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\left(\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2\right) + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)}\right) \cdot R \]
      12. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\mathsf{fma}\left(\cos \phi_1 \cdot \cos \phi_2, \cos \lambda_1 \cdot \cos \lambda_2, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)}\right) \cdot R \]
    5. Applied rewrites88.8%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2 \cdot \cos \lambda_1, \left(\cos \phi_2 \cdot \cos \phi_1\right) \cdot \left(\sin \lambda_2 \cdot \sin \lambda_1\right)\right)}\right) \cdot R \]
    6. Taylor expanded in phi1 around 0

      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \lambda_1 \cdot \left(\cos \lambda_2 \cdot \cos \phi_2\right) + \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)} \cdot R \]
    7. Step-by-step derivation
      1. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2 \cdot \cos \phi_2}, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2} \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      3. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \color{blue}{\cos \phi_2}, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      4. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \color{blue}{\phi_2}, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      5. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      6. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      7. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      8. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      9. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      10. lift-sin.f6488.6

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
    8. Applied rewrites88.6%

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_2, \cos \phi_2 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right)} \cdot R \]

    if 4.1500000000000001e-10 < phi1

    1. Initial program 79.5%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift-+.f64N/A

        \[\leadsto \cos^{-1} \color{blue}{\left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
      2. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      3. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      4. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      5. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      6. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      7. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right)} \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      8. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\color{blue}{\cos \phi_1} \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      9. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      10. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      11. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      12. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right)} \cdot R \]
      13. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\sin \phi_2}, \sin \phi_1, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
      14. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \color{blue}{\sin \phi_1}, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
      15. associate-*r*N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\cos \phi_1 \cdot \left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)}\right)\right) \cdot R \]
      16. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot \cos \phi_1}\right)\right) \cdot R \]
      17. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot \cos \phi_1}\right)\right) \cdot R \]
    3. Applied rewrites79.5%

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot \cos \phi_1\right)\right)} \cdot R \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Alternative 7: 83.5% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\ \mathbf{if}\;\phi_2 \leq -2.45 \cdot 10^{-12}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\phi_2 \leq 3.6 \cdot 10^{-7}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (let* ((t_0
         (*
          (-
           (/ PI 2.0)
           (asin
            (fma
             (cos phi1)
             (* (cos (- lambda1 lambda2)) (cos phi2))
             (* (sin phi2) (sin phi1)))))
          R)))
   (if (<= phi2 -2.45e-12)
     t_0
     (if (<= phi2 3.6e-7)
       (*
        (acos
         (fma
          (cos lambda1)
          (* (cos lambda2) (cos phi1))
          (* (cos phi1) (* (sin lambda1) (sin lambda2)))))
        R)
       t_0))))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	double t_0 = ((((double) M_PI) / 2.0) - asin(fma(cos(phi1), (cos((lambda1 - lambda2)) * cos(phi2)), (sin(phi2) * sin(phi1))))) * R;
	double tmp;
	if (phi2 <= -2.45e-12) {
		tmp = t_0;
	} else if (phi2 <= 3.6e-7) {
		tmp = acos(fma(cos(lambda1), (cos(lambda2) * cos(phi1)), (cos(phi1) * (sin(lambda1) * sin(lambda2))))) * R;
	} else {
		tmp = t_0;
	}
	return tmp;
}
function code(R, lambda1, lambda2, phi1, phi2)
	t_0 = Float64(Float64(Float64(pi / 2.0) - asin(fma(cos(phi1), Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2)), Float64(sin(phi2) * sin(phi1))))) * R)
	tmp = 0.0
	if (phi2 <= -2.45e-12)
		tmp = t_0;
	elseif (phi2 <= 3.6e-7)
		tmp = Float64(acos(fma(cos(lambda1), Float64(cos(lambda2) * cos(phi1)), Float64(cos(phi1) * Float64(sin(lambda1) * sin(lambda2))))) * R);
	else
		tmp = t_0;
	end
	return tmp
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[(N[(Pi / 2.0), $MachinePrecision] - N[ArcSin[N[(N[Cos[phi1], $MachinePrecision] * N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[phi2, -2.45e-12], t$95$0, If[LessEqual[phi2, 3.6e-7], N[(N[ArcCos[N[(N[Cos[lambda1], $MachinePrecision] * N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision] + N[(N[Cos[phi1], $MachinePrecision] * N[(N[Sin[lambda1], $MachinePrecision] * N[Sin[lambda2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], t$95$0]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\
\mathbf{if}\;\phi_2 \leq -2.45 \cdot 10^{-12}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;\phi_2 \leq 3.6 \cdot 10^{-7}:\\
\;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if phi2 < -2.44999999999999986e-12 or 3.59999999999999994e-7 < phi2

    1. Initial program 78.9%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      3. cos-diffN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      6. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      8. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      9. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      10. lower-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      11. lower-sin.f6499.0

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    3. Applied rewrites99.0%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. Applied rewrites78.8%

      \[\leadsto \color{blue}{\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right)} \cdot R \]

    if -2.44999999999999986e-12 < phi2 < 3.59999999999999994e-7

    1. Initial program 69.1%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      3. cos-diffN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      6. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      8. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      9. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      10. lower-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      11. lower-sin.f6488.8

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    3. Applied rewrites88.8%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      2. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right)} \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      3. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\color{blue}{\cos \phi_1} \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      4. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      6. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. lift-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      8. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      9. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      10. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
      11. distribute-lft-inN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\left(\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2\right) + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)}\right) \cdot R \]
      12. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\mathsf{fma}\left(\cos \phi_1 \cdot \cos \phi_2, \cos \lambda_1 \cdot \cos \lambda_2, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)}\right) \cdot R \]
    5. Applied rewrites88.8%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2 \cdot \cos \lambda_1, \left(\cos \phi_2 \cdot \cos \phi_1\right) \cdot \left(\sin \lambda_2 \cdot \sin \lambda_1\right)\right)}\right) \cdot R \]
    6. Taylor expanded in phi2 around 0

      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \lambda_1 \cdot \left(\cos \lambda_2 \cdot \cos \phi_1\right) + \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)} \cdot R \]
    7. Step-by-step derivation
      1. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2 \cdot \cos \phi_1}, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2} \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      3. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \color{blue}{\cos \phi_1}, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      4. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \color{blue}{\phi_1}, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      5. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      6. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      7. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      8. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      9. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
      10. lift-sin.f6488.6

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
    8. Applied rewrites88.6%

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2 \cdot \cos \phi_1, \cos \phi_1 \cdot \left(\sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right)} \cdot R \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 8: 83.5% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\ \mathbf{if}\;\phi_2 \leq -2.45 \cdot 10^{-12}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\phi_2 \leq 3.6 \cdot 10^{-7}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_2 \cdot \sin \lambda_1\right) \cdot \cos \phi_1\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (let* ((t_0
         (*
          (-
           (/ PI 2.0)
           (asin
            (fma
             (cos phi1)
             (* (cos (- lambda1 lambda2)) (cos phi2))
             (* (sin phi2) (sin phi1)))))
          R)))
   (if (<= phi2 -2.45e-12)
     t_0
     (if (<= phi2 3.6e-7)
       (*
        (acos
         (fma
          (* (cos lambda2) (cos lambda1))
          (cos phi1)
          (* (* (sin lambda2) (sin lambda1)) (cos phi1))))
        R)
       t_0))))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	double t_0 = ((((double) M_PI) / 2.0) - asin(fma(cos(phi1), (cos((lambda1 - lambda2)) * cos(phi2)), (sin(phi2) * sin(phi1))))) * R;
	double tmp;
	if (phi2 <= -2.45e-12) {
		tmp = t_0;
	} else if (phi2 <= 3.6e-7) {
		tmp = acos(fma((cos(lambda2) * cos(lambda1)), cos(phi1), ((sin(lambda2) * sin(lambda1)) * cos(phi1)))) * R;
	} else {
		tmp = t_0;
	}
	return tmp;
}
function code(R, lambda1, lambda2, phi1, phi2)
	t_0 = Float64(Float64(Float64(pi / 2.0) - asin(fma(cos(phi1), Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2)), Float64(sin(phi2) * sin(phi1))))) * R)
	tmp = 0.0
	if (phi2 <= -2.45e-12)
		tmp = t_0;
	elseif (phi2 <= 3.6e-7)
		tmp = Float64(acos(fma(Float64(cos(lambda2) * cos(lambda1)), cos(phi1), Float64(Float64(sin(lambda2) * sin(lambda1)) * cos(phi1)))) * R);
	else
		tmp = t_0;
	end
	return tmp
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[(N[(Pi / 2.0), $MachinePrecision] - N[ArcSin[N[(N[Cos[phi1], $MachinePrecision] * N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[phi2, -2.45e-12], t$95$0, If[LessEqual[phi2, 3.6e-7], N[(N[ArcCos[N[(N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[lambda1], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision] + N[(N[(N[Sin[lambda2], $MachinePrecision] * N[Sin[lambda1], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], t$95$0]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R\\
\mathbf{if}\;\phi_2 \leq -2.45 \cdot 10^{-12}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;\phi_2 \leq 3.6 \cdot 10^{-7}:\\
\;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_2 \cdot \sin \lambda_1\right) \cdot \cos \phi_1\right)\right) \cdot R\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if phi2 < -2.44999999999999986e-12 or 3.59999999999999994e-7 < phi2

    1. Initial program 78.9%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      2. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      3. cos-diffN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      4. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
      6. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      7. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      8. lower-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      9. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      10. lower-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
      11. lower-sin.f6499.0

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
    3. Applied rewrites99.0%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. Applied rewrites78.8%

      \[\leadsto \color{blue}{\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right)} \cdot R \]

    if -2.44999999999999986e-12 < phi2 < 3.59999999999999994e-7

    1. Initial program 69.1%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Taylor expanded in phi2 around 0

      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
    3. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
      2. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
      3. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
      4. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
      5. lift-cos.f6468.9

        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
    4. Applied rewrites68.9%

      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
      2. lift--.f64N/A

        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
      3. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
      4. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
      5. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
      6. cos-diff-revN/A

        \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \left(\cos \lambda_1 \cdot \cos \lambda_2 + \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
      7. distribute-rgt-inN/A

        \[\leadsto \cos^{-1} \left(\left(\cos \lambda_1 \cdot \cos \lambda_2\right) \cdot \cos \phi_1 + \color{blue}{\left(\sin \lambda_1 \cdot \sin \lambda_2\right) \cdot \cos \phi_1}\right) \cdot R \]
      8. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1 \cdot \cos \lambda_2, \color{blue}{\cos \phi_1}, \left(\sin \lambda_1 \cdot \sin \lambda_2\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      9. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \color{blue}{\phi_1}, \left(\sin \lambda_1 \cdot \sin \lambda_2\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      10. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \color{blue}{\phi_1}, \left(\sin \lambda_1 \cdot \sin \lambda_2\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      11. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_1 \cdot \sin \lambda_2\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      12. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_1 \cdot \sin \lambda_2\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      13. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_1 \cdot \sin \lambda_2\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      14. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_1 \cdot \sin \lambda_2\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      15. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_2 \cdot \sin \lambda_1\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      16. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_2 \cdot \sin \lambda_1\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      17. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_2 \cdot \sin \lambda_1\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      18. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_2 \cdot \sin \lambda_1\right) \cdot \cos \phi_1\right)\right) \cdot R \]
      19. lift-cos.f6488.6

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \cos \phi_1, \left(\sin \lambda_2 \cdot \sin \lambda_1\right) \cdot \cos \phi_1\right)\right) \cdot R \]
    6. Applied rewrites88.6%

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \lambda_1, \color{blue}{\cos \phi_1}, \left(\sin \lambda_2 \cdot \sin \lambda_1\right) \cdot \cos \phi_1\right)\right) \cdot R \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 9: 74.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (*
  (-
   (/ PI 2.0)
   (asin
    (fma
     (cos phi1)
     (* (cos (- lambda1 lambda2)) (cos phi2))
     (* (sin phi2) (sin phi1)))))
  R))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	return ((((double) M_PI) / 2.0) - asin(fma(cos(phi1), (cos((lambda1 - lambda2)) * cos(phi2)), (sin(phi2) * sin(phi1))))) * R;
}
function code(R, lambda1, lambda2, phi1, phi2)
	return Float64(Float64(Float64(pi / 2.0) - asin(fma(cos(phi1), Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2)), Float64(sin(phi2) * sin(phi1))))) * R)
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[(N[(Pi / 2.0), $MachinePrecision] - N[ArcSin[N[(N[Cos[phi1], $MachinePrecision] * N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * R), $MachinePrecision]
\begin{array}{l}

\\
\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right) \cdot R
\end{array}
Derivation
  1. Initial program 74.2%

    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
  2. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    2. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    3. cos-diffN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\left(\cos \lambda_1 \cdot \cos \lambda_2 + \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    4. cos-negN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\cos \lambda_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)} + \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    5. lower-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
    6. lower-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\color{blue}{\cos \lambda_1}, \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    7. cos-negN/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    8. lower-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \lambda_2}, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    9. lower-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1 \cdot \sin \lambda_2}\right)\right) \cdot R \]
    10. lower-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right) \cdot R \]
    11. lower-sin.f6494.1

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
  3. Applied rewrites94.1%

    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right) \cdot R \]
  4. Applied rewrites74.1%

    \[\leadsto \color{blue}{\left(\frac{\pi}{2} - \sin^{-1} \left(\mathsf{fma}\left(\cos \phi_1, \cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)\right)} \cdot R \]
  5. Add Preprocessing

Alternative 10: 74.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot \cos \phi_1\right)\right) \cdot R \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (*
  (acos
   (fma
    (sin phi2)
    (sin phi1)
    (* (* (cos (- lambda1 lambda2)) (cos phi2)) (cos phi1))))
  R))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	return acos(fma(sin(phi2), sin(phi1), ((cos((lambda1 - lambda2)) * cos(phi2)) * cos(phi1)))) * R;
}
function code(R, lambda1, lambda2, phi1, phi2)
	return Float64(acos(fma(sin(phi2), sin(phi1), Float64(Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2)) * cos(phi1)))) * R)
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision] + N[(N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot \cos \phi_1\right)\right) \cdot R
\end{array}
Derivation
  1. Initial program 74.2%

    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
  2. Step-by-step derivation
    1. lift-+.f64N/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
    2. lift-*.f64N/A

      \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    3. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    4. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    5. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    6. lift-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    7. lift-*.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right)} \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    8. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\color{blue}{\cos \phi_1} \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    9. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    10. lift--.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    11. lift-cos.f64N/A

      \[\leadsto \cos^{-1} \left(\sin \phi_2 \cdot \sin \phi_1 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\lambda_1 - \lambda_2\right)}\right) \cdot R \]
    12. lower-fma.f64N/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right)} \cdot R \]
    13. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\sin \phi_2}, \sin \phi_1, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
    14. lift-sin.f64N/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \color{blue}{\sin \phi_1}, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
    15. associate-*r*N/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\cos \phi_1 \cdot \left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)}\right)\right) \cdot R \]
    16. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot \cos \phi_1}\right)\right) \cdot R \]
    17. lower-*.f64N/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot \cos \phi_1}\right)\right) \cdot R \]
  3. Applied rewrites74.2%

    \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot \cos \phi_1\right)\right)} \cdot R \]
  4. Add Preprocessing

Alternative 11: 74.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sin \phi_2 \cdot \sin \phi_1\\ \mathbf{if}\;\lambda_2 \leq -0.000118:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, t\_0\right)\right) \cdot R\\ \mathbf{elif}\;\lambda_2 \leq 3.3 \cdot 10^{-6}:\\ \;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, t\_0\right)\right) \cdot R\\ \end{array} \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (let* ((t_0 (* (sin phi2) (sin phi1))))
   (if (<= lambda2 -0.000118)
     (* (acos (fma (* (cos phi2) (cos phi1)) (cos lambda2) t_0)) R)
     (if (<= lambda2 3.3e-6)
       (*
        (acos
         (+
          (* (sin phi1) (sin phi2))
          (* (* (cos phi1) (cos phi2)) (cos lambda1))))
        R)
       (* (acos (fma (* (cos lambda2) (cos phi2)) (cos phi1) t_0)) R)))))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	double t_0 = sin(phi2) * sin(phi1);
	double tmp;
	if (lambda2 <= -0.000118) {
		tmp = acos(fma((cos(phi2) * cos(phi1)), cos(lambda2), t_0)) * R;
	} else if (lambda2 <= 3.3e-6) {
		tmp = acos(((sin(phi1) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * cos(lambda1)))) * R;
	} else {
		tmp = acos(fma((cos(lambda2) * cos(phi2)), cos(phi1), t_0)) * R;
	}
	return tmp;
}
function code(R, lambda1, lambda2, phi1, phi2)
	t_0 = Float64(sin(phi2) * sin(phi1))
	tmp = 0.0
	if (lambda2 <= -0.000118)
		tmp = Float64(acos(fma(Float64(cos(phi2) * cos(phi1)), cos(lambda2), t_0)) * R);
	elseif (lambda2 <= 3.3e-6)
		tmp = Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(Float64(cos(phi1) * cos(phi2)) * cos(lambda1)))) * R);
	else
		tmp = Float64(acos(fma(Float64(cos(lambda2) * cos(phi2)), cos(phi1), t_0)) * R);
	end
	return tmp
end
code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[lambda2, -0.000118], N[(N[ArcCos[N[(N[(N[Cos[phi2], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision] * N[Cos[lambda2], $MachinePrecision] + t$95$0), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], If[LessEqual[lambda2, 3.3e-6], N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[lambda1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision] + t$95$0), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sin \phi_2 \cdot \sin \phi_1\\
\mathbf{if}\;\lambda_2 \leq -0.000118:\\
\;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, t\_0\right)\right) \cdot R\\

\mathbf{elif}\;\lambda_2 \leq 3.3 \cdot 10^{-6}:\\
\;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_1\right) \cdot R\\

\mathbf{else}:\\
\;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, t\_0\right)\right) \cdot R\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if lambda2 < -1.18e-4

    1. Initial program 61.9%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Taylor expanded in lambda1 around 0

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)}\right) \cdot R \]
    3. Step-by-step derivation
      1. cos-negN/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
      2. lower-cos.f6461.7

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
    4. Applied rewrites61.7%

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \lambda_2}\right) \cdot R \]
    5. Step-by-step derivation
      1. lift-+.f64N/A

        \[\leadsto \cos^{-1} \color{blue}{\left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right)} \cdot R \]
      2. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
      3. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
      4. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
      5. +-commutativeN/A

        \[\leadsto \cos^{-1} \color{blue}{\left(\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2 + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
      6. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2} + \sin \phi_1 \cdot \sin \phi_2\right) \cdot R \]
      7. lift-*.f64N/A

        \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right)} \cdot \cos \lambda_2 + \sin \phi_1 \cdot \sin \phi_2\right) \cdot R \]
      8. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\left(\color{blue}{\cos \phi_1} \cdot \cos \phi_2\right) \cdot \cos \lambda_2 + \sin \phi_1 \cdot \sin \phi_2\right) \cdot R \]
      9. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right) \cdot \cos \lambda_2 + \sin \phi_1 \cdot \sin \phi_2\right) \cdot R \]
      10. lower-fma.f64N/A

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \phi_1 \cdot \cos \phi_2, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right)} \cdot R \]
      11. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\cos \phi_2 \cdot \cos \phi_1}, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
      12. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\cos \phi_2 \cdot \cos \phi_1}, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
      13. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\cos \phi_2} \cdot \cos \phi_1, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
      14. lift-cos.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \color{blue}{\cos \phi_1}, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
      15. *-commutativeN/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \color{blue}{\sin \phi_2 \cdot \sin \phi_1}\right)\right) \cdot R \]
      16. lower-*.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \color{blue}{\sin \phi_2 \cdot \sin \phi_1}\right)\right) \cdot R \]
      17. lift-sin.f64N/A

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \color{blue}{\sin \phi_2} \cdot \sin \phi_1\right)\right) \cdot R \]
      18. lift-sin.f6461.7

        \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \sin \phi_2 \cdot \color{blue}{\sin \phi_1}\right)\right) \cdot R \]
    6. Applied rewrites61.7%

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]

    if -1.18e-4 < lambda2 < 3.30000000000000017e-6

    1. Initial program 88.3%

      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
    2. Taylor expanded in lambda1 around inf

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\lambda_1}\right) \cdot R \]
    3. Step-by-step derivation
      1. Applied rewrites88.2%

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \color{blue}{\lambda_1}\right) \cdot R \]

      if 3.30000000000000017e-6 < lambda2

      1. Initial program 59.5%

        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      2. Taylor expanded in lambda1 around 0

        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right)\right) + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
      3. Step-by-step derivation
        1. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right)\right) \cdot \cos \phi_1 + \color{blue}{\sin \phi_1} \cdot \sin \phi_2\right) \cdot R \]
        2. lower-fma.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \color{blue}{\cos \phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        3. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot \cos \phi_2, \cos \color{blue}{\phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        4. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot \cos \phi_2, \cos \color{blue}{\phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        5. cos-negN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        6. lower-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        7. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        8. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        9. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        10. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        11. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        12. lift-sin.f6459.1

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
      4. Applied rewrites59.1%

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]
    4. Recombined 3 regimes into one program.
    5. Add Preprocessing

    Alternative 12: 74.0% accurate, 1.0× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_0 := \sin \phi_2 \cdot \sin \phi_1\\ t_1 := \cos \phi_2 \cdot \cos \phi_1\\ \mathbf{if}\;\lambda_2 \leq -0.000118:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(t\_1, \cos \lambda_2, t\_0\right)\right) \cdot R\\ \mathbf{elif}\;\lambda_2 \leq 3.3 \cdot 10^{-6}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, t\_1, t\_0\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, t\_0\right)\right) \cdot R\\ \end{array} \end{array} \]
    (FPCore (R lambda1 lambda2 phi1 phi2)
     :precision binary64
     (let* ((t_0 (* (sin phi2) (sin phi1))) (t_1 (* (cos phi2) (cos phi1))))
       (if (<= lambda2 -0.000118)
         (* (acos (fma t_1 (cos lambda2) t_0)) R)
         (if (<= lambda2 3.3e-6)
           (* (acos (fma (cos lambda1) t_1 t_0)) R)
           (* (acos (fma (* (cos lambda2) (cos phi2)) (cos phi1) t_0)) R)))))
    double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
    	double t_0 = sin(phi2) * sin(phi1);
    	double t_1 = cos(phi2) * cos(phi1);
    	double tmp;
    	if (lambda2 <= -0.000118) {
    		tmp = acos(fma(t_1, cos(lambda2), t_0)) * R;
    	} else if (lambda2 <= 3.3e-6) {
    		tmp = acos(fma(cos(lambda1), t_1, t_0)) * R;
    	} else {
    		tmp = acos(fma((cos(lambda2) * cos(phi2)), cos(phi1), t_0)) * R;
    	}
    	return tmp;
    }
    
    function code(R, lambda1, lambda2, phi1, phi2)
    	t_0 = Float64(sin(phi2) * sin(phi1))
    	t_1 = Float64(cos(phi2) * cos(phi1))
    	tmp = 0.0
    	if (lambda2 <= -0.000118)
    		tmp = Float64(acos(fma(t_1, cos(lambda2), t_0)) * R);
    	elseif (lambda2 <= 3.3e-6)
    		tmp = Float64(acos(fma(cos(lambda1), t_1, t_0)) * R);
    	else
    		tmp = Float64(acos(fma(Float64(cos(lambda2) * cos(phi2)), cos(phi1), t_0)) * R);
    	end
    	return tmp
    end
    
    code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[Cos[phi2], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[lambda2, -0.000118], N[(N[ArcCos[N[(t$95$1 * N[Cos[lambda2], $MachinePrecision] + t$95$0), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], If[LessEqual[lambda2, 3.3e-6], N[(N[ArcCos[N[(N[Cos[lambda1], $MachinePrecision] * t$95$1 + t$95$0), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision] + t$95$0), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_0 := \sin \phi_2 \cdot \sin \phi_1\\
    t_1 := \cos \phi_2 \cdot \cos \phi_1\\
    \mathbf{if}\;\lambda_2 \leq -0.000118:\\
    \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(t\_1, \cos \lambda_2, t\_0\right)\right) \cdot R\\
    
    \mathbf{elif}\;\lambda_2 \leq 3.3 \cdot 10^{-6}:\\
    \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, t\_1, t\_0\right)\right) \cdot R\\
    
    \mathbf{else}:\\
    \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, t\_0\right)\right) \cdot R\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 3 regimes
    2. if lambda2 < -1.18e-4

      1. Initial program 61.9%

        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      2. Taylor expanded in lambda1 around 0

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)}\right) \cdot R \]
      3. Step-by-step derivation
        1. cos-negN/A

          \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
        2. lower-cos.f6461.7

          \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
      4. Applied rewrites61.7%

        \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \lambda_2}\right) \cdot R \]
      5. Step-by-step derivation
        1. lift-+.f64N/A

          \[\leadsto \cos^{-1} \color{blue}{\left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right)} \cdot R \]
        2. lift-*.f64N/A

          \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
        3. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
        4. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
        5. +-commutativeN/A

          \[\leadsto \cos^{-1} \color{blue}{\left(\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2 + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
        6. lift-*.f64N/A

          \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2} + \sin \phi_1 \cdot \sin \phi_2\right) \cdot R \]
        7. lift-*.f64N/A

          \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 \cdot \cos \phi_2\right)} \cdot \cos \lambda_2 + \sin \phi_1 \cdot \sin \phi_2\right) \cdot R \]
        8. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\color{blue}{\cos \phi_1} \cdot \cos \phi_2\right) \cdot \cos \lambda_2 + \sin \phi_1 \cdot \sin \phi_2\right) \cdot R \]
        9. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right) \cdot \cos \lambda_2 + \sin \phi_1 \cdot \sin \phi_2\right) \cdot R \]
        10. lower-fma.f64N/A

          \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \phi_1 \cdot \cos \phi_2, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right)} \cdot R \]
        11. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\cos \phi_2 \cdot \cos \phi_1}, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        12. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\cos \phi_2 \cdot \cos \phi_1}, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        13. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\cos \phi_2} \cdot \cos \phi_1, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        14. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \color{blue}{\cos \phi_1}, \cos \lambda_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        15. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \color{blue}{\sin \phi_2 \cdot \sin \phi_1}\right)\right) \cdot R \]
        16. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \color{blue}{\sin \phi_2 \cdot \sin \phi_1}\right)\right) \cdot R \]
        17. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \color{blue}{\sin \phi_2} \cdot \sin \phi_1\right)\right) \cdot R \]
        18. lift-sin.f6461.7

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \sin \phi_2 \cdot \color{blue}{\sin \phi_1}\right)\right) \cdot R \]
      6. Applied rewrites61.7%

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \phi_1, \cos \lambda_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]

      if -1.18e-4 < lambda2 < 3.30000000000000017e-6

      1. Initial program 88.3%

        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      2. Taylor expanded in lambda2 around 0

        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \lambda_1 \cdot \left(\cos \phi_1 \cdot \cos \phi_2\right) + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
      3. Step-by-step derivation
        1. lower-fma.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \phi_1 \cdot \cos \phi_2}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        2. lower-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \phi_1} \cdot \cos \phi_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        3. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \color{blue}{\cos \phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        4. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \color{blue}{\cos \phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        5. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \color{blue}{\phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        6. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        7. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        8. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        9. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        10. lift-sin.f6488.2

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
      4. Applied rewrites88.2%

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]

      if 3.30000000000000017e-6 < lambda2

      1. Initial program 59.5%

        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      2. Taylor expanded in lambda1 around 0

        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right)\right) + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
      3. Step-by-step derivation
        1. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right)\right) \cdot \cos \phi_1 + \color{blue}{\sin \phi_1} \cdot \sin \phi_2\right) \cdot R \]
        2. lower-fma.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \color{blue}{\cos \phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        3. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot \cos \phi_2, \cos \color{blue}{\phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        4. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot \cos \phi_2, \cos \color{blue}{\phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        5. cos-negN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        6. lower-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        7. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        8. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        9. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        10. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        11. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        12. lift-sin.f6459.1

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
      4. Applied rewrites59.1%

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]
    3. Recombined 3 regimes into one program.
    4. Add Preprocessing

    Alternative 13: 74.0% accurate, 1.0× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_0 := \sin \phi_2 \cdot \sin \phi_1\\ t_1 := \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, t\_0\right)\right) \cdot R\\ \mathbf{if}\;\lambda_2 \leq -0.000118:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;\lambda_2 \leq 3.3 \cdot 10^{-6}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, t\_0\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
    (FPCore (R lambda1 lambda2 phi1 phi2)
     :precision binary64
     (let* ((t_0 (* (sin phi2) (sin phi1)))
            (t_1 (* (acos (fma (* (cos lambda2) (cos phi2)) (cos phi1) t_0)) R)))
       (if (<= lambda2 -0.000118)
         t_1
         (if (<= lambda2 3.3e-6)
           (* (acos (fma (cos lambda1) (* (cos phi2) (cos phi1)) t_0)) R)
           t_1))))
    double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
    	double t_0 = sin(phi2) * sin(phi1);
    	double t_1 = acos(fma((cos(lambda2) * cos(phi2)), cos(phi1), t_0)) * R;
    	double tmp;
    	if (lambda2 <= -0.000118) {
    		tmp = t_1;
    	} else if (lambda2 <= 3.3e-6) {
    		tmp = acos(fma(cos(lambda1), (cos(phi2) * cos(phi1)), t_0)) * R;
    	} else {
    		tmp = t_1;
    	}
    	return tmp;
    }
    
    function code(R, lambda1, lambda2, phi1, phi2)
    	t_0 = Float64(sin(phi2) * sin(phi1))
    	t_1 = Float64(acos(fma(Float64(cos(lambda2) * cos(phi2)), cos(phi1), t_0)) * R)
    	tmp = 0.0
    	if (lambda2 <= -0.000118)
    		tmp = t_1;
    	elseif (lambda2 <= 3.3e-6)
    		tmp = Float64(acos(fma(cos(lambda1), Float64(cos(phi2) * cos(phi1)), t_0)) * R);
    	else
    		tmp = t_1;
    	end
    	return tmp
    end
    
    code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[ArcCos[N[(N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision] + t$95$0), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[lambda2, -0.000118], t$95$1, If[LessEqual[lambda2, 3.3e-6], N[(N[ArcCos[N[(N[Cos[lambda1], $MachinePrecision] * N[(N[Cos[phi2], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision] + t$95$0), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], t$95$1]]]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_0 := \sin \phi_2 \cdot \sin \phi_1\\
    t_1 := \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, t\_0\right)\right) \cdot R\\
    \mathbf{if}\;\lambda_2 \leq -0.000118:\\
    \;\;\;\;t\_1\\
    
    \mathbf{elif}\;\lambda_2 \leq 3.3 \cdot 10^{-6}:\\
    \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, t\_0\right)\right) \cdot R\\
    
    \mathbf{else}:\\
    \;\;\;\;t\_1\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if lambda2 < -1.18e-4 or 3.30000000000000017e-6 < lambda2

      1. Initial program 60.7%

        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      2. Taylor expanded in lambda1 around 0

        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right)\right) + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
      3. Step-by-step derivation
        1. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right)\right) \cdot \cos \phi_1 + \color{blue}{\sin \phi_1} \cdot \sin \phi_2\right) \cdot R \]
        2. lower-fma.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right), \color{blue}{\cos \phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        3. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot \cos \phi_2, \cos \color{blue}{\phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        4. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot \cos \phi_2, \cos \color{blue}{\phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        5. cos-negN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        6. lower-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        7. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        8. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        9. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        10. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        11. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        12. lift-sin.f6460.4

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
      4. Applied rewrites60.4%

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]

      if -1.18e-4 < lambda2 < 3.30000000000000017e-6

      1. Initial program 88.3%

        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      2. Taylor expanded in lambda2 around 0

        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \lambda_1 \cdot \left(\cos \phi_1 \cdot \cos \phi_2\right) + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
      3. Step-by-step derivation
        1. lower-fma.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \phi_1 \cdot \cos \phi_2}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        2. lower-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \phi_1} \cdot \cos \phi_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        3. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \color{blue}{\cos \phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        4. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \color{blue}{\cos \phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        5. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \color{blue}{\phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        6. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
        7. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        8. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        9. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        10. lift-sin.f6488.2

          \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
      4. Applied rewrites88.2%

        \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]
    3. Recombined 2 regimes into one program.
    4. Add Preprocessing

    Alternative 14: 68.6% accurate, 1.0× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R\\ \mathbf{if}\;\lambda_2 \leq -3.5 \cdot 10^{-7}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\lambda_2 \leq 0.034:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
    (FPCore (R lambda1 lambda2 phi1 phi2)
     :precision binary64
     (let* ((t_0
             (*
              (acos
               (+ 0.0 (* (* (cos phi1) (cos phi2)) (cos (- lambda1 lambda2)))))
              R)))
       (if (<= lambda2 -3.5e-7)
         t_0
         (if (<= lambda2 0.034)
           (*
            (acos
             (fma
              (cos lambda1)
              (* (cos phi2) (cos phi1))
              (* (sin phi2) (sin phi1))))
            R)
           t_0))))
    double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
    	double t_0 = acos((0.0 + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * R;
    	double tmp;
    	if (lambda2 <= -3.5e-7) {
    		tmp = t_0;
    	} else if (lambda2 <= 0.034) {
    		tmp = acos(fma(cos(lambda1), (cos(phi2) * cos(phi1)), (sin(phi2) * sin(phi1)))) * R;
    	} else {
    		tmp = t_0;
    	}
    	return tmp;
    }
    
    function code(R, lambda1, lambda2, phi1, phi2)
    	t_0 = Float64(acos(Float64(0.0 + Float64(Float64(cos(phi1) * cos(phi2)) * cos(Float64(lambda1 - lambda2))))) * R)
    	tmp = 0.0
    	if (lambda2 <= -3.5e-7)
    		tmp = t_0;
    	elseif (lambda2 <= 0.034)
    		tmp = Float64(acos(fma(cos(lambda1), Float64(cos(phi2) * cos(phi1)), Float64(sin(phi2) * sin(phi1)))) * R);
    	else
    		tmp = t_0;
    	end
    	return tmp
    end
    
    code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[ArcCos[N[(0.0 + N[(N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[lambda2, -3.5e-7], t$95$0, If[LessEqual[lambda2, 0.034], N[(N[ArcCos[N[(N[Cos[lambda1], $MachinePrecision] * N[(N[Cos[phi2], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], t$95$0]]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_0 := \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R\\
    \mathbf{if}\;\lambda_2 \leq -3.5 \cdot 10^{-7}:\\
    \;\;\;\;t\_0\\
    
    \mathbf{elif}\;\lambda_2 \leq 0.034:\\
    \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\
    
    \mathbf{else}:\\
    \;\;\;\;t\_0\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if lambda2 < -3.49999999999999984e-7 or 0.034000000000000002 < lambda2

      1. Initial program 60.6%

        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      2. Step-by-step derivation
        1. lift-*.f64N/A

          \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        2. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        3. lift-sin.f64N/A

          \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        4. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        5. sin-multN/A

          \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        6. lower-/.f64N/A

          \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        7. lower--.f64N/A

          \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        8. lower-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        9. lower--.f64N/A

          \[\leadsto \cos^{-1} \left(\frac{\cos \color{blue}{\left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        10. lower-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \color{blue}{\cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        11. lower-+.f6450.1

          \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \color{blue}{\left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      3. Applied rewrites50.1%

        \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      4. Taylor expanded in phi2 around 0

        \[\leadsto \cos^{-1} \left(\color{blue}{\frac{1}{2} \cdot \left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right)} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      5. Step-by-step derivation
        1. *-commutativeN/A

          \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        2. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        3. cos-neg-revN/A

          \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        4. lower--.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        5. lift-cos.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        6. lift-cos.f6450.0

          \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      6. Applied rewrites50.0%

        \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      7. Taylor expanded in phi1 around 0

        \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
      8. Step-by-step derivation
        1. Applied rewrites50.0%

          \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]

        if -3.49999999999999984e-7 < lambda2 < 0.034000000000000002

        1. Initial program 88.2%

          \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        2. Taylor expanded in lambda2 around 0

          \[\leadsto \cos^{-1} \color{blue}{\left(\cos \lambda_1 \cdot \left(\cos \phi_1 \cdot \cos \phi_2\right) + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
        3. Step-by-step derivation
          1. lower-fma.f64N/A

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \phi_1 \cdot \cos \phi_2}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
          2. lower-cos.f64N/A

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \color{blue}{\cos \phi_1} \cdot \cos \phi_2, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
          3. *-commutativeN/A

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \color{blue}{\cos \phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
          4. lower-*.f64N/A

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \color{blue}{\cos \phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
          5. lift-cos.f64N/A

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \color{blue}{\phi_1}, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
          6. lift-cos.f64N/A

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_1 \cdot \sin \phi_2\right)\right) \cdot R \]
          7. *-commutativeN/A

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
          8. lower-*.f64N/A

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
          9. lift-sin.f64N/A

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
          10. lift-sin.f6488.0

            \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
        4. Applied rewrites88.0%

          \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]
      9. Recombined 2 regimes into one program.
      10. Add Preprocessing

      Alternative 15: 63.6% accurate, 0.9× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \phi_1 \cdot \cos \phi_2\\ t_1 := \cos \left(\lambda_1 - \lambda_2\right)\\ \mathbf{if}\;t\_1 \leq 0.9986:\\ \;\;\;\;\cos^{-1} \left(0 + t\_0 \cdot t\_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + t\_0 \cdot \mathsf{fma}\left(\mathsf{fma}\left(\lambda_2 \cdot \lambda_2, -0.001388888888888889, 0.041666666666666664\right) \cdot \left(\lambda_2 \cdot \lambda_2\right) - 0.5, \lambda_2 \cdot \lambda_2, 1\right)\right) \cdot R\\ \end{array} \end{array} \]
      (FPCore (R lambda1 lambda2 phi1 phi2)
       :precision binary64
       (let* ((t_0 (* (cos phi1) (cos phi2))) (t_1 (cos (- lambda1 lambda2))))
         (if (<= t_1 0.9986)
           (* (acos (+ 0.0 (* t_0 t_1))) R)
           (*
            (acos
             (+
              (* (sin phi1) (sin phi2))
              (*
               t_0
               (fma
                (-
                 (*
                  (fma
                   (* lambda2 lambda2)
                   -0.001388888888888889
                   0.041666666666666664)
                  (* lambda2 lambda2))
                 0.5)
                (* lambda2 lambda2)
                1.0))))
            R))))
      double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
      	double t_0 = cos(phi1) * cos(phi2);
      	double t_1 = cos((lambda1 - lambda2));
      	double tmp;
      	if (t_1 <= 0.9986) {
      		tmp = acos((0.0 + (t_0 * t_1))) * R;
      	} else {
      		tmp = acos(((sin(phi1) * sin(phi2)) + (t_0 * fma(((fma((lambda2 * lambda2), -0.001388888888888889, 0.041666666666666664) * (lambda2 * lambda2)) - 0.5), (lambda2 * lambda2), 1.0)))) * R;
      	}
      	return tmp;
      }
      
      function code(R, lambda1, lambda2, phi1, phi2)
      	t_0 = Float64(cos(phi1) * cos(phi2))
      	t_1 = cos(Float64(lambda1 - lambda2))
      	tmp = 0.0
      	if (t_1 <= 0.9986)
      		tmp = Float64(acos(Float64(0.0 + Float64(t_0 * t_1))) * R);
      	else
      		tmp = Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(t_0 * fma(Float64(Float64(fma(Float64(lambda2 * lambda2), -0.001388888888888889, 0.041666666666666664) * Float64(lambda2 * lambda2)) - 0.5), Float64(lambda2 * lambda2), 1.0)))) * R);
      	end
      	return tmp
      end
      
      code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[t$95$1, 0.9986], N[(N[ArcCos[N[(0.0 + N[(t$95$0 * t$95$1), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(t$95$0 * N[(N[(N[(N[(N[(lambda2 * lambda2), $MachinePrecision] * -0.001388888888888889 + 0.041666666666666664), $MachinePrecision] * N[(lambda2 * lambda2), $MachinePrecision]), $MachinePrecision] - 0.5), $MachinePrecision] * N[(lambda2 * lambda2), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      t_0 := \cos \phi_1 \cdot \cos \phi_2\\
      t_1 := \cos \left(\lambda_1 - \lambda_2\right)\\
      \mathbf{if}\;t\_1 \leq 0.9986:\\
      \;\;\;\;\cos^{-1} \left(0 + t\_0 \cdot t\_1\right) \cdot R\\
      
      \mathbf{else}:\\
      \;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + t\_0 \cdot \mathsf{fma}\left(\mathsf{fma}\left(\lambda_2 \cdot \lambda_2, -0.001388888888888889, 0.041666666666666664\right) \cdot \left(\lambda_2 \cdot \lambda_2\right) - 0.5, \lambda_2 \cdot \lambda_2, 1\right)\right) \cdot R\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (cos.f64 (-.f64 lambda1 lambda2)) < 0.998600000000000043

        1. Initial program 73.0%

          \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        2. Step-by-step derivation
          1. lift-*.f64N/A

            \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          2. lift-sin.f64N/A

            \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          3. lift-sin.f64N/A

            \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          4. *-commutativeN/A

            \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          5. sin-multN/A

            \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          6. lower-/.f64N/A

            \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          7. lower--.f64N/A

            \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          8. lower-cos.f64N/A

            \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          9. lower--.f64N/A

            \[\leadsto \cos^{-1} \left(\frac{\cos \color{blue}{\left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          10. lower-cos.f64N/A

            \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \color{blue}{\cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          11. lower-+.f6459.3

            \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \color{blue}{\left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        3. Applied rewrites59.3%

          \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        4. Taylor expanded in phi2 around 0

          \[\leadsto \cos^{-1} \left(\color{blue}{\frac{1}{2} \cdot \left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right)} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        5. Step-by-step derivation
          1. *-commutativeN/A

            \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          2. lower-*.f64N/A

            \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          3. cos-neg-revN/A

            \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          4. lower--.f64N/A

            \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          5. lift-cos.f64N/A

            \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          6. lift-cos.f6459.3

            \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        6. Applied rewrites59.3%

          \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        7. Taylor expanded in phi1 around 0

          \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
        8. Step-by-step derivation
          1. Applied rewrites59.3%

            \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]

          if 0.998600000000000043 < (cos.f64 (-.f64 lambda1 lambda2))

          1. Initial program 77.6%

            \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          2. Taylor expanded in lambda1 around 0

            \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)}\right) \cdot R \]
          3. Step-by-step derivation
            1. cos-negN/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
            2. lower-cos.f6475.8

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
          4. Applied rewrites75.8%

            \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \lambda_2}\right) \cdot R \]
          5. Taylor expanded in lambda2 around 0

            \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(1 + \color{blue}{{\lambda_2}^{2} \cdot \left({\lambda_2}^{2} \cdot \left(\frac{1}{24} + \frac{-1}{720} \cdot {\lambda_2}^{2}\right) - \frac{1}{2}\right)}\right)\right) \cdot R \]
          6. Step-by-step derivation
            1. +-commutativeN/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left({\lambda_2}^{2} \cdot \left({\lambda_2}^{2} \cdot \left(\frac{1}{24} + \frac{-1}{720} \cdot {\lambda_2}^{2}\right) - \frac{1}{2}\right) + 1\right)\right) \cdot R \]
            2. *-commutativeN/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\left({\lambda_2}^{2} \cdot \left(\frac{1}{24} + \frac{-1}{720} \cdot {\lambda_2}^{2}\right) - \frac{1}{2}\right) \cdot {\lambda_2}^{2} + 1\right)\right) \cdot R \]
            3. lower-fma.f64N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left({\lambda_2}^{2} \cdot \left(\frac{1}{24} + \frac{-1}{720} \cdot {\lambda_2}^{2}\right) - \frac{1}{2}, {\lambda_2}^{\color{blue}{2}}, 1\right)\right) \cdot R \]
            4. lower--.f64N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left({\lambda_2}^{2} \cdot \left(\frac{1}{24} + \frac{-1}{720} \cdot {\lambda_2}^{2}\right) - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            5. *-commutativeN/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\left(\frac{1}{24} + \frac{-1}{720} \cdot {\lambda_2}^{2}\right) \cdot {\lambda_2}^{2} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            6. lower-*.f64N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\left(\frac{1}{24} + \frac{-1}{720} \cdot {\lambda_2}^{2}\right) \cdot {\lambda_2}^{2} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            7. +-commutativeN/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\left(\frac{-1}{720} \cdot {\lambda_2}^{2} + \frac{1}{24}\right) \cdot {\lambda_2}^{2} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            8. *-commutativeN/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\left({\lambda_2}^{2} \cdot \frac{-1}{720} + \frac{1}{24}\right) \cdot {\lambda_2}^{2} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            9. lower-fma.f64N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left({\lambda_2}^{2}, \frac{-1}{720}, \frac{1}{24}\right) \cdot {\lambda_2}^{2} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            10. unpow2N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\lambda_2 \cdot \lambda_2, \frac{-1}{720}, \frac{1}{24}\right) \cdot {\lambda_2}^{2} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            11. lower-*.f64N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\lambda_2 \cdot \lambda_2, \frac{-1}{720}, \frac{1}{24}\right) \cdot {\lambda_2}^{2} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            12. unpow2N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\lambda_2 \cdot \lambda_2, \frac{-1}{720}, \frac{1}{24}\right) \cdot \left(\lambda_2 \cdot \lambda_2\right) - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            13. lower-*.f64N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\lambda_2 \cdot \lambda_2, \frac{-1}{720}, \frac{1}{24}\right) \cdot \left(\lambda_2 \cdot \lambda_2\right) - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
            14. unpow2N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\lambda_2 \cdot \lambda_2, \frac{-1}{720}, \frac{1}{24}\right) \cdot \left(\lambda_2 \cdot \lambda_2\right) - \frac{1}{2}, \lambda_2 \cdot \lambda_2, 1\right)\right) \cdot R \]
            15. lower-*.f6473.9

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\lambda_2 \cdot \lambda_2, -0.001388888888888889, 0.041666666666666664\right) \cdot \left(\lambda_2 \cdot \lambda_2\right) - 0.5, \lambda_2 \cdot \lambda_2, 1\right)\right) \cdot R \]
          7. Applied rewrites73.9%

            \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\mathsf{fma}\left(\lambda_2 \cdot \lambda_2, -0.001388888888888889, 0.041666666666666664\right) \cdot \left(\lambda_2 \cdot \lambda_2\right) - 0.5, \color{blue}{\lambda_2 \cdot \lambda_2}, 1\right)\right) \cdot R \]
        9. Recombined 2 regimes into one program.
        10. Add Preprocessing

        Alternative 16: 63.6% accurate, 0.9× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \phi_1 \cdot \cos \phi_2\\ t_1 := \cos \left(\lambda_1 - \lambda_2\right)\\ \mathbf{if}\;t\_1 \leq 0.9986:\\ \;\;\;\;\cos^{-1} \left(0 + t\_0 \cdot t\_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + t\_0 \cdot \mathsf{fma}\left(\left(\lambda_2 \cdot \lambda_2\right) \cdot 0.041666666666666664 - 0.5, \lambda_2 \cdot \lambda_2, 1\right)\right) \cdot R\\ \end{array} \end{array} \]
        (FPCore (R lambda1 lambda2 phi1 phi2)
         :precision binary64
         (let* ((t_0 (* (cos phi1) (cos phi2))) (t_1 (cos (- lambda1 lambda2))))
           (if (<= t_1 0.9986)
             (* (acos (+ 0.0 (* t_0 t_1))) R)
             (*
              (acos
               (+
                (* (sin phi1) (sin phi2))
                (*
                 t_0
                 (fma
                  (- (* (* lambda2 lambda2) 0.041666666666666664) 0.5)
                  (* lambda2 lambda2)
                  1.0))))
              R))))
        double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
        	double t_0 = cos(phi1) * cos(phi2);
        	double t_1 = cos((lambda1 - lambda2));
        	double tmp;
        	if (t_1 <= 0.9986) {
        		tmp = acos((0.0 + (t_0 * t_1))) * R;
        	} else {
        		tmp = acos(((sin(phi1) * sin(phi2)) + (t_0 * fma((((lambda2 * lambda2) * 0.041666666666666664) - 0.5), (lambda2 * lambda2), 1.0)))) * R;
        	}
        	return tmp;
        }
        
        function code(R, lambda1, lambda2, phi1, phi2)
        	t_0 = Float64(cos(phi1) * cos(phi2))
        	t_1 = cos(Float64(lambda1 - lambda2))
        	tmp = 0.0
        	if (t_1 <= 0.9986)
        		tmp = Float64(acos(Float64(0.0 + Float64(t_0 * t_1))) * R);
        	else
        		tmp = Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(t_0 * fma(Float64(Float64(Float64(lambda2 * lambda2) * 0.041666666666666664) - 0.5), Float64(lambda2 * lambda2), 1.0)))) * R);
        	end
        	return tmp
        end
        
        code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[t$95$1, 0.9986], N[(N[ArcCos[N[(0.0 + N[(t$95$0 * t$95$1), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(t$95$0 * N[(N[(N[(N[(lambda2 * lambda2), $MachinePrecision] * 0.041666666666666664), $MachinePrecision] - 0.5), $MachinePrecision] * N[(lambda2 * lambda2), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_0 := \cos \phi_1 \cdot \cos \phi_2\\
        t_1 := \cos \left(\lambda_1 - \lambda_2\right)\\
        \mathbf{if}\;t\_1 \leq 0.9986:\\
        \;\;\;\;\cos^{-1} \left(0 + t\_0 \cdot t\_1\right) \cdot R\\
        
        \mathbf{else}:\\
        \;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + t\_0 \cdot \mathsf{fma}\left(\left(\lambda_2 \cdot \lambda_2\right) \cdot 0.041666666666666664 - 0.5, \lambda_2 \cdot \lambda_2, 1\right)\right) \cdot R\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if (cos.f64 (-.f64 lambda1 lambda2)) < 0.998600000000000043

          1. Initial program 73.0%

            \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          2. Step-by-step derivation
            1. lift-*.f64N/A

              \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            2. lift-sin.f64N/A

              \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            3. lift-sin.f64N/A

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            4. *-commutativeN/A

              \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            5. sin-multN/A

              \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            6. lower-/.f64N/A

              \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            7. lower--.f64N/A

              \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            8. lower-cos.f64N/A

              \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            9. lower--.f64N/A

              \[\leadsto \cos^{-1} \left(\frac{\cos \color{blue}{\left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            10. lower-cos.f64N/A

              \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \color{blue}{\cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            11. lower-+.f6459.3

              \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \color{blue}{\left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          3. Applied rewrites59.3%

            \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          4. Taylor expanded in phi2 around 0

            \[\leadsto \cos^{-1} \left(\color{blue}{\frac{1}{2} \cdot \left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right)} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          5. Step-by-step derivation
            1. *-commutativeN/A

              \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            2. lower-*.f64N/A

              \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            3. cos-neg-revN/A

              \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            4. lower--.f64N/A

              \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            5. lift-cos.f64N/A

              \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            6. lift-cos.f6459.3

              \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          6. Applied rewrites59.3%

            \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          7. Taylor expanded in phi1 around 0

            \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
          8. Step-by-step derivation
            1. Applied rewrites59.3%

              \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]

            if 0.998600000000000043 < (cos.f64 (-.f64 lambda1 lambda2))

            1. Initial program 77.6%

              \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            2. Taylor expanded in lambda1 around 0

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)}\right) \cdot R \]
            3. Step-by-step derivation
              1. cos-negN/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
              2. lower-cos.f6475.8

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
            4. Applied rewrites75.8%

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \lambda_2}\right) \cdot R \]
            5. Taylor expanded in lambda2 around 0

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(1 + \color{blue}{{\lambda_2}^{2} \cdot \left(\frac{1}{24} \cdot {\lambda_2}^{2} - \frac{1}{2}\right)}\right)\right) \cdot R \]
            6. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left({\lambda_2}^{2} \cdot \left(\frac{1}{24} \cdot {\lambda_2}^{2} - \frac{1}{2}\right) + 1\right)\right) \cdot R \]
              2. *-commutativeN/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\left(\frac{1}{24} \cdot {\lambda_2}^{2} - \frac{1}{2}\right) \cdot {\lambda_2}^{2} + 1\right)\right) \cdot R \]
              3. lower-fma.f64N/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\frac{1}{24} \cdot {\lambda_2}^{2} - \frac{1}{2}, {\lambda_2}^{\color{blue}{2}}, 1\right)\right) \cdot R \]
              4. lower--.f64N/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\frac{1}{24} \cdot {\lambda_2}^{2} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
              5. *-commutativeN/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left({\lambda_2}^{2} \cdot \frac{1}{24} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
              6. lower-*.f64N/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left({\lambda_2}^{2} \cdot \frac{1}{24} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
              7. unpow2N/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\left(\lambda_2 \cdot \lambda_2\right) \cdot \frac{1}{24} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
              8. lower-*.f64N/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\left(\lambda_2 \cdot \lambda_2\right) \cdot \frac{1}{24} - \frac{1}{2}, {\lambda_2}^{2}, 1\right)\right) \cdot R \]
              9. unpow2N/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\left(\lambda_2 \cdot \lambda_2\right) \cdot \frac{1}{24} - \frac{1}{2}, \lambda_2 \cdot \lambda_2, 1\right)\right) \cdot R \]
              10. lower-*.f6473.9

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\left(\lambda_2 \cdot \lambda_2\right) \cdot 0.041666666666666664 - 0.5, \lambda_2 \cdot \lambda_2, 1\right)\right) \cdot R \]
            7. Applied rewrites73.9%

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\left(\lambda_2 \cdot \lambda_2\right) \cdot 0.041666666666666664 - 0.5, \color{blue}{\lambda_2 \cdot \lambda_2}, 1\right)\right) \cdot R \]
          9. Recombined 2 regimes into one program.
          10. Add Preprocessing

          Alternative 17: 63.0% accurate, 0.9× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \phi_1 \cdot \cos \phi_2\\ t_1 := \cos \left(\lambda_1 - \lambda_2\right)\\ \mathbf{if}\;t\_1 \leq 0.99999995:\\ \;\;\;\;\cos^{-1} \left(0 + t\_0 \cdot t\_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + t\_0 \cdot \mathsf{fma}\left(\lambda_2 \cdot \lambda_2, -0.5, 1\right)\right) \cdot R\\ \end{array} \end{array} \]
          (FPCore (R lambda1 lambda2 phi1 phi2)
           :precision binary64
           (let* ((t_0 (* (cos phi1) (cos phi2))) (t_1 (cos (- lambda1 lambda2))))
             (if (<= t_1 0.99999995)
               (* (acos (+ 0.0 (* t_0 t_1))) R)
               (*
                (acos
                 (+
                  (* (sin phi1) (sin phi2))
                  (* t_0 (fma (* lambda2 lambda2) -0.5 1.0))))
                R))))
          double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
          	double t_0 = cos(phi1) * cos(phi2);
          	double t_1 = cos((lambda1 - lambda2));
          	double tmp;
          	if (t_1 <= 0.99999995) {
          		tmp = acos((0.0 + (t_0 * t_1))) * R;
          	} else {
          		tmp = acos(((sin(phi1) * sin(phi2)) + (t_0 * fma((lambda2 * lambda2), -0.5, 1.0)))) * R;
          	}
          	return tmp;
          }
          
          function code(R, lambda1, lambda2, phi1, phi2)
          	t_0 = Float64(cos(phi1) * cos(phi2))
          	t_1 = cos(Float64(lambda1 - lambda2))
          	tmp = 0.0
          	if (t_1 <= 0.99999995)
          		tmp = Float64(acos(Float64(0.0 + Float64(t_0 * t_1))) * R);
          	else
          		tmp = Float64(acos(Float64(Float64(sin(phi1) * sin(phi2)) + Float64(t_0 * fma(Float64(lambda2 * lambda2), -0.5, 1.0)))) * R);
          	end
          	return tmp
          end
          
          code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[t$95$1, 0.99999995], N[(N[ArcCos[N[(0.0 + N[(t$95$0 * t$95$1), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision]), $MachinePrecision] + N[(t$95$0 * N[(N[(lambda2 * lambda2), $MachinePrecision] * -0.5 + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_0 := \cos \phi_1 \cdot \cos \phi_2\\
          t_1 := \cos \left(\lambda_1 - \lambda_2\right)\\
          \mathbf{if}\;t\_1 \leq 0.99999995:\\
          \;\;\;\;\cos^{-1} \left(0 + t\_0 \cdot t\_1\right) \cdot R\\
          
          \mathbf{else}:\\
          \;\;\;\;\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + t\_0 \cdot \mathsf{fma}\left(\lambda_2 \cdot \lambda_2, -0.5, 1\right)\right) \cdot R\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if (cos.f64 (-.f64 lambda1 lambda2)) < 0.999999949999999971

            1. Initial program 73.1%

              \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            2. Step-by-step derivation
              1. lift-*.f64N/A

                \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              2. lift-sin.f64N/A

                \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              3. lift-sin.f64N/A

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              4. *-commutativeN/A

                \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              5. sin-multN/A

                \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              6. lower-/.f64N/A

                \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              7. lower--.f64N/A

                \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              8. lower-cos.f64N/A

                \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              9. lower--.f64N/A

                \[\leadsto \cos^{-1} \left(\frac{\cos \color{blue}{\left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              10. lower-cos.f64N/A

                \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \color{blue}{\cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              11. lower-+.f6459.4

                \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \color{blue}{\left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            3. Applied rewrites59.4%

              \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            4. Taylor expanded in phi2 around 0

              \[\leadsto \cos^{-1} \left(\color{blue}{\frac{1}{2} \cdot \left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right)} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            5. Step-by-step derivation
              1. *-commutativeN/A

                \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              2. lower-*.f64N/A

                \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              3. cos-neg-revN/A

                \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              4. lower--.f64N/A

                \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              5. lift-cos.f64N/A

                \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              6. lift-cos.f6459.4

                \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            6. Applied rewrites59.4%

              \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            7. Taylor expanded in phi1 around 0

              \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            8. Step-by-step derivation
              1. Applied rewrites59.4%

                \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]

              if 0.999999949999999971 < (cos.f64 (-.f64 lambda1 lambda2))

              1. Initial program 77.7%

                \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              2. Taylor expanded in lambda1 around 0

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)}\right) \cdot R \]
              3. Step-by-step derivation
                1. cos-negN/A

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
                2. lower-cos.f6477.4

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
              4. Applied rewrites77.4%

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \lambda_2}\right) \cdot R \]
              5. Taylor expanded in lambda2 around 0

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(1 + \color{blue}{\frac{-1}{2} \cdot {\lambda_2}^{2}}\right)\right) \cdot R \]
              6. Step-by-step derivation
                1. +-commutativeN/A

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left(\frac{-1}{2} \cdot {\lambda_2}^{2} + 1\right)\right) \cdot R \]
                2. *-commutativeN/A

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \left({\lambda_2}^{2} \cdot \frac{-1}{2} + 1\right)\right) \cdot R \]
                3. lower-fma.f64N/A

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left({\lambda_2}^{2}, \frac{-1}{2}, 1\right)\right) \cdot R \]
                4. unpow2N/A

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\lambda_2 \cdot \lambda_2, \frac{-1}{2}, 1\right)\right) \cdot R \]
                5. lower-*.f6477.3

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\lambda_2 \cdot \lambda_2, -0.5, 1\right)\right) \cdot R \]
              7. Applied rewrites77.3%

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\lambda_2 \cdot \lambda_2, \color{blue}{-0.5}, 1\right)\right) \cdot R \]
            9. Recombined 2 regimes into one program.
            10. Add Preprocessing

            Alternative 18: 63.0% accurate, 1.0× speedup?

            \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \phi_1 \cdot \cos \phi_2\\ t_1 := \cos \left(\lambda_1 - \lambda_2\right)\\ \mathbf{if}\;t\_1 \leq 0.99999995:\\ \;\;\;\;\cos^{-1} \left(0 + t\_0 \cdot t\_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_1, \sin \phi_2, t\_0 \cdot 1\right)\right) \cdot R\\ \end{array} \end{array} \]
            (FPCore (R lambda1 lambda2 phi1 phi2)
             :precision binary64
             (let* ((t_0 (* (cos phi1) (cos phi2))) (t_1 (cos (- lambda1 lambda2))))
               (if (<= t_1 0.99999995)
                 (* (acos (+ 0.0 (* t_0 t_1))) R)
                 (* (acos (fma (sin phi1) (sin phi2) (* t_0 1.0))) R))))
            double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
            	double t_0 = cos(phi1) * cos(phi2);
            	double t_1 = cos((lambda1 - lambda2));
            	double tmp;
            	if (t_1 <= 0.99999995) {
            		tmp = acos((0.0 + (t_0 * t_1))) * R;
            	} else {
            		tmp = acos(fma(sin(phi1), sin(phi2), (t_0 * 1.0))) * R;
            	}
            	return tmp;
            }
            
            function code(R, lambda1, lambda2, phi1, phi2)
            	t_0 = Float64(cos(phi1) * cos(phi2))
            	t_1 = cos(Float64(lambda1 - lambda2))
            	tmp = 0.0
            	if (t_1 <= 0.99999995)
            		tmp = Float64(acos(Float64(0.0 + Float64(t_0 * t_1))) * R);
            	else
            		tmp = Float64(acos(fma(sin(phi1), sin(phi2), Float64(t_0 * 1.0))) * R);
            	end
            	return tmp
            end
            
            code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[t$95$1, 0.99999995], N[(N[ArcCos[N[(0.0 + N[(t$95$0 * t$95$1), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(N[Sin[phi1], $MachinePrecision] * N[Sin[phi2], $MachinePrecision] + N[(t$95$0 * 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]]
            
            \begin{array}{l}
            
            \\
            \begin{array}{l}
            t_0 := \cos \phi_1 \cdot \cos \phi_2\\
            t_1 := \cos \left(\lambda_1 - \lambda_2\right)\\
            \mathbf{if}\;t\_1 \leq 0.99999995:\\
            \;\;\;\;\cos^{-1} \left(0 + t\_0 \cdot t\_1\right) \cdot R\\
            
            \mathbf{else}:\\
            \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_1, \sin \phi_2, t\_0 \cdot 1\right)\right) \cdot R\\
            
            
            \end{array}
            \end{array}
            
            Derivation
            1. Split input into 2 regimes
            2. if (cos.f64 (-.f64 lambda1 lambda2)) < 0.999999949999999971

              1. Initial program 73.1%

                \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              2. Step-by-step derivation
                1. lift-*.f64N/A

                  \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                2. lift-sin.f64N/A

                  \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                3. lift-sin.f64N/A

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                4. *-commutativeN/A

                  \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                5. sin-multN/A

                  \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                6. lower-/.f64N/A

                  \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                7. lower--.f64N/A

                  \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                8. lower-cos.f64N/A

                  \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                9. lower--.f64N/A

                  \[\leadsto \cos^{-1} \left(\frac{\cos \color{blue}{\left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                10. lower-cos.f64N/A

                  \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \color{blue}{\cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                11. lower-+.f6459.4

                  \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \color{blue}{\left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              3. Applied rewrites59.4%

                \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              4. Taylor expanded in phi2 around 0

                \[\leadsto \cos^{-1} \left(\color{blue}{\frac{1}{2} \cdot \left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right)} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              5. Step-by-step derivation
                1. *-commutativeN/A

                  \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                2. lower-*.f64N/A

                  \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                3. cos-neg-revN/A

                  \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                4. lower--.f64N/A

                  \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                5. lift-cos.f64N/A

                  \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                6. lift-cos.f6459.4

                  \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              6. Applied rewrites59.4%

                \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              7. Taylor expanded in phi1 around 0

                \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              8. Step-by-step derivation
                1. Applied rewrites59.4%

                  \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]

                if 0.999999949999999971 < (cos.f64 (-.f64 lambda1 lambda2))

                1. Initial program 77.7%

                  \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                2. Taylor expanded in lambda1 around 0

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)}\right) \cdot R \]
                3. Step-by-step derivation
                  1. cos-negN/A

                    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
                  2. lower-cos.f6477.4

                    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \lambda_2\right) \cdot R \]
                4. Applied rewrites77.4%

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \color{blue}{\cos \lambda_2}\right) \cdot R \]
                5. Taylor expanded in lambda2 around 0

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right) \cdot R \]
                6. Step-by-step derivation
                  1. Applied rewrites77.1%

                    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right) \cdot R \]
                  2. Step-by-step derivation
                    1. lift-+.f64N/A

                      \[\leadsto \cos^{-1} \color{blue}{\left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right)} \cdot R \]
                    2. lift-*.f64N/A

                      \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right) \cdot R \]
                    3. lift-sin.f64N/A

                      \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right) \cdot R \]
                    4. lift-sin.f64N/A

                      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right) \cdot R \]
                    5. lower-fma.f64N/A

                      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_1, \sin \phi_2, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right)\right)} \cdot R \]
                    6. lift-sin.f64N/A

                      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\sin \phi_1}, \sin \phi_2, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right)\right) \cdot R \]
                    7. lift-sin.f6477.1

                      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_1, \color{blue}{\sin \phi_2}, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right)\right) \cdot R \]
                  3. Applied rewrites77.1%

                    \[\leadsto \color{blue}{\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_1, \sin \phi_2, \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot 1\right)\right)} \cdot R \]
                7. Recombined 2 regimes into one program.
                8. Add Preprocessing

                Alternative 19: 58.9% accurate, 1.6× speedup?

                \[\begin{array}{l} \\ \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \end{array} \]
                (FPCore (R lambda1 lambda2 phi1 phi2)
                 :precision binary64
                 (* (acos (+ 0.0 (* (* (cos phi1) (cos phi2)) (cos (- lambda1 lambda2))))) R))
                double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                	return acos((0.0 + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * R;
                }
                
                module fmin_fmax_functions
                    implicit none
                    private
                    public fmax
                    public fmin
                
                    interface fmax
                        module procedure fmax88
                        module procedure fmax44
                        module procedure fmax84
                        module procedure fmax48
                    end interface
                    interface fmin
                        module procedure fmin88
                        module procedure fmin44
                        module procedure fmin84
                        module procedure fmin48
                    end interface
                contains
                    real(8) function fmax88(x, y) result (res)
                        real(8), intent (in) :: x
                        real(8), intent (in) :: y
                        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                    end function
                    real(4) function fmax44(x, y) result (res)
                        real(4), intent (in) :: x
                        real(4), intent (in) :: y
                        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                    end function
                    real(8) function fmax84(x, y) result(res)
                        real(8), intent (in) :: x
                        real(4), intent (in) :: y
                        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
                    end function
                    real(8) function fmax48(x, y) result(res)
                        real(4), intent (in) :: x
                        real(8), intent (in) :: y
                        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
                    end function
                    real(8) function fmin88(x, y) result (res)
                        real(8), intent (in) :: x
                        real(8), intent (in) :: y
                        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                    end function
                    real(4) function fmin44(x, y) result (res)
                        real(4), intent (in) :: x
                        real(4), intent (in) :: y
                        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                    end function
                    real(8) function fmin84(x, y) result(res)
                        real(8), intent (in) :: x
                        real(4), intent (in) :: y
                        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
                    end function
                    real(8) function fmin48(x, y) result(res)
                        real(4), intent (in) :: x
                        real(8), intent (in) :: y
                        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
                    end function
                end module
                
                real(8) function code(r, lambda1, lambda2, phi1, phi2)
                use fmin_fmax_functions
                    real(8), intent (in) :: r
                    real(8), intent (in) :: lambda1
                    real(8), intent (in) :: lambda2
                    real(8), intent (in) :: phi1
                    real(8), intent (in) :: phi2
                    code = acos((0.0d0 + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * r
                end function
                
                public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                	return Math.acos((0.0 + ((Math.cos(phi1) * Math.cos(phi2)) * Math.cos((lambda1 - lambda2))))) * R;
                }
                
                def code(R, lambda1, lambda2, phi1, phi2):
                	return math.acos((0.0 + ((math.cos(phi1) * math.cos(phi2)) * math.cos((lambda1 - lambda2))))) * R
                
                function code(R, lambda1, lambda2, phi1, phi2)
                	return Float64(acos(Float64(0.0 + Float64(Float64(cos(phi1) * cos(phi2)) * cos(Float64(lambda1 - lambda2))))) * R)
                end
                
                function tmp = code(R, lambda1, lambda2, phi1, phi2)
                	tmp = acos((0.0 + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * R;
                end
                
                code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[(0.0 + N[(N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
                
                \begin{array}{l}
                
                \\
                \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R
                \end{array}
                
                Derivation
                1. Initial program 74.2%

                  \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                2. Step-by-step derivation
                  1. lift-*.f64N/A

                    \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1 \cdot \sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  2. lift-sin.f64N/A

                    \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  3. lift-sin.f64N/A

                    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \color{blue}{\sin \phi_2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  4. *-commutativeN/A

                    \[\leadsto \cos^{-1} \left(\color{blue}{\sin \phi_2 \cdot \sin \phi_1} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  5. sin-multN/A

                    \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  6. lower-/.f64N/A

                    \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  7. lower--.f64N/A

                    \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  8. lower-cos.f64N/A

                    \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\cos \left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  9. lower--.f64N/A

                    \[\leadsto \cos^{-1} \left(\frac{\cos \color{blue}{\left(\phi_2 - \phi_1\right)} - \cos \left(\phi_2 + \phi_1\right)}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  10. lower-cos.f64N/A

                    \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \color{blue}{\cos \left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  11. lower-+.f6458.8

                    \[\leadsto \cos^{-1} \left(\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \color{blue}{\left(\phi_2 + \phi_1\right)}}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                3. Applied rewrites58.8%

                  \[\leadsto \cos^{-1} \left(\color{blue}{\frac{\cos \left(\phi_2 - \phi_1\right) - \cos \left(\phi_2 + \phi_1\right)}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                4. Taylor expanded in phi2 around 0

                  \[\leadsto \cos^{-1} \left(\color{blue}{\frac{1}{2} \cdot \left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right)} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                5. Step-by-step derivation
                  1. *-commutativeN/A

                    \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  2. lower-*.f64N/A

                    \[\leadsto \cos^{-1} \left(\left(\cos \left(\mathsf{neg}\left(\phi_1\right)\right) - \cos \phi_1\right) \cdot \color{blue}{\frac{1}{2}} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  3. cos-neg-revN/A

                    \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  4. lower--.f64N/A

                    \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  5. lift-cos.f64N/A

                    \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot \frac{1}{2} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  6. lift-cos.f6458.9

                    \[\leadsto \cos^{-1} \left(\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                6. Applied rewrites58.9%

                  \[\leadsto \cos^{-1} \left(\color{blue}{\left(\cos \phi_1 - \cos \phi_1\right) \cdot 0.5} + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                7. Taylor expanded in phi1 around 0

                  \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                8. Step-by-step derivation
                  1. Applied rewrites58.9%

                    \[\leadsto \cos^{-1} \left(0 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  2. Add Preprocessing

                  Alternative 20: 50.7% accurate, 2.2× speedup?

                  \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\lambda_1 - \lambda_2\right)\\ \mathbf{if}\;\phi_1 \leq -32:\\ \;\;\;\;\cos^{-1} \left(t\_0 \cdot \cos \phi_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(t\_0 \cdot \cos \phi_2\right) \cdot R\\ \end{array} \end{array} \]
                  (FPCore (R lambda1 lambda2 phi1 phi2)
                   :precision binary64
                   (let* ((t_0 (cos (- lambda1 lambda2))))
                     (if (<= phi1 -32.0)
                       (* (acos (* t_0 (cos phi1))) R)
                       (* (acos (* t_0 (cos phi2))) R))))
                  double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                  	double t_0 = cos((lambda1 - lambda2));
                  	double tmp;
                  	if (phi1 <= -32.0) {
                  		tmp = acos((t_0 * cos(phi1))) * R;
                  	} else {
                  		tmp = acos((t_0 * cos(phi2))) * R;
                  	}
                  	return tmp;
                  }
                  
                  module fmin_fmax_functions
                      implicit none
                      private
                      public fmax
                      public fmin
                  
                      interface fmax
                          module procedure fmax88
                          module procedure fmax44
                          module procedure fmax84
                          module procedure fmax48
                      end interface
                      interface fmin
                          module procedure fmin88
                          module procedure fmin44
                          module procedure fmin84
                          module procedure fmin48
                      end interface
                  contains
                      real(8) function fmax88(x, y) result (res)
                          real(8), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                      end function
                      real(4) function fmax44(x, y) result (res)
                          real(4), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                      end function
                      real(8) function fmax84(x, y) result(res)
                          real(8), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
                      end function
                      real(8) function fmax48(x, y) result(res)
                          real(4), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
                      end function
                      real(8) function fmin88(x, y) result (res)
                          real(8), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                      end function
                      real(4) function fmin44(x, y) result (res)
                          real(4), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                      end function
                      real(8) function fmin84(x, y) result(res)
                          real(8), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
                      end function
                      real(8) function fmin48(x, y) result(res)
                          real(4), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
                      end function
                  end module
                  
                  real(8) function code(r, lambda1, lambda2, phi1, phi2)
                  use fmin_fmax_functions
                      real(8), intent (in) :: r
                      real(8), intent (in) :: lambda1
                      real(8), intent (in) :: lambda2
                      real(8), intent (in) :: phi1
                      real(8), intent (in) :: phi2
                      real(8) :: t_0
                      real(8) :: tmp
                      t_0 = cos((lambda1 - lambda2))
                      if (phi1 <= (-32.0d0)) then
                          tmp = acos((t_0 * cos(phi1))) * r
                      else
                          tmp = acos((t_0 * cos(phi2))) * r
                      end if
                      code = tmp
                  end function
                  
                  public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                  	double t_0 = Math.cos((lambda1 - lambda2));
                  	double tmp;
                  	if (phi1 <= -32.0) {
                  		tmp = Math.acos((t_0 * Math.cos(phi1))) * R;
                  	} else {
                  		tmp = Math.acos((t_0 * Math.cos(phi2))) * R;
                  	}
                  	return tmp;
                  }
                  
                  def code(R, lambda1, lambda2, phi1, phi2):
                  	t_0 = math.cos((lambda1 - lambda2))
                  	tmp = 0
                  	if phi1 <= -32.0:
                  		tmp = math.acos((t_0 * math.cos(phi1))) * R
                  	else:
                  		tmp = math.acos((t_0 * math.cos(phi2))) * R
                  	return tmp
                  
                  function code(R, lambda1, lambda2, phi1, phi2)
                  	t_0 = cos(Float64(lambda1 - lambda2))
                  	tmp = 0.0
                  	if (phi1 <= -32.0)
                  		tmp = Float64(acos(Float64(t_0 * cos(phi1))) * R);
                  	else
                  		tmp = Float64(acos(Float64(t_0 * cos(phi2))) * R);
                  	end
                  	return tmp
                  end
                  
                  function tmp_2 = code(R, lambda1, lambda2, phi1, phi2)
                  	t_0 = cos((lambda1 - lambda2));
                  	tmp = 0.0;
                  	if (phi1 <= -32.0)
                  		tmp = acos((t_0 * cos(phi1))) * R;
                  	else
                  		tmp = acos((t_0 * cos(phi2))) * R;
                  	end
                  	tmp_2 = tmp;
                  end
                  
                  code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[phi1, -32.0], N[(N[ArcCos[N[(t$95$0 * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(t$95$0 * N[Cos[phi2], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]
                  
                  \begin{array}{l}
                  
                  \\
                  \begin{array}{l}
                  t_0 := \cos \left(\lambda_1 - \lambda_2\right)\\
                  \mathbf{if}\;\phi_1 \leq -32:\\
                  \;\;\;\;\cos^{-1} \left(t\_0 \cdot \cos \phi_1\right) \cdot R\\
                  
                  \mathbf{else}:\\
                  \;\;\;\;\cos^{-1} \left(t\_0 \cdot \cos \phi_2\right) \cdot R\\
                  
                  
                  \end{array}
                  \end{array}
                  
                  Derivation
                  1. Split input into 2 regimes
                  2. if phi1 < -32

                    1. Initial program 78.7%

                      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                    2. Taylor expanded in phi2 around 0

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                    3. Step-by-step derivation
                      1. *-commutativeN/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                      2. lower-*.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                      3. lift-cos.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                      4. lift--.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      5. lift-cos.f6448.5

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                    4. Applied rewrites48.5%

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]

                    if -32 < phi1

                    1. Initial program 72.6%

                      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                    2. Taylor expanded in phi1 around 0

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                    3. Step-by-step derivation
                      1. *-commutativeN/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_2}\right) \cdot R \]
                      2. lower-*.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_2}\right) \cdot R \]
                      3. lift-cos.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_2}\right) \cdot R \]
                      4. lift--.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot R \]
                      5. lift-cos.f6451.5

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot R \]
                    4. Applied rewrites51.5%

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right)} \cdot R \]
                  3. Recombined 2 regimes into one program.
                  4. Add Preprocessing

                  Alternative 21: 43.2% accurate, 2.3× speedup?

                  \[\begin{array}{l} \\ \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \end{array} \]
                  (FPCore (R lambda1 lambda2 phi1 phi2)
                   :precision binary64
                   (* (acos (* (cos (- lambda1 lambda2)) (cos phi1))) R))
                  double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                  	return acos((cos((lambda1 - lambda2)) * cos(phi1))) * R;
                  }
                  
                  module fmin_fmax_functions
                      implicit none
                      private
                      public fmax
                      public fmin
                  
                      interface fmax
                          module procedure fmax88
                          module procedure fmax44
                          module procedure fmax84
                          module procedure fmax48
                      end interface
                      interface fmin
                          module procedure fmin88
                          module procedure fmin44
                          module procedure fmin84
                          module procedure fmin48
                      end interface
                  contains
                      real(8) function fmax88(x, y) result (res)
                          real(8), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                      end function
                      real(4) function fmax44(x, y) result (res)
                          real(4), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                      end function
                      real(8) function fmax84(x, y) result(res)
                          real(8), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
                      end function
                      real(8) function fmax48(x, y) result(res)
                          real(4), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
                      end function
                      real(8) function fmin88(x, y) result (res)
                          real(8), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                      end function
                      real(4) function fmin44(x, y) result (res)
                          real(4), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                      end function
                      real(8) function fmin84(x, y) result(res)
                          real(8), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
                      end function
                      real(8) function fmin48(x, y) result(res)
                          real(4), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
                      end function
                  end module
                  
                  real(8) function code(r, lambda1, lambda2, phi1, phi2)
                  use fmin_fmax_functions
                      real(8), intent (in) :: r
                      real(8), intent (in) :: lambda1
                      real(8), intent (in) :: lambda2
                      real(8), intent (in) :: phi1
                      real(8), intent (in) :: phi2
                      code = acos((cos((lambda1 - lambda2)) * cos(phi1))) * r
                  end function
                  
                  public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                  	return Math.acos((Math.cos((lambda1 - lambda2)) * Math.cos(phi1))) * R;
                  }
                  
                  def code(R, lambda1, lambda2, phi1, phi2):
                  	return math.acos((math.cos((lambda1 - lambda2)) * math.cos(phi1))) * R
                  
                  function code(R, lambda1, lambda2, phi1, phi2)
                  	return Float64(acos(Float64(cos(Float64(lambda1 - lambda2)) * cos(phi1))) * R)
                  end
                  
                  function tmp = code(R, lambda1, lambda2, phi1, phi2)
                  	tmp = acos((cos((lambda1 - lambda2)) * cos(phi1))) * R;
                  end
                  
                  code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
                  
                  \begin{array}{l}
                  
                  \\
                  \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R
                  \end{array}
                  
                  Derivation
                  1. Initial program 74.2%

                    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  2. Taylor expanded in phi2 around 0

                    \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                  3. Step-by-step derivation
                    1. *-commutativeN/A

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                    2. lower-*.f64N/A

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                    3. lift-cos.f64N/A

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                    4. lift--.f64N/A

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                    5. lift-cos.f6443.2

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                  4. Applied rewrites43.2%

                    \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                  5. Add Preprocessing

                  Alternative 22: 43.1% accurate, 2.2× speedup?

                  \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R\\ \mathbf{if}\;\lambda_2 \leq -3.4 \cdot 10^{-8}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\lambda_2 \leq 3.2 \cdot 10^{-6}:\\ \;\;\;\;\cos^{-1} \left(\cos \lambda_1 \cdot \cos \phi_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
                  (FPCore (R lambda1 lambda2 phi1 phi2)
                   :precision binary64
                   (let* ((t_0 (* (acos (* (cos lambda2) (cos phi1))) R)))
                     (if (<= lambda2 -3.4e-8)
                       t_0
                       (if (<= lambda2 3.2e-6) (* (acos (* (cos lambda1) (cos phi1))) R) t_0))))
                  double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                  	double t_0 = acos((cos(lambda2) * cos(phi1))) * R;
                  	double tmp;
                  	if (lambda2 <= -3.4e-8) {
                  		tmp = t_0;
                  	} else if (lambda2 <= 3.2e-6) {
                  		tmp = acos((cos(lambda1) * cos(phi1))) * R;
                  	} else {
                  		tmp = t_0;
                  	}
                  	return tmp;
                  }
                  
                  module fmin_fmax_functions
                      implicit none
                      private
                      public fmax
                      public fmin
                  
                      interface fmax
                          module procedure fmax88
                          module procedure fmax44
                          module procedure fmax84
                          module procedure fmax48
                      end interface
                      interface fmin
                          module procedure fmin88
                          module procedure fmin44
                          module procedure fmin84
                          module procedure fmin48
                      end interface
                  contains
                      real(8) function fmax88(x, y) result (res)
                          real(8), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                      end function
                      real(4) function fmax44(x, y) result (res)
                          real(4), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                      end function
                      real(8) function fmax84(x, y) result(res)
                          real(8), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
                      end function
                      real(8) function fmax48(x, y) result(res)
                          real(4), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
                      end function
                      real(8) function fmin88(x, y) result (res)
                          real(8), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                      end function
                      real(4) function fmin44(x, y) result (res)
                          real(4), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                      end function
                      real(8) function fmin84(x, y) result(res)
                          real(8), intent (in) :: x
                          real(4), intent (in) :: y
                          res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
                      end function
                      real(8) function fmin48(x, y) result(res)
                          real(4), intent (in) :: x
                          real(8), intent (in) :: y
                          res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
                      end function
                  end module
                  
                  real(8) function code(r, lambda1, lambda2, phi1, phi2)
                  use fmin_fmax_functions
                      real(8), intent (in) :: r
                      real(8), intent (in) :: lambda1
                      real(8), intent (in) :: lambda2
                      real(8), intent (in) :: phi1
                      real(8), intent (in) :: phi2
                      real(8) :: t_0
                      real(8) :: tmp
                      t_0 = acos((cos(lambda2) * cos(phi1))) * r
                      if (lambda2 <= (-3.4d-8)) then
                          tmp = t_0
                      else if (lambda2 <= 3.2d-6) then
                          tmp = acos((cos(lambda1) * cos(phi1))) * r
                      else
                          tmp = t_0
                      end if
                      code = tmp
                  end function
                  
                  public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                  	double t_0 = Math.acos((Math.cos(lambda2) * Math.cos(phi1))) * R;
                  	double tmp;
                  	if (lambda2 <= -3.4e-8) {
                  		tmp = t_0;
                  	} else if (lambda2 <= 3.2e-6) {
                  		tmp = Math.acos((Math.cos(lambda1) * Math.cos(phi1))) * R;
                  	} else {
                  		tmp = t_0;
                  	}
                  	return tmp;
                  }
                  
                  def code(R, lambda1, lambda2, phi1, phi2):
                  	t_0 = math.acos((math.cos(lambda2) * math.cos(phi1))) * R
                  	tmp = 0
                  	if lambda2 <= -3.4e-8:
                  		tmp = t_0
                  	elif lambda2 <= 3.2e-6:
                  		tmp = math.acos((math.cos(lambda1) * math.cos(phi1))) * R
                  	else:
                  		tmp = t_0
                  	return tmp
                  
                  function code(R, lambda1, lambda2, phi1, phi2)
                  	t_0 = Float64(acos(Float64(cos(lambda2) * cos(phi1))) * R)
                  	tmp = 0.0
                  	if (lambda2 <= -3.4e-8)
                  		tmp = t_0;
                  	elseif (lambda2 <= 3.2e-6)
                  		tmp = Float64(acos(Float64(cos(lambda1) * cos(phi1))) * R);
                  	else
                  		tmp = t_0;
                  	end
                  	return tmp
                  end
                  
                  function tmp_2 = code(R, lambda1, lambda2, phi1, phi2)
                  	t_0 = acos((cos(lambda2) * cos(phi1))) * R;
                  	tmp = 0.0;
                  	if (lambda2 <= -3.4e-8)
                  		tmp = t_0;
                  	elseif (lambda2 <= 3.2e-6)
                  		tmp = acos((cos(lambda1) * cos(phi1))) * R;
                  	else
                  		tmp = t_0;
                  	end
                  	tmp_2 = tmp;
                  end
                  
                  code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[ArcCos[N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[lambda2, -3.4e-8], t$95$0, If[LessEqual[lambda2, 3.2e-6], N[(N[ArcCos[N[(N[Cos[lambda1], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], t$95$0]]]
                  
                  \begin{array}{l}
                  
                  \\
                  \begin{array}{l}
                  t_0 := \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R\\
                  \mathbf{if}\;\lambda_2 \leq -3.4 \cdot 10^{-8}:\\
                  \;\;\;\;t\_0\\
                  
                  \mathbf{elif}\;\lambda_2 \leq 3.2 \cdot 10^{-6}:\\
                  \;\;\;\;\cos^{-1} \left(\cos \lambda_1 \cdot \cos \phi_1\right) \cdot R\\
                  
                  \mathbf{else}:\\
                  \;\;\;\;t\_0\\
                  
                  
                  \end{array}
                  \end{array}
                  
                  Derivation
                  1. Split input into 2 regimes
                  2. if lambda2 < -3.4e-8 or 3.1999999999999999e-6 < lambda2

                    1. Initial program 60.7%

                      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                    2. Taylor expanded in phi2 around 0

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                    3. Step-by-step derivation
                      1. *-commutativeN/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                      2. lower-*.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                      3. lift-cos.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                      4. lift--.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      5. lift-cos.f6439.7

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                    4. Applied rewrites39.7%

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                    5. Taylor expanded in lambda1 around 0

                      \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)}\right) \cdot R \]
                    6. Step-by-step derivation
                      1. cos-neg-revN/A

                        \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \cos \lambda_2\right) \cdot R \]
                      2. *-commutativeN/A

                        \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R \]
                      3. lower-*.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R \]
                      4. lift-cos.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R \]
                      5. lift-cos.f6439.5

                        \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R \]
                    7. Applied rewrites39.5%

                      \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]

                    if -3.4e-8 < lambda2 < 3.1999999999999999e-6

                    1. Initial program 88.4%

                      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                    2. Taylor expanded in phi2 around 0

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                    3. Step-by-step derivation
                      1. *-commutativeN/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                      2. lower-*.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                      3. lift-cos.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                      4. lift--.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      5. lift-cos.f6446.9

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                    4. Applied rewrites46.9%

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                    5. Taylor expanded in lambda1 around inf

                      \[\leadsto \cos^{-1} \left(\cos \lambda_1 \cdot \cos \phi_1\right) \cdot R \]
                    6. Step-by-step derivation
                      1. Applied rewrites46.9%

                        \[\leadsto \cos^{-1} \left(\cos \lambda_1 \cdot \cos \phi_1\right) \cdot R \]
                    7. Recombined 2 regimes into one program.
                    8. Add Preprocessing

                    Alternative 23: 32.4% accurate, 2.3× speedup?

                    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\phi_1 \leq -5.5 \cdot 10^{-6}:\\ \;\;\;\;\cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R\\ \end{array} \end{array} \]
                    (FPCore (R lambda1 lambda2 phi1 phi2)
                     :precision binary64
                     (if (<= phi1 -5.5e-6)
                       (* (acos (* (cos lambda2) (cos phi1))) R)
                       (* (acos (cos (- lambda1 lambda2))) R)))
                    double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                    	double tmp;
                    	if (phi1 <= -5.5e-6) {
                    		tmp = acos((cos(lambda2) * cos(phi1))) * R;
                    	} else {
                    		tmp = acos(cos((lambda1 - lambda2))) * R;
                    	}
                    	return tmp;
                    }
                    
                    module fmin_fmax_functions
                        implicit none
                        private
                        public fmax
                        public fmin
                    
                        interface fmax
                            module procedure fmax88
                            module procedure fmax44
                            module procedure fmax84
                            module procedure fmax48
                        end interface
                        interface fmin
                            module procedure fmin88
                            module procedure fmin44
                            module procedure fmin84
                            module procedure fmin48
                        end interface
                    contains
                        real(8) function fmax88(x, y) result (res)
                            real(8), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                        end function
                        real(4) function fmax44(x, y) result (res)
                            real(4), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                        end function
                        real(8) function fmax84(x, y) result(res)
                            real(8), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
                        end function
                        real(8) function fmax48(x, y) result(res)
                            real(4), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
                        end function
                        real(8) function fmin88(x, y) result (res)
                            real(8), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                        end function
                        real(4) function fmin44(x, y) result (res)
                            real(4), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                        end function
                        real(8) function fmin84(x, y) result(res)
                            real(8), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
                        end function
                        real(8) function fmin48(x, y) result(res)
                            real(4), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
                        end function
                    end module
                    
                    real(8) function code(r, lambda1, lambda2, phi1, phi2)
                    use fmin_fmax_functions
                        real(8), intent (in) :: r
                        real(8), intent (in) :: lambda1
                        real(8), intent (in) :: lambda2
                        real(8), intent (in) :: phi1
                        real(8), intent (in) :: phi2
                        real(8) :: tmp
                        if (phi1 <= (-5.5d-6)) then
                            tmp = acos((cos(lambda2) * cos(phi1))) * r
                        else
                            tmp = acos(cos((lambda1 - lambda2))) * r
                        end if
                        code = tmp
                    end function
                    
                    public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                    	double tmp;
                    	if (phi1 <= -5.5e-6) {
                    		tmp = Math.acos((Math.cos(lambda2) * Math.cos(phi1))) * R;
                    	} else {
                    		tmp = Math.acos(Math.cos((lambda1 - lambda2))) * R;
                    	}
                    	return tmp;
                    }
                    
                    def code(R, lambda1, lambda2, phi1, phi2):
                    	tmp = 0
                    	if phi1 <= -5.5e-6:
                    		tmp = math.acos((math.cos(lambda2) * math.cos(phi1))) * R
                    	else:
                    		tmp = math.acos(math.cos((lambda1 - lambda2))) * R
                    	return tmp
                    
                    function code(R, lambda1, lambda2, phi1, phi2)
                    	tmp = 0.0
                    	if (phi1 <= -5.5e-6)
                    		tmp = Float64(acos(Float64(cos(lambda2) * cos(phi1))) * R);
                    	else
                    		tmp = Float64(acos(cos(Float64(lambda1 - lambda2))) * R);
                    	end
                    	return tmp
                    end
                    
                    function tmp_2 = code(R, lambda1, lambda2, phi1, phi2)
                    	tmp = 0.0;
                    	if (phi1 <= -5.5e-6)
                    		tmp = acos((cos(lambda2) * cos(phi1))) * R;
                    	else
                    		tmp = acos(cos((lambda1 - lambda2))) * R;
                    	end
                    	tmp_2 = tmp;
                    end
                    
                    code[R_, lambda1_, lambda2_, phi1_, phi2_] := If[LessEqual[phi1, -5.5e-6], N[(N[ArcCos[N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[phi1], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]
                    
                    \begin{array}{l}
                    
                    \\
                    \begin{array}{l}
                    \mathbf{if}\;\phi_1 \leq -5.5 \cdot 10^{-6}:\\
                    \;\;\;\;\cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R\\
                    
                    \mathbf{else}:\\
                    \;\;\;\;\cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R\\
                    
                    
                    \end{array}
                    \end{array}
                    
                    Derivation
                    1. Split input into 2 regimes
                    2. if phi1 < -5.4999999999999999e-6

                      1. Initial program 78.7%

                        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                      2. Taylor expanded in phi2 around 0

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                      3. Step-by-step derivation
                        1. *-commutativeN/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        2. lower-*.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        3. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                        4. lift--.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                        5. lift-cos.f6448.3

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      4. Applied rewrites48.3%

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                      5. Taylor expanded in lambda1 around 0

                        \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \color{blue}{\cos \left(\mathsf{neg}\left(\lambda_2\right)\right)}\right) \cdot R \]
                      6. Step-by-step derivation
                        1. cos-neg-revN/A

                          \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \cos \lambda_2\right) \cdot R \]
                        2. *-commutativeN/A

                          \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R \]
                        3. lower-*.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R \]
                        4. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R \]
                        5. lift-cos.f6438.7

                          \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \cos \phi_1\right) \cdot R \]
                      7. Applied rewrites38.7%

                        \[\leadsto \cos^{-1} \left(\cos \lambda_2 \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]

                      if -5.4999999999999999e-6 < phi1

                      1. Initial program 72.5%

                        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                      2. Taylor expanded in phi2 around 0

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                      3. Step-by-step derivation
                        1. *-commutativeN/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        2. lower-*.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        3. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                        4. lift--.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                        5. lift-cos.f6441.4

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      4. Applied rewrites41.4%

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                      5. Taylor expanded in phi1 around 0

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      6. Step-by-step derivation
                        1. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                        2. lift--.f6430.2

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      7. Applied rewrites30.2%

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                    3. Recombined 2 regimes into one program.
                    4. Add Preprocessing

                    Alternative 24: 26.6% accurate, 4.3× speedup?

                    \[\begin{array}{l} \\ \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \end{array} \]
                    (FPCore (R lambda1 lambda2 phi1 phi2)
                     :precision binary64
                     (* (acos (cos (- lambda1 lambda2))) R))
                    double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                    	return acos(cos((lambda1 - lambda2))) * R;
                    }
                    
                    module fmin_fmax_functions
                        implicit none
                        private
                        public fmax
                        public fmin
                    
                        interface fmax
                            module procedure fmax88
                            module procedure fmax44
                            module procedure fmax84
                            module procedure fmax48
                        end interface
                        interface fmin
                            module procedure fmin88
                            module procedure fmin44
                            module procedure fmin84
                            module procedure fmin48
                        end interface
                    contains
                        real(8) function fmax88(x, y) result (res)
                            real(8), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                        end function
                        real(4) function fmax44(x, y) result (res)
                            real(4), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                        end function
                        real(8) function fmax84(x, y) result(res)
                            real(8), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
                        end function
                        real(8) function fmax48(x, y) result(res)
                            real(4), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
                        end function
                        real(8) function fmin88(x, y) result (res)
                            real(8), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                        end function
                        real(4) function fmin44(x, y) result (res)
                            real(4), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                        end function
                        real(8) function fmin84(x, y) result(res)
                            real(8), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
                        end function
                        real(8) function fmin48(x, y) result(res)
                            real(4), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
                        end function
                    end module
                    
                    real(8) function code(r, lambda1, lambda2, phi1, phi2)
                    use fmin_fmax_functions
                        real(8), intent (in) :: r
                        real(8), intent (in) :: lambda1
                        real(8), intent (in) :: lambda2
                        real(8), intent (in) :: phi1
                        real(8), intent (in) :: phi2
                        code = acos(cos((lambda1 - lambda2))) * r
                    end function
                    
                    public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                    	return Math.acos(Math.cos((lambda1 - lambda2))) * R;
                    }
                    
                    def code(R, lambda1, lambda2, phi1, phi2):
                    	return math.acos(math.cos((lambda1 - lambda2))) * R
                    
                    function code(R, lambda1, lambda2, phi1, phi2)
                    	return Float64(acos(cos(Float64(lambda1 - lambda2))) * R)
                    end
                    
                    function tmp = code(R, lambda1, lambda2, phi1, phi2)
                    	tmp = acos(cos((lambda1 - lambda2))) * R;
                    end
                    
                    code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
                    
                    \begin{array}{l}
                    
                    \\
                    \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R
                    \end{array}
                    
                    Derivation
                    1. Initial program 74.2%

                      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                    2. Taylor expanded in phi2 around 0

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                    3. Step-by-step derivation
                      1. *-commutativeN/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                      2. lower-*.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                      3. lift-cos.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                      4. lift--.f64N/A

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      5. lift-cos.f6443.2

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                    4. Applied rewrites43.2%

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                    5. Taylor expanded in phi1 around 0

                      \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                    6. Step-by-step derivation
                      1. lift-cos.f64N/A

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      2. lift--.f6426.6

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                    7. Applied rewrites26.6%

                      \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                    8. Add Preprocessing

                    Alternative 25: 26.5% accurate, 3.8× speedup?

                    \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \cos \lambda_2 \cdot R\\ \mathbf{if}\;\lambda_2 \leq -0.00023:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\lambda_2 \leq 3.2 \cdot 10^{-6}:\\ \;\;\;\;\cos^{-1} \cos \lambda_1 \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
                    (FPCore (R lambda1 lambda2 phi1 phi2)
                     :precision binary64
                     (let* ((t_0 (* (acos (cos lambda2)) R)))
                       (if (<= lambda2 -0.00023)
                         t_0
                         (if (<= lambda2 3.2e-6) (* (acos (cos lambda1)) R) t_0))))
                    double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                    	double t_0 = acos(cos(lambda2)) * R;
                    	double tmp;
                    	if (lambda2 <= -0.00023) {
                    		tmp = t_0;
                    	} else if (lambda2 <= 3.2e-6) {
                    		tmp = acos(cos(lambda1)) * R;
                    	} else {
                    		tmp = t_0;
                    	}
                    	return tmp;
                    }
                    
                    module fmin_fmax_functions
                        implicit none
                        private
                        public fmax
                        public fmin
                    
                        interface fmax
                            module procedure fmax88
                            module procedure fmax44
                            module procedure fmax84
                            module procedure fmax48
                        end interface
                        interface fmin
                            module procedure fmin88
                            module procedure fmin44
                            module procedure fmin84
                            module procedure fmin48
                        end interface
                    contains
                        real(8) function fmax88(x, y) result (res)
                            real(8), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                        end function
                        real(4) function fmax44(x, y) result (res)
                            real(4), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                        end function
                        real(8) function fmax84(x, y) result(res)
                            real(8), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
                        end function
                        real(8) function fmax48(x, y) result(res)
                            real(4), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
                        end function
                        real(8) function fmin88(x, y) result (res)
                            real(8), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                        end function
                        real(4) function fmin44(x, y) result (res)
                            real(4), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                        end function
                        real(8) function fmin84(x, y) result(res)
                            real(8), intent (in) :: x
                            real(4), intent (in) :: y
                            res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
                        end function
                        real(8) function fmin48(x, y) result(res)
                            real(4), intent (in) :: x
                            real(8), intent (in) :: y
                            res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
                        end function
                    end module
                    
                    real(8) function code(r, lambda1, lambda2, phi1, phi2)
                    use fmin_fmax_functions
                        real(8), intent (in) :: r
                        real(8), intent (in) :: lambda1
                        real(8), intent (in) :: lambda2
                        real(8), intent (in) :: phi1
                        real(8), intent (in) :: phi2
                        real(8) :: t_0
                        real(8) :: tmp
                        t_0 = acos(cos(lambda2)) * r
                        if (lambda2 <= (-0.00023d0)) then
                            tmp = t_0
                        else if (lambda2 <= 3.2d-6) then
                            tmp = acos(cos(lambda1)) * r
                        else
                            tmp = t_0
                        end if
                        code = tmp
                    end function
                    
                    public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                    	double t_0 = Math.acos(Math.cos(lambda2)) * R;
                    	double tmp;
                    	if (lambda2 <= -0.00023) {
                    		tmp = t_0;
                    	} else if (lambda2 <= 3.2e-6) {
                    		tmp = Math.acos(Math.cos(lambda1)) * R;
                    	} else {
                    		tmp = t_0;
                    	}
                    	return tmp;
                    }
                    
                    def code(R, lambda1, lambda2, phi1, phi2):
                    	t_0 = math.acos(math.cos(lambda2)) * R
                    	tmp = 0
                    	if lambda2 <= -0.00023:
                    		tmp = t_0
                    	elif lambda2 <= 3.2e-6:
                    		tmp = math.acos(math.cos(lambda1)) * R
                    	else:
                    		tmp = t_0
                    	return tmp
                    
                    function code(R, lambda1, lambda2, phi1, phi2)
                    	t_0 = Float64(acos(cos(lambda2)) * R)
                    	tmp = 0.0
                    	if (lambda2 <= -0.00023)
                    		tmp = t_0;
                    	elseif (lambda2 <= 3.2e-6)
                    		tmp = Float64(acos(cos(lambda1)) * R);
                    	else
                    		tmp = t_0;
                    	end
                    	return tmp
                    end
                    
                    function tmp_2 = code(R, lambda1, lambda2, phi1, phi2)
                    	t_0 = acos(cos(lambda2)) * R;
                    	tmp = 0.0;
                    	if (lambda2 <= -0.00023)
                    		tmp = t_0;
                    	elseif (lambda2 <= 3.2e-6)
                    		tmp = acos(cos(lambda1)) * R;
                    	else
                    		tmp = t_0;
                    	end
                    	tmp_2 = tmp;
                    end
                    
                    code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[ArcCos[N[Cos[lambda2], $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[lambda2, -0.00023], t$95$0, If[LessEqual[lambda2, 3.2e-6], N[(N[ArcCos[N[Cos[lambda1], $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], t$95$0]]]
                    
                    \begin{array}{l}
                    
                    \\
                    \begin{array}{l}
                    t_0 := \cos^{-1} \cos \lambda_2 \cdot R\\
                    \mathbf{if}\;\lambda_2 \leq -0.00023:\\
                    \;\;\;\;t\_0\\
                    
                    \mathbf{elif}\;\lambda_2 \leq 3.2 \cdot 10^{-6}:\\
                    \;\;\;\;\cos^{-1} \cos \lambda_1 \cdot R\\
                    
                    \mathbf{else}:\\
                    \;\;\;\;t\_0\\
                    
                    
                    \end{array}
                    \end{array}
                    
                    Derivation
                    1. Split input into 2 regimes
                    2. if lambda2 < -2.3000000000000001e-4 or 3.1999999999999999e-6 < lambda2

                      1. Initial program 60.7%

                        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                      2. Taylor expanded in phi2 around 0

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                      3. Step-by-step derivation
                        1. *-commutativeN/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        2. lower-*.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        3. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                        4. lift--.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                        5. lift-cos.f6439.7

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      4. Applied rewrites39.7%

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                      5. Taylor expanded in phi1 around 0

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      6. Step-by-step derivation
                        1. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                        2. lift--.f6429.4

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      7. Applied rewrites29.4%

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      8. Taylor expanded in lambda1 around 0

                        \[\leadsto \cos^{-1} \cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot R \]
                      9. Step-by-step derivation
                        1. cos-neg-revN/A

                          \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                        2. lift-cos.f6429.3

                          \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                      10. Applied rewrites29.3%

                        \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]

                      if -2.3000000000000001e-4 < lambda2 < 3.1999999999999999e-6

                      1. Initial program 88.3%

                        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                      2. Taylor expanded in phi2 around 0

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                      3. Step-by-step derivation
                        1. *-commutativeN/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        2. lower-*.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        3. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                        4. lift--.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                        5. lift-cos.f6446.9

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      4. Applied rewrites46.9%

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                      5. Taylor expanded in phi1 around 0

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      6. Step-by-step derivation
                        1. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                        2. lift--.f6423.7

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      7. Applied rewrites23.7%

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      8. Taylor expanded in lambda1 around inf

                        \[\leadsto \cos^{-1} \cos \lambda_1 \cdot R \]
                      9. Step-by-step derivation
                        1. Applied rewrites23.6%

                          \[\leadsto \cos^{-1} \cos \lambda_1 \cdot R \]
                      10. Recombined 2 regimes into one program.
                      11. Add Preprocessing

                      Alternative 26: 17.4% accurate, 4.5× speedup?

                      \[\begin{array}{l} \\ \cos^{-1} \cos \lambda_2 \cdot R \end{array} \]
                      (FPCore (R lambda1 lambda2 phi1 phi2)
                       :precision binary64
                       (* (acos (cos lambda2)) R))
                      double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                      	return acos(cos(lambda2)) * R;
                      }
                      
                      module fmin_fmax_functions
                          implicit none
                          private
                          public fmax
                          public fmin
                      
                          interface fmax
                              module procedure fmax88
                              module procedure fmax44
                              module procedure fmax84
                              module procedure fmax48
                          end interface
                          interface fmin
                              module procedure fmin88
                              module procedure fmin44
                              module procedure fmin84
                              module procedure fmin48
                          end interface
                      contains
                          real(8) function fmax88(x, y) result (res)
                              real(8), intent (in) :: x
                              real(8), intent (in) :: y
                              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                          end function
                          real(4) function fmax44(x, y) result (res)
                              real(4), intent (in) :: x
                              real(4), intent (in) :: y
                              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                          end function
                          real(8) function fmax84(x, y) result(res)
                              real(8), intent (in) :: x
                              real(4), intent (in) :: y
                              res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
                          end function
                          real(8) function fmax48(x, y) result(res)
                              real(4), intent (in) :: x
                              real(8), intent (in) :: y
                              res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
                          end function
                          real(8) function fmin88(x, y) result (res)
                              real(8), intent (in) :: x
                              real(8), intent (in) :: y
                              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                          end function
                          real(4) function fmin44(x, y) result (res)
                              real(4), intent (in) :: x
                              real(4), intent (in) :: y
                              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                          end function
                          real(8) function fmin84(x, y) result(res)
                              real(8), intent (in) :: x
                              real(4), intent (in) :: y
                              res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
                          end function
                          real(8) function fmin48(x, y) result(res)
                              real(4), intent (in) :: x
                              real(8), intent (in) :: y
                              res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
                          end function
                      end module
                      
                      real(8) function code(r, lambda1, lambda2, phi1, phi2)
                      use fmin_fmax_functions
                          real(8), intent (in) :: r
                          real(8), intent (in) :: lambda1
                          real(8), intent (in) :: lambda2
                          real(8), intent (in) :: phi1
                          real(8), intent (in) :: phi2
                          code = acos(cos(lambda2)) * r
                      end function
                      
                      public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                      	return Math.acos(Math.cos(lambda2)) * R;
                      }
                      
                      def code(R, lambda1, lambda2, phi1, phi2):
                      	return math.acos(math.cos(lambda2)) * R
                      
                      function code(R, lambda1, lambda2, phi1, phi2)
                      	return Float64(acos(cos(lambda2)) * R)
                      end
                      
                      function tmp = code(R, lambda1, lambda2, phi1, phi2)
                      	tmp = acos(cos(lambda2)) * R;
                      end
                      
                      code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[Cos[lambda2], $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
                      
                      \begin{array}{l}
                      
                      \\
                      \cos^{-1} \cos \lambda_2 \cdot R
                      \end{array}
                      
                      Derivation
                      1. Initial program 74.2%

                        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                      2. Taylor expanded in phi2 around 0

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                      3. Step-by-step derivation
                        1. *-commutativeN/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        2. lower-*.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        3. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                        4. lift--.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                        5. lift-cos.f6443.2

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      4. Applied rewrites43.2%

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                      5. Taylor expanded in phi1 around 0

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      6. Step-by-step derivation
                        1. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                        2. lift--.f6426.6

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      7. Applied rewrites26.6%

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      8. Taylor expanded in lambda1 around 0

                        \[\leadsto \cos^{-1} \cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot R \]
                      9. Step-by-step derivation
                        1. cos-neg-revN/A

                          \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                        2. lift-cos.f6417.4

                          \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                      10. Applied rewrites17.4%

                        \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                      11. Add Preprocessing

                      Alternative 27: 4.2% accurate, 22.2× speedup?

                      \[\begin{array}{l} \\ \cos^{-1} 1 \cdot R \end{array} \]
                      (FPCore (R lambda1 lambda2 phi1 phi2) :precision binary64 (* (acos 1.0) R))
                      double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                      	return acos(1.0) * R;
                      }
                      
                      module fmin_fmax_functions
                          implicit none
                          private
                          public fmax
                          public fmin
                      
                          interface fmax
                              module procedure fmax88
                              module procedure fmax44
                              module procedure fmax84
                              module procedure fmax48
                          end interface
                          interface fmin
                              module procedure fmin88
                              module procedure fmin44
                              module procedure fmin84
                              module procedure fmin48
                          end interface
                      contains
                          real(8) function fmax88(x, y) result (res)
                              real(8), intent (in) :: x
                              real(8), intent (in) :: y
                              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                          end function
                          real(4) function fmax44(x, y) result (res)
                              real(4), intent (in) :: x
                              real(4), intent (in) :: y
                              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
                          end function
                          real(8) function fmax84(x, y) result(res)
                              real(8), intent (in) :: x
                              real(4), intent (in) :: y
                              res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
                          end function
                          real(8) function fmax48(x, y) result(res)
                              real(4), intent (in) :: x
                              real(8), intent (in) :: y
                              res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
                          end function
                          real(8) function fmin88(x, y) result (res)
                              real(8), intent (in) :: x
                              real(8), intent (in) :: y
                              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                          end function
                          real(4) function fmin44(x, y) result (res)
                              real(4), intent (in) :: x
                              real(4), intent (in) :: y
                              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
                          end function
                          real(8) function fmin84(x, y) result(res)
                              real(8), intent (in) :: x
                              real(4), intent (in) :: y
                              res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
                          end function
                          real(8) function fmin48(x, y) result(res)
                              real(4), intent (in) :: x
                              real(8), intent (in) :: y
                              res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
                          end function
                      end module
                      
                      real(8) function code(r, lambda1, lambda2, phi1, phi2)
                      use fmin_fmax_functions
                          real(8), intent (in) :: r
                          real(8), intent (in) :: lambda1
                          real(8), intent (in) :: lambda2
                          real(8), intent (in) :: phi1
                          real(8), intent (in) :: phi2
                          code = acos(1.0d0) * r
                      end function
                      
                      public static double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                      	return Math.acos(1.0) * R;
                      }
                      
                      def code(R, lambda1, lambda2, phi1, phi2):
                      	return math.acos(1.0) * R
                      
                      function code(R, lambda1, lambda2, phi1, phi2)
                      	return Float64(acos(1.0) * R)
                      end
                      
                      function tmp = code(R, lambda1, lambda2, phi1, phi2)
                      	tmp = acos(1.0) * R;
                      end
                      
                      code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[1.0], $MachinePrecision] * R), $MachinePrecision]
                      
                      \begin{array}{l}
                      
                      \\
                      \cos^{-1} 1 \cdot R
                      \end{array}
                      
                      Derivation
                      1. Initial program 74.2%

                        \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                      2. Taylor expanded in phi2 around 0

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)} \cdot R \]
                      3. Step-by-step derivation
                        1. *-commutativeN/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        2. lower-*.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \color{blue}{\cos \phi_1}\right) \cdot R \]
                        3. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \color{blue}{\phi_1}\right) \cdot R \]
                        4. lift--.f64N/A

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                        5. lift-cos.f6443.2

                          \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                      4. Applied rewrites43.2%

                        \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                      5. Taylor expanded in phi1 around 0

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      6. Step-by-step derivation
                        1. lift-cos.f64N/A

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                        2. lift--.f6426.6

                          \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      7. Applied rewrites26.6%

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                      8. Taylor expanded in lambda1 around 0

                        \[\leadsto \cos^{-1} \cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot R \]
                      9. Step-by-step derivation
                        1. cos-neg-revN/A

                          \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                        2. lift-cos.f6417.4

                          \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                      10. Applied rewrites17.4%

                        \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                      11. Taylor expanded in lambda2 around 0

                        \[\leadsto \cos^{-1} 1 \cdot R \]
                      12. Step-by-step derivation
                        1. Applied rewrites4.2%

                          \[\leadsto \cos^{-1} 1 \cdot R \]
                        2. Add Preprocessing

                        Reproduce

                        ?
                        herbie shell --seed 2025112 
                        (FPCore (R lambda1 lambda2 phi1 phi2)
                          :name "Spherical law of cosines"
                          :precision binary64
                          (* (acos (+ (* (sin phi1) (sin phi2)) (* (* (cos phi1) (cos phi2)) (cos (- lambda1 lambda2))))) R))