Spherical law of cosines

Percentage Accurate: 73.5% → 93.9%
Time: 14.1s
Alternatives: 19
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 19 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: 73.5% 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: 93.9% accurate, 0.7× 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 73.5%

    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
  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.f6493.9

      \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \color{blue}{\sin \lambda_2}\right)\right) \cdot R \]
  3. Applied rewrites93.9%

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

Alternative 2: 84.0% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\ \mathbf{if}\;\phi_1 \leq -1000:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\phi_1 \leq 7.5 \cdot 10^{-17}:\\ \;\;\;\;\cos^{-1} \left(\left(\phi_1 \cdot \mathsf{fma}\left(\phi_1 \cdot \phi_1, 0.008333333333333333 \cdot \left(\phi_1 \cdot \phi_1\right) - 0.16666666666666666, 1\right)\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (R lambda1 lambda2 phi1 phi2)
 :precision binary64
 (let* ((t_0
         (*
          (acos
           (fma
            (* (cos (- lambda1 lambda2)) (cos phi2))
            (cos phi1)
            (* (sin phi2) (sin phi1))))
          R)))
   (if (<= phi1 -1000.0)
     t_0
     (if (<= phi1 7.5e-17)
       (*
        (acos
         (+
          (*
           (*
            phi1
            (fma
             (* phi1 phi1)
             (- (* 0.008333333333333333 (* phi1 phi1)) 0.16666666666666666)
             1.0))
           (sin phi2))
          (*
           (* (cos phi1) (cos phi2))
           (fma (cos lambda1) (cos lambda2) (* (sin lambda1) (sin lambda2))))))
        R)
       t_0))))
double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
	double t_0 = acos(fma((cos((lambda1 - lambda2)) * cos(phi2)), cos(phi1), (sin(phi2) * sin(phi1)))) * R;
	double tmp;
	if (phi1 <= -1000.0) {
		tmp = t_0;
	} else if (phi1 <= 7.5e-17) {
		tmp = acos((((phi1 * fma((phi1 * phi1), ((0.008333333333333333 * (phi1 * phi1)) - 0.16666666666666666), 1.0)) * sin(phi2)) + ((cos(phi1) * cos(phi2)) * fma(cos(lambda1), cos(lambda2), (sin(lambda1) * sin(lambda2)))))) * R;
	} else {
		tmp = t_0;
	}
	return tmp;
}
function code(R, lambda1, lambda2, phi1, phi2)
	t_0 = Float64(acos(fma(Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2)), cos(phi1), Float64(sin(phi2) * sin(phi1)))) * R)
	tmp = 0.0
	if (phi1 <= -1000.0)
		tmp = t_0;
	elseif (phi1 <= 7.5e-17)
		tmp = Float64(acos(Float64(Float64(Float64(phi1 * fma(Float64(phi1 * phi1), Float64(Float64(0.008333333333333333 * Float64(phi1 * phi1)) - 0.16666666666666666), 1.0)) * sin(phi2)) + Float64(Float64(cos(phi1) * cos(phi2)) * fma(cos(lambda1), cos(lambda2), 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[ArcCos[N[(N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[phi1, -1000.0], t$95$0, If[LessEqual[phi1, 7.5e-17], N[(N[ArcCos[N[(N[(N[(phi1 * N[(N[(phi1 * phi1), $MachinePrecision] * N[(N[(0.008333333333333333 * N[(phi1 * phi1), $MachinePrecision]), $MachinePrecision] - 0.16666666666666666), $MachinePrecision] + 1.0), $MachinePrecision]), $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], t$95$0]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\
\mathbf{if}\;\phi_1 \leq -1000:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;\phi_1 \leq 7.5 \cdot 10^{-17}:\\
\;\;\;\;\cos^{-1} \left(\left(\phi_1 \cdot \mathsf{fma}\left(\phi_1 \cdot \phi_1, 0.008333333333333333 \cdot \left(\phi_1 \cdot \phi_1\right) - 0.16666666666666666, 1\right)\right) \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\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if phi1 < -1e3 or 7.49999999999999984e-17 < 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. Applied rewrites79.7%

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

      if -1e3 < phi1 < 7.49999999999999984e-17

      1. Initial program 67.2%

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

        \[\leadsto \cos^{-1} \left(\color{blue}{\left(\phi_1 \cdot \left(1 + {\phi_1}^{2} \cdot \left(\frac{1}{120} \cdot {\phi_1}^{2} - \frac{1}{6}\right)\right)\right)} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      5. Step-by-step derivation
        1. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\phi_1 \cdot \color{blue}{\left(1 + {\phi_1}^{2} \cdot \left(\frac{1}{120} \cdot {\phi_1}^{2} - \frac{1}{6}\right)\right)}\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
        2. +-commutativeN/A

          \[\leadsto \cos^{-1} \left(\left(\phi_1 \cdot \left({\phi_1}^{2} \cdot \left(\frac{1}{120} \cdot {\phi_1}^{2} - \frac{1}{6}\right) + \color{blue}{1}\right)\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
        3. lower-fma.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\phi_1 \cdot \mathsf{fma}\left({\phi_1}^{2}, \color{blue}{\frac{1}{120} \cdot {\phi_1}^{2} - \frac{1}{6}}, 1\right)\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
        4. unpow2N/A

          \[\leadsto \cos^{-1} \left(\left(\phi_1 \cdot \mathsf{fma}\left(\phi_1 \cdot \phi_1, \color{blue}{\frac{1}{120} \cdot {\phi_1}^{2}} - \frac{1}{6}, 1\right)\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
        5. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\phi_1 \cdot \mathsf{fma}\left(\phi_1 \cdot \phi_1, \color{blue}{\frac{1}{120} \cdot {\phi_1}^{2}} - \frac{1}{6}, 1\right)\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
        6. lower--.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\phi_1 \cdot \mathsf{fma}\left(\phi_1 \cdot \phi_1, \frac{1}{120} \cdot {\phi_1}^{2} - \color{blue}{\frac{1}{6}}, 1\right)\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
        7. lower-*.f64N/A

          \[\leadsto \cos^{-1} \left(\left(\phi_1 \cdot \mathsf{fma}\left(\phi_1 \cdot \phi_1, \frac{1}{120} \cdot {\phi_1}^{2} - \frac{1}{6}, 1\right)\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
        8. unpow2N/A

          \[\leadsto \cos^{-1} \left(\left(\phi_1 \cdot \mathsf{fma}\left(\phi_1 \cdot \phi_1, \frac{1}{120} \cdot \left(\phi_1 \cdot \phi_1\right) - \frac{1}{6}, 1\right)\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
        9. lower-*.f6488.5

          \[\leadsto \cos^{-1} \left(\left(\phi_1 \cdot \mathsf{fma}\left(\phi_1 \cdot \phi_1, 0.008333333333333333 \cdot \left(\phi_1 \cdot \phi_1\right) - 0.16666666666666666, 1\right)\right) \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
      6. Applied rewrites88.5%

        \[\leadsto \cos^{-1} \left(\color{blue}{\left(\phi_1 \cdot \mathsf{fma}\left(\phi_1 \cdot \phi_1, 0.008333333333333333 \cdot \left(\phi_1 \cdot \phi_1\right) - 0.16666666666666666, 1\right)\right)} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
    3. Recombined 2 regimes into one program.
    4. Add Preprocessing

    Alternative 3: 84.0% accurate, 0.7× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\ \mathbf{if}\;\phi_1 \leq -1000:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\phi_1 \leq 7.5 \cdot 10^{-17}:\\ \;\;\;\;\cos^{-1} \left(\phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
    (FPCore (R lambda1 lambda2 phi1 phi2)
     :precision binary64
     (let* ((t_0
             (*
              (acos
               (fma
                (* (cos (- lambda1 lambda2)) (cos phi2))
                (cos phi1)
                (* (sin phi2) (sin phi1))))
              R)))
       (if (<= phi1 -1000.0)
         t_0
         (if (<= phi1 7.5e-17)
           (*
            (acos
             (+
              (* phi1 (sin phi2))
              (*
               (* (cos phi1) (cos phi2))
               (fma (cos lambda1) (cos lambda2) (* (sin lambda1) (sin lambda2))))))
            R)
           t_0))))
    double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
    	double t_0 = acos(fma((cos((lambda1 - lambda2)) * cos(phi2)), cos(phi1), (sin(phi2) * sin(phi1)))) * R;
    	double tmp;
    	if (phi1 <= -1000.0) {
    		tmp = t_0;
    	} else if (phi1 <= 7.5e-17) {
    		tmp = acos(((phi1 * sin(phi2)) + ((cos(phi1) * cos(phi2)) * fma(cos(lambda1), cos(lambda2), (sin(lambda1) * sin(lambda2)))))) * R;
    	} else {
    		tmp = t_0;
    	}
    	return tmp;
    }
    
    function code(R, lambda1, lambda2, phi1, phi2)
    	t_0 = Float64(acos(fma(Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2)), cos(phi1), Float64(sin(phi2) * sin(phi1)))) * R)
    	tmp = 0.0
    	if (phi1 <= -1000.0)
    		tmp = t_0;
    	elseif (phi1 <= 7.5e-17)
    		tmp = Float64(acos(Float64(Float64(phi1 * sin(phi2)) + Float64(Float64(cos(phi1) * cos(phi2)) * fma(cos(lambda1), cos(lambda2), 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[ArcCos[N[(N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[phi1, -1000.0], t$95$0, If[LessEqual[phi1, 7.5e-17], N[(N[ArcCos[N[(N[(phi1 * 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], t$95$0]]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_0 := \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\
    \mathbf{if}\;\phi_1 \leq -1000:\\
    \;\;\;\;t\_0\\
    
    \mathbf{elif}\;\phi_1 \leq 7.5 \cdot 10^{-17}:\\
    \;\;\;\;\cos^{-1} \left(\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\\
    
    \mathbf{else}:\\
    \;\;\;\;t\_0\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if phi1 < -1e3 or 7.49999999999999984e-17 < 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. Applied rewrites79.7%

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

        if -1e3 < phi1 < 7.49999999999999984e-17

        1. Initial program 67.2%

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

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

            \[\leadsto \cos^{-1} \left(\color{blue}{\phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right) \cdot R \]
        6. Recombined 2 regimes into one program.
        7. Add Preprocessing

        Alternative 4: 84.0% accurate, 0.7× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\ \mathbf{if}\;\phi_1 \leq -2.15 \cdot 10^{-6}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\phi_1 \leq 7.5 \cdot 10^{-17}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \phi_2 \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
        (FPCore (R lambda1 lambda2 phi1 phi2)
         :precision binary64
         (let* ((t_0
                 (*
                  (acos
                   (fma
                    (* (cos (- lambda1 lambda2)) (cos phi2))
                    (cos phi1)
                    (* (sin phi2) (sin phi1))))
                  R)))
           (if (<= phi1 -2.15e-6)
             t_0
             (if (<= phi1 7.5e-17)
               (*
                (acos
                 (fma
                  (sin phi2)
                  (sin phi1)
                  (*
                   (cos phi2)
                   (fma (cos lambda1) (cos lambda2) (* (sin lambda1) (sin lambda2))))))
                R)
               t_0))))
        double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
        	double t_0 = acos(fma((cos((lambda1 - lambda2)) * cos(phi2)), cos(phi1), (sin(phi2) * sin(phi1)))) * R;
        	double tmp;
        	if (phi1 <= -2.15e-6) {
        		tmp = t_0;
        	} else if (phi1 <= 7.5e-17) {
        		tmp = acos(fma(sin(phi2), sin(phi1), (cos(phi2) * fma(cos(lambda1), cos(lambda2), (sin(lambda1) * sin(lambda2)))))) * R;
        	} else {
        		tmp = t_0;
        	}
        	return tmp;
        }
        
        function code(R, lambda1, lambda2, phi1, phi2)
        	t_0 = Float64(acos(fma(Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2)), cos(phi1), Float64(sin(phi2) * sin(phi1)))) * R)
        	tmp = 0.0
        	if (phi1 <= -2.15e-6)
        		tmp = t_0;
        	elseif (phi1 <= 7.5e-17)
        		tmp = Float64(acos(fma(sin(phi2), sin(phi1), Float64(cos(phi2) * fma(cos(lambda1), cos(lambda2), 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[ArcCos[N[(N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[phi1, -2.15e-6], t$95$0, If[LessEqual[phi1, 7.5e-17], N[(N[ArcCos[N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $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], t$95$0]]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_0 := \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\
        \mathbf{if}\;\phi_1 \leq -2.15 \cdot 10^{-6}:\\
        \;\;\;\;t\_0\\
        
        \mathbf{elif}\;\phi_1 \leq 7.5 \cdot 10^{-17}:\\
        \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \phi_2 \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \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 phi1 < -2.15000000000000017e-6 or 7.49999999999999984e-17 < 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. Applied rewrites79.7%

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

            if -2.15000000000000017e-6 < phi1 < 7.49999999999999984e-17

            1. Initial program 67.0%

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

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\cos \phi_2} \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            3. Step-by-step derivation
              1. lift-cos.f6467.0

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            4. Applied rewrites67.0%

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

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

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

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

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

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

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

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\sin \phi_2}, \sin \phi_1, \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
              8. lift-sin.f6467.0

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \color{blue}{\sin \phi_1}, \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
            6. Applied rewrites67.0%

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

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

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

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

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

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

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

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

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \phi_2 \cdot \mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \color{blue}{\sin \lambda_1} \cdot \sin \lambda_2\right)\right)\right) \cdot R \]
              9. lift-sin.f6488.6

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

              \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \phi_2 \cdot \color{blue}{\mathsf{fma}\left(\cos \lambda_1, \cos \lambda_2, \sin \lambda_1 \cdot \sin \lambda_2\right)}\right)\right) \cdot R \]
          3. Recombined 2 regimes into one program.
          4. Add Preprocessing

          Alternative 5: 73.2% accurate, 1.0× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\ \mathbf{if}\;\lambda_2 \leq -6:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\lambda_2 \leq 0.016:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \lambda_1 \cdot \left(\cos \phi_1 \cdot \cos \phi_2\right)\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
          (FPCore (R lambda1 lambda2 phi1 phi2)
           :precision binary64
           (let* ((t_0
                   (*
                    (acos
                     (fma
                      (* (cos lambda2) (cos phi2))
                      (cos phi1)
                      (* (sin phi2) (sin phi1))))
                    R)))
             (if (<= lambda2 -6.0)
               t_0
               (if (<= lambda2 0.016)
                 (*
                  (acos
                   (fma
                    (sin phi2)
                    (sin phi1)
                    (* (cos lambda1) (* (cos phi1) (cos phi2)))))
                  R)
                 t_0))))
          double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
          	double t_0 = acos(fma((cos(lambda2) * cos(phi2)), cos(phi1), (sin(phi2) * sin(phi1)))) * R;
          	double tmp;
          	if (lambda2 <= -6.0) {
          		tmp = t_0;
          	} else if (lambda2 <= 0.016) {
          		tmp = acos(fma(sin(phi2), sin(phi1), (cos(lambda1) * (cos(phi1) * cos(phi2))))) * R;
          	} else {
          		tmp = t_0;
          	}
          	return tmp;
          }
          
          function code(R, lambda1, lambda2, phi1, phi2)
          	t_0 = Float64(acos(fma(Float64(cos(lambda2) * cos(phi2)), cos(phi1), Float64(sin(phi2) * sin(phi1)))) * R)
          	tmp = 0.0
          	if (lambda2 <= -6.0)
          		tmp = t_0;
          	elseif (lambda2 <= 0.016)
          		tmp = Float64(acos(fma(sin(phi2), sin(phi1), Float64(cos(lambda1) * Float64(cos(phi1) * cos(phi2))))) * R);
          	else
          		tmp = t_0;
          	end
          	return tmp
          end
          
          code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[(N[ArcCos[N[(N[(N[Cos[lambda2], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[lambda2, -6.0], t$95$0, If[LessEqual[lambda2, 0.016], N[(N[ArcCos[N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision] + N[(N[Cos[lambda1], $MachinePrecision] * N[(N[Cos[phi1], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], t$95$0]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_0 := \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\\
          \mathbf{if}\;\lambda_2 \leq -6:\\
          \;\;\;\;t\_0\\
          
          \mathbf{elif}\;\lambda_2 \leq 0.016:\\
          \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \lambda_1 \cdot \left(\cos \phi_1 \cdot \cos \phi_2\right)\right)\right) \cdot R\\
          
          \mathbf{else}:\\
          \;\;\;\;t\_0\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if lambda2 < -6 or 0.016 < lambda2

            1. Initial program 59.9%

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

              \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right)\right) + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
            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.f6459.7

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
            4. Applied rewrites59.7%

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

            if -6 < lambda2 < 0.016

            1. Initial program 87.6%

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

              \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\cos \phi_2} \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            3. Step-by-step derivation
              1. lift-cos.f6445.6

                \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            4. Applied rewrites45.6%

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

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

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

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

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

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

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

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\sin \phi_2}, \sin \phi_1, \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
              8. lift-sin.f6445.6

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \color{blue}{\sin \phi_1}, \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
            6. Applied rewrites45.6%

              \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right)} \cdot R \]
            7. Taylor expanded in lambda2 around 0

              \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\cos \lambda_1 \cdot \left(\cos \phi_1 \cdot \cos \phi_2\right)}\right)\right) \cdot R \]
            8. Step-by-step derivation
              1. sin-+PI/2-revN/A

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

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

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

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

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \lambda_1 \cdot \left(\cos \phi_1 \cdot \cos \phi_2\right)\right)\right) \cdot R \]
              6. lift-*.f6487.1

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \lambda_1 \cdot \left(\cos \phi_1 \cdot \color{blue}{\cos \phi_2}\right)\right)\right) \cdot R \]
            9. Applied rewrites87.1%

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

          Alternative 6: 73.2% accurate, 1.0× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \sin \phi_2 \cdot \sin \phi_1\\ t_1 := \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, t\_0\right)\right) \cdot R\\ \mathbf{if}\;\lambda_2 \leq -6:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;\lambda_2 \leq 0.016:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, t\_0\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
          (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 -6.0)
               t_1
               (if (<= lambda2 0.016)
                 (* (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 <= -6.0) {
          		tmp = t_1;
          	} else if (lambda2 <= 0.016) {
          		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 <= -6.0)
          		tmp = t_1;
          	elseif (lambda2 <= 0.016)
          		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, -6.0], t$95$1, If[LessEqual[lambda2, 0.016], 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 -6:\\
          \;\;\;\;t\_1\\
          
          \mathbf{elif}\;\lambda_2 \leq 0.016:\\
          \;\;\;\;\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 < -6 or 0.016 < lambda2

            1. Initial program 59.9%

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

              \[\leadsto \cos^{-1} \color{blue}{\left(\cos \phi_1 \cdot \left(\cos \phi_2 \cdot \cos \left(\mathsf{neg}\left(\lambda_2\right)\right)\right) + \sin \phi_1 \cdot \sin \phi_2\right)} \cdot R \]
            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.f6459.7

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_2 \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
            4. Applied rewrites59.7%

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

            if -6 < lambda2 < 0.016

            1. Initial program 87.6%

              \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            2. Taylor expanded in 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.f6487.1

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
            4. Applied rewrites87.1%

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

          Alternative 7: 63.3% accurate, 1.0× speedup?

          \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\ \mathbf{if}\;\phi_1 \leq -0.7:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\phi_1 \leq 0.028:\\ \;\;\;\;\cos^{-1} \left(\phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
          (FPCore (R lambda1 lambda2 phi1 phi2)
           :precision binary64
           (let* ((t_0
                   (*
                    (acos
                     (fma
                      (cos lambda1)
                      (* (cos phi2) (cos phi1))
                      (* (sin phi2) (sin phi1))))
                    R)))
             (if (<= phi1 -0.7)
               t_0
               (if (<= phi1 0.028)
                 (*
                  (acos
                   (+
                    (* phi1 (sin phi2))
                    (* (* (cos phi1) (cos phi2)) (cos (- lambda1 lambda2)))))
                  R)
                 t_0))))
          double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
          	double t_0 = acos(fma(cos(lambda1), (cos(phi2) * cos(phi1)), (sin(phi2) * sin(phi1)))) * R;
          	double tmp;
          	if (phi1 <= -0.7) {
          		tmp = t_0;
          	} else if (phi1 <= 0.028) {
          		tmp = acos(((phi1 * sin(phi2)) + ((cos(phi1) * cos(phi2)) * cos((lambda1 - lambda2))))) * R;
          	} else {
          		tmp = t_0;
          	}
          	return tmp;
          }
          
          function code(R, lambda1, lambda2, phi1, phi2)
          	t_0 = Float64(acos(fma(cos(lambda1), Float64(cos(phi2) * cos(phi1)), Float64(sin(phi2) * sin(phi1)))) * R)
          	tmp = 0.0
          	if (phi1 <= -0.7)
          		tmp = t_0;
          	elseif (phi1 <= 0.028)
          		tmp = Float64(acos(Float64(Float64(phi1 * sin(phi2)) + Float64(Float64(cos(phi1) * cos(phi2)) * cos(Float64(lambda1 - lambda2))))) * R);
          	else
          		tmp = t_0;
          	end
          	return tmp
          end
          
          code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = 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]}, If[LessEqual[phi1, -0.7], t$95$0, If[LessEqual[phi1, 0.028], N[(N[ArcCos[N[(N[(phi1 * 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], t$95$0]]]
          
          \begin{array}{l}
          
          \\
          \begin{array}{l}
          t_0 := \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{if}\;\phi_1 \leq -0.7:\\
          \;\;\;\;t\_0\\
          
          \mathbf{elif}\;\phi_1 \leq 0.028:\\
          \;\;\;\;\cos^{-1} \left(\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\\
          
          \mathbf{else}:\\
          \;\;\;\;t\_0\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if phi1 < -0.69999999999999996 or 0.0280000000000000006 < phi1

            1. Initial program 79.9%

              \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            2. Taylor expanded in 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.f6459.5

                \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \lambda_1, \cos \phi_2 \cdot \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \]
            4. Applied rewrites59.5%

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

            if -0.69999999999999996 < phi1 < 0.0280000000000000006

            1. Initial program 67.2%

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

              \[\leadsto \cos^{-1} \left(\color{blue}{\phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            3. Step-by-step derivation
              1. Applied rewrites67.0%

                \[\leadsto \cos^{-1} \left(\color{blue}{\phi_1} \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            4. Recombined 2 regimes into one program.
            5. Add Preprocessing

            Alternative 8: 73.5% accurate, 1.0× speedup?

            \[\begin{array}{l} \\ \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R \end{array} \]
            (FPCore (R lambda1 lambda2 phi1 phi2)
             :precision binary64
             (*
              (acos
               (fma
                (* (cos (- lambda1 lambda2)) (cos phi2))
                (cos phi1)
                (* (sin phi2) (sin phi1))))
              R))
            double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
            	return acos(fma((cos((lambda1 - lambda2)) * cos(phi2)), cos(phi1), (sin(phi2) * sin(phi1)))) * R;
            }
            
            function code(R, lambda1, lambda2, phi1, phi2)
            	return Float64(acos(fma(Float64(cos(Float64(lambda1 - lambda2)) * cos(phi2)), cos(phi1), Float64(sin(phi2) * sin(phi1)))) * R)
            end
            
            code[R_, lambda1_, lambda2_, phi1_, phi2_] := N[(N[ArcCos[N[(N[(N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision] * N[Cos[phi2], $MachinePrecision]), $MachinePrecision] * N[Cos[phi1], $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]
            
            \begin{array}{l}
            
            \\
            \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2, \cos \phi_1, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R
            \end{array}
            
            Derivation
            1. Initial program 73.5%

              \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
            2. Step-by-step derivation
              1. Applied rewrites73.5%

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

              Alternative 9: 73.5% 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 73.5%

                \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
              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 rewrites73.5%

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

              Alternative 10: 50.0% accurate, 1.2× speedup?

              \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\lambda_1 - \lambda_2\right)\\ \mathbf{if}\;\phi_2 \leq 1550:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \phi_1 \cdot t\_0\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(t\_0, \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\ \end{array} \end{array} \]
              (FPCore (R lambda1 lambda2 phi1 phi2)
               :precision binary64
               (let* ((t_0 (cos (- lambda1 lambda2))))
                 (if (<= phi2 1550.0)
                   (* (acos (fma (sin phi2) (sin phi1) (* (cos phi1) t_0))) R)
                   (* (acos (fma t_0 (cos phi2) (* (sin phi2) (sin phi1)))) R))))
              double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
              	double t_0 = cos((lambda1 - lambda2));
              	double tmp;
              	if (phi2 <= 1550.0) {
              		tmp = acos(fma(sin(phi2), sin(phi1), (cos(phi1) * t_0))) * R;
              	} else {
              		tmp = acos(fma(t_0, cos(phi2), (sin(phi2) * sin(phi1)))) * R;
              	}
              	return tmp;
              }
              
              function code(R, lambda1, lambda2, phi1, phi2)
              	t_0 = cos(Float64(lambda1 - lambda2))
              	tmp = 0.0
              	if (phi2 <= 1550.0)
              		tmp = Float64(acos(fma(sin(phi2), sin(phi1), Float64(cos(phi1) * t_0))) * R);
              	else
              		tmp = Float64(acos(fma(t_0, cos(phi2), Float64(sin(phi2) * sin(phi1)))) * R);
              	end
              	return tmp
              end
              
              code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[phi2, 1550.0], N[(N[ArcCos[N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision] + N[(N[Cos[phi1], $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], N[(N[ArcCos[N[(t$95$0 * N[Cos[phi2], $MachinePrecision] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]
              
              \begin{array}{l}
              
              \\
              \begin{array}{l}
              t_0 := \cos \left(\lambda_1 - \lambda_2\right)\\
              \mathbf{if}\;\phi_2 \leq 1550:\\
              \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \phi_1 \cdot t\_0\right)\right) \cdot R\\
              
              \mathbf{else}:\\
              \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(t\_0, \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\
              
              
              \end{array}
              \end{array}
              
              Derivation
              1. Split input into 2 regimes
              2. if phi2 < 1550

                1. Initial program 72.0%

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

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\cos \phi_2} \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                3. Step-by-step derivation
                  1. lift-cos.f6440.6

                    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                4. Applied rewrites40.6%

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

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

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

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

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

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

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

                    \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\color{blue}{\sin \phi_2}, \sin \phi_1, \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
                  8. lift-sin.f6440.6

                    \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \color{blue}{\sin \phi_1}, \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
                6. Applied rewrites40.6%

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

                  \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \color{blue}{\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)}\right)\right) \cdot R \]
                8. Step-by-step derivation
                  1. sin-+PI/2-revN/A

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

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

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

                    \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
                  5. lift--.f6450.9

                    \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\sin \phi_2, \sin \phi_1, \cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
                9. Applied rewrites50.9%

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

                if 1550 < phi2

                1. Initial program 78.0%

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

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\cos \phi_2} \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                3. Step-by-step derivation
                  1. lift-cos.f6447.4

                    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                4. Applied rewrites47.4%

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

                    \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right), \cos \phi_2, \sin \phi_2 \cdot \color{blue}{\sin \phi_1}\right)\right) \cdot R \]
                  16. lift-*.f6447.4

                    \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right), \cos \phi_2, \color{blue}{\sin \phi_2 \cdot \sin \phi_1}\right)\right) \cdot R \]
                6. Applied rewrites47.4%

                  \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right), \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]
              3. Recombined 2 regimes into one program.
              4. Add Preprocessing

              Alternative 11: 50.2% accurate, 1.2× speedup?

              \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\lambda_1 - \lambda_2\right)\\ \mathbf{if}\;\phi_2 \leq 0.145:\\ \;\;\;\;\cos^{-1} \left(t\_0 \cdot \cos \phi_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(t\_0, \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\ \end{array} \end{array} \]
              (FPCore (R lambda1 lambda2 phi1 phi2)
               :precision binary64
               (let* ((t_0 (cos (- lambda1 lambda2))))
                 (if (<= phi2 0.145)
                   (* (acos (* t_0 (cos phi1))) R)
                   (* (acos (fma t_0 (cos phi2) (* (sin phi2) (sin phi1)))) R))))
              double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
              	double t_0 = cos((lambda1 - lambda2));
              	double tmp;
              	if (phi2 <= 0.145) {
              		tmp = acos((t_0 * cos(phi1))) * R;
              	} else {
              		tmp = acos(fma(t_0, cos(phi2), (sin(phi2) * sin(phi1)))) * R;
              	}
              	return tmp;
              }
              
              function code(R, lambda1, lambda2, phi1, phi2)
              	t_0 = cos(Float64(lambda1 - lambda2))
              	tmp = 0.0
              	if (phi2 <= 0.145)
              		tmp = Float64(acos(Float64(t_0 * cos(phi1))) * R);
              	else
              		tmp = Float64(acos(fma(t_0, cos(phi2), Float64(sin(phi2) * sin(phi1)))) * R);
              	end
              	return tmp
              end
              
              code[R_, lambda1_, lambda2_, phi1_, phi2_] := Block[{t$95$0 = N[Cos[N[(lambda1 - lambda2), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[phi2, 0.145], 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] + N[(N[Sin[phi2], $MachinePrecision] * N[Sin[phi1], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]]]
              
              \begin{array}{l}
              
              \\
              \begin{array}{l}
              t_0 := \cos \left(\lambda_1 - \lambda_2\right)\\
              \mathbf{if}\;\phi_2 \leq 0.145:\\
              \;\;\;\;\cos^{-1} \left(t\_0 \cdot \cos \phi_1\right) \cdot R\\
              
              \mathbf{else}:\\
              \;\;\;\;\cos^{-1} \left(\mathsf{fma}\left(t\_0, \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right) \cdot R\\
              
              
              \end{array}
              \end{array}
              
              Derivation
              1. Split input into 2 regimes
              2. if phi2 < 0.14499999999999999

                1. Initial program 72.0%

                  \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                2. 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.f6451.1

                    \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                4. Applied rewrites51.1%

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

                if 0.14499999999999999 < phi2

                1. Initial program 78.1%

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

                  \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \color{blue}{\cos \phi_2} \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                3. Step-by-step derivation
                  1. lift-cos.f6447.5

                    \[\leadsto \cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_2 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                4. Applied rewrites47.5%

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

                    \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right), \cos \phi_2, \sin \phi_2 \cdot \color{blue}{\sin \phi_1}\right)\right) \cdot R \]
                  16. lift-*.f6447.5

                    \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right), \cos \phi_2, \color{blue}{\sin \phi_2 \cdot \sin \phi_1}\right)\right) \cdot R \]
                6. Applied rewrites47.5%

                  \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(\cos \left(\lambda_1 - \lambda_2\right), \cos \phi_2, \sin \phi_2 \cdot \sin \phi_1\right)\right)} \cdot R \]
              3. Recombined 2 regimes into one program.
              4. Add Preprocessing

              Alternative 12: 50.3% accurate, 1.9× speedup?

              \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\lambda_1 - \lambda_2\right)\\ \mathbf{if}\;\phi_1 \leq -3.5 \cdot 10^{-5}:\\ \;\;\;\;\left(\frac{\pi}{2} - \sin^{-1} \left(\cos \phi_1 \cdot t\_0\right)\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(t\_0 \cdot \cos \phi_2\right) \cdot R\\ \end{array} \end{array} \]
              (FPCore (R lambda1 lambda2 phi1 phi2)
               :precision binary64
               (let* ((t_0 (cos (- lambda1 lambda2))))
                 (if (<= phi1 -3.5e-5)
                   (* (- (/ PI 2.0) (asin (* (cos phi1) t_0))) 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 <= -3.5e-5) {
              		tmp = ((((double) M_PI) / 2.0) - asin((cos(phi1) * t_0))) * R;
              	} else {
              		tmp = acos((t_0 * cos(phi2))) * R;
              	}
              	return tmp;
              }
              
              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 <= -3.5e-5) {
              		tmp = ((Math.PI / 2.0) - Math.asin((Math.cos(phi1) * t_0))) * 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 <= -3.5e-5:
              		tmp = ((math.pi / 2.0) - math.asin((math.cos(phi1) * t_0))) * 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 <= -3.5e-5)
              		tmp = Float64(Float64(Float64(pi / 2.0) - asin(Float64(cos(phi1) * t_0))) * 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 <= -3.5e-5)
              		tmp = ((pi / 2.0) - asin((cos(phi1) * t_0))) * 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, -3.5e-5], N[(N[(N[(Pi / 2.0), $MachinePrecision] - N[ArcSin[N[(N[Cos[phi1], $MachinePrecision] * t$95$0), $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 -3.5 \cdot 10^{-5}:\\
              \;\;\;\;\left(\frac{\pi}{2} - \sin^{-1} \left(\cos \phi_1 \cdot t\_0\right)\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 < -3.4999999999999997e-5

                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-acos.f64N/A

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

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

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

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

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

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

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

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

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

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

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

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

                    \[\leadsto \color{blue}{\left(\frac{\mathsf{PI}\left(\right)}{2} - \sin^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right)} \cdot R \]
                3. Applied rewrites79.6%

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

                  \[\leadsto \left(\frac{\pi}{2} - \sin^{-1} \color{blue}{\left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)}\right) \cdot R \]
                5. Step-by-step derivation
                  1. lower-*.f64N/A

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

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

                    \[\leadsto \left(\frac{\pi}{2} - \sin^{-1} \left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
                  4. lift--.f6449.6

                    \[\leadsto \left(\frac{\pi}{2} - \sin^{-1} \left(\cos \phi_1 \cdot \cos \left(\lambda_1 - \lambda_2\right)\right)\right) \cdot R \]
                6. Applied rewrites49.6%

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

                if -3.4999999999999997e-5 < phi1

                1. Initial program 71.5%

                  \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                2. Taylor expanded in 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.f6450.5

                    \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot R \]
                4. Applied rewrites50.5%

                  \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right)} \cdot R \]
              3. Recombined 2 regimes into one program.
              4. Add Preprocessing

              Alternative 13: 42.7% accurate, 1.9× speedup?

              \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \left(\cos \phi_1 \cdot \cos \lambda_2\right) \cdot R\\ \mathbf{if}\;\lambda_2 \leq -6:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\lambda_2 \leq 0.016:\\ \;\;\;\;\cos^{-1} \left(\cos \lambda_1 \cdot \cos \phi_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
              (FPCore (R lambda1 lambda2 phi1 phi2)
               :precision binary64
               (let* ((t_0 (* (acos (* (cos phi1) (cos lambda2))) R)))
                 (if (<= lambda2 -6.0)
                   t_0
                   (if (<= lambda2 0.016) (* (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(phi1) * cos(lambda2))) * R;
              	double tmp;
              	if (lambda2 <= -6.0) {
              		tmp = t_0;
              	} else if (lambda2 <= 0.016) {
              		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(phi1) * cos(lambda2))) * r
                  if (lambda2 <= (-6.0d0)) then
                      tmp = t_0
                  else if (lambda2 <= 0.016d0) 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(phi1) * Math.cos(lambda2))) * R;
              	double tmp;
              	if (lambda2 <= -6.0) {
              		tmp = t_0;
              	} else if (lambda2 <= 0.016) {
              		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(phi1) * math.cos(lambda2))) * R
              	tmp = 0
              	if lambda2 <= -6.0:
              		tmp = t_0
              	elif lambda2 <= 0.016:
              		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(phi1) * cos(lambda2))) * R)
              	tmp = 0.0
              	if (lambda2 <= -6.0)
              		tmp = t_0;
              	elseif (lambda2 <= 0.016)
              		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(phi1) * cos(lambda2))) * R;
              	tmp = 0.0;
              	if (lambda2 <= -6.0)
              		tmp = t_0;
              	elseif (lambda2 <= 0.016)
              		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[phi1], $MachinePrecision] * N[Cos[lambda2], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[lambda2, -6.0], t$95$0, If[LessEqual[lambda2, 0.016], 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 \phi_1 \cdot \cos \lambda_2\right) \cdot R\\
              \mathbf{if}\;\lambda_2 \leq -6:\\
              \;\;\;\;t\_0\\
              
              \mathbf{elif}\;\lambda_2 \leq 0.016:\\
              \;\;\;\;\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 < -6 or 0.016 < lambda2

                1. Initial program 59.9%

                  \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                2. Taylor expanded in 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.f6440.0

                    \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                4. Applied rewrites40.0%

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

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

                    \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \cos \lambda_2\right) \cdot R \]
                  4. lift-cos.f6439.9

                    \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \cos \lambda_2\right) \cdot R \]
                7. Applied rewrites39.9%

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

                if -6 < lambda2 < 0.016

                1. Initial program 87.6%

                  \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                2. Taylor expanded in 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.f6446.0

                    \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                4. Applied rewrites46.0%

                  \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                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 rewrites45.6%

                    \[\leadsto \cos^{-1} \left(\cos \lambda_1 \cdot \cos \phi_1\right) \cdot R \]
                7. Recombined 2 regimes into one program.
                8. Add Preprocessing

                Alternative 14: 50.3% accurate, 2.0× speedup?

                \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\lambda_1 - \lambda_2\right)\\ \mathbf{if}\;\phi_2 \leq 0.145:\\ \;\;\;\;\cos^{-1} \left(t\_0 \cdot \cos \phi_1\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \left(t\_0 \cdot \cos \phi_2\right) \cdot R\\ \end{array} \end{array} \]
                (FPCore (R lambda1 lambda2 phi1 phi2)
                 :precision binary64
                 (let* ((t_0 (cos (- lambda1 lambda2))))
                   (if (<= phi2 0.145)
                     (* (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 (phi2 <= 0.145) {
                		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 (phi2 <= 0.145d0) 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 (phi2 <= 0.145) {
                		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 phi2 <= 0.145:
                		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 (phi2 <= 0.145)
                		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 (phi2 <= 0.145)
                		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[phi2, 0.145], 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_2 \leq 0.145:\\
                \;\;\;\;\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 phi2 < 0.14499999999999999

                  1. Initial program 72.0%

                    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  2. 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.f6451.1

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                  4. Applied rewrites51.1%

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

                  if 0.14499999999999999 < phi2

                  1. Initial program 78.1%

                    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  2. Taylor expanded in 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.f6448.0

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right) \cdot R \]
                  4. Applied rewrites48.0%

                    \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_2\right)} \cdot R \]
                3. Recombined 2 regimes into one program.
                4. Add Preprocessing

                Alternative 15: 32.5% accurate, 2.0× speedup?

                \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\phi_1 \leq -0.00041:\\ \;\;\;\;\cos^{-1} \left(\cos \phi_1 \cdot \cos \lambda_2\right) \cdot R\\ \mathbf{else}:\\ \;\;\;\;\cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R\\ \end{array} \end{array} \]
                (FPCore (R lambda1 lambda2 phi1 phi2)
                 :precision binary64
                 (if (<= phi1 -0.00041)
                   (* (acos (* (cos phi1) (cos lambda2))) R)
                   (* (acos (cos (- lambda1 lambda2))) R)))
                double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                	double tmp;
                	if (phi1 <= -0.00041) {
                		tmp = acos((cos(phi1) * cos(lambda2))) * 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 <= (-0.00041d0)) then
                        tmp = acos((cos(phi1) * cos(lambda2))) * 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 <= -0.00041) {
                		tmp = Math.acos((Math.cos(phi1) * Math.cos(lambda2))) * R;
                	} else {
                		tmp = Math.acos(Math.cos((lambda1 - lambda2))) * R;
                	}
                	return tmp;
                }
                
                def code(R, lambda1, lambda2, phi1, phi2):
                	tmp = 0
                	if phi1 <= -0.00041:
                		tmp = math.acos((math.cos(phi1) * math.cos(lambda2))) * R
                	else:
                		tmp = math.acos(math.cos((lambda1 - lambda2))) * R
                	return tmp
                
                function code(R, lambda1, lambda2, phi1, phi2)
                	tmp = 0.0
                	if (phi1 <= -0.00041)
                		tmp = Float64(acos(Float64(cos(phi1) * cos(lambda2))) * 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 <= -0.00041)
                		tmp = acos((cos(phi1) * cos(lambda2))) * R;
                	else
                		tmp = acos(cos((lambda1 - lambda2))) * R;
                	end
                	tmp_2 = tmp;
                end
                
                code[R_, lambda1_, lambda2_, phi1_, phi2_] := If[LessEqual[phi1, -0.00041], N[(N[ArcCos[N[(N[Cos[phi1], $MachinePrecision] * N[Cos[lambda2], $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 -0.00041:\\
                \;\;\;\;\cos^{-1} \left(\cos \phi_1 \cdot \cos \lambda_2\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 < -4.0999999999999999e-4

                  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. 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.f6449.7

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                  4. Applied rewrites49.7%

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

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

                      \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \cos \lambda_2\right) \cdot R \]
                    4. lift-cos.f6441.0

                      \[\leadsto \cos^{-1} \left(\cos \phi_1 \cdot \cos \lambda_2\right) \cdot R \]
                  7. Applied rewrites41.0%

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

                  if -4.0999999999999999e-4 < phi1

                  1. Initial program 71.5%

                    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  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.f6440.7

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                  4. Applied rewrites40.7%

                    \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                  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--.f6429.8

                      \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                  7. Applied rewrites29.8%

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

                Alternative 16: 42.9% accurate, 2.0× 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 73.5%

                  \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                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.f6442.9

                    \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                4. Applied rewrites42.9%

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

                Alternative 17: 25.9% accurate, 2.9× speedup?

                \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos^{-1} \cos \lambda_1 \cdot R\\ \mathbf{if}\;\lambda_1 \leq -2.5 \cdot 10^{+27}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;\lambda_1 \leq 2.3 \cdot 10^{-15}:\\ \;\;\;\;\cos^{-1} \cos \lambda_2 \cdot R\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
                (FPCore (R lambda1 lambda2 phi1 phi2)
                 :precision binary64
                 (let* ((t_0 (* (acos (cos lambda1)) R)))
                   (if (<= lambda1 -2.5e+27)
                     t_0
                     (if (<= lambda1 2.3e-15) (* (acos (cos lambda2)) R) t_0))))
                double code(double R, double lambda1, double lambda2, double phi1, double phi2) {
                	double t_0 = acos(cos(lambda1)) * R;
                	double tmp;
                	if (lambda1 <= -2.5e+27) {
                		tmp = t_0;
                	} else if (lambda1 <= 2.3e-15) {
                		tmp = acos(cos(lambda2)) * 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(lambda1)) * r
                    if (lambda1 <= (-2.5d+27)) then
                        tmp = t_0
                    else if (lambda1 <= 2.3d-15) then
                        tmp = acos(cos(lambda2)) * 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(lambda1)) * R;
                	double tmp;
                	if (lambda1 <= -2.5e+27) {
                		tmp = t_0;
                	} else if (lambda1 <= 2.3e-15) {
                		tmp = Math.acos(Math.cos(lambda2)) * R;
                	} else {
                		tmp = t_0;
                	}
                	return tmp;
                }
                
                def code(R, lambda1, lambda2, phi1, phi2):
                	t_0 = math.acos(math.cos(lambda1)) * R
                	tmp = 0
                	if lambda1 <= -2.5e+27:
                		tmp = t_0
                	elif lambda1 <= 2.3e-15:
                		tmp = math.acos(math.cos(lambda2)) * R
                	else:
                		tmp = t_0
                	return tmp
                
                function code(R, lambda1, lambda2, phi1, phi2)
                	t_0 = Float64(acos(cos(lambda1)) * R)
                	tmp = 0.0
                	if (lambda1 <= -2.5e+27)
                		tmp = t_0;
                	elseif (lambda1 <= 2.3e-15)
                		tmp = Float64(acos(cos(lambda2)) * R);
                	else
                		tmp = t_0;
                	end
                	return tmp
                end
                
                function tmp_2 = code(R, lambda1, lambda2, phi1, phi2)
                	t_0 = acos(cos(lambda1)) * R;
                	tmp = 0.0;
                	if (lambda1 <= -2.5e+27)
                		tmp = t_0;
                	elseif (lambda1 <= 2.3e-15)
                		tmp = acos(cos(lambda2)) * 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[lambda1], $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision]}, If[LessEqual[lambda1, -2.5e+27], t$95$0, If[LessEqual[lambda1, 2.3e-15], N[(N[ArcCos[N[Cos[lambda2], $MachinePrecision]], $MachinePrecision] * R), $MachinePrecision], t$95$0]]]
                
                \begin{array}{l}
                
                \\
                \begin{array}{l}
                t_0 := \cos^{-1} \cos \lambda_1 \cdot R\\
                \mathbf{if}\;\lambda_1 \leq -2.5 \cdot 10^{+27}:\\
                \;\;\;\;t\_0\\
                
                \mathbf{elif}\;\lambda_1 \leq 2.3 \cdot 10^{-15}:\\
                \;\;\;\;\cos^{-1} \cos \lambda_2 \cdot R\\
                
                \mathbf{else}:\\
                \;\;\;\;t\_0\\
                
                
                \end{array}
                \end{array}
                
                Derivation
                1. Split input into 2 regimes
                2. if lambda1 < -2.4999999999999999e27 or 2.2999999999999999e-15 < lambda1

                  1. Initial program 59.1%

                    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  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.f6438.7

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                  4. Applied rewrites38.7%

                    \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                  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--.f6429.3

                      \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                  7. Applied rewrites29.3%

                    \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                  8. Taylor expanded in lambda1 around 0

                    \[\leadsto \cos^{-1} \cos \left(-1 \cdot \lambda_2\right) \cdot R \]
                  9. Step-by-step derivation
                    1. mul-1-negN/A

                      \[\leadsto \cos^{-1} \cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot R \]
                    2. lower-neg.f6412.1

                      \[\leadsto \cos^{-1} \cos \left(-\lambda_2\right) \cdot R \]
                  10. Applied rewrites12.1%

                    \[\leadsto \cos^{-1} \cos \left(-\lambda_2\right) \cdot R \]
                  11. Taylor expanded in lambda1 around inf

                    \[\leadsto \cos^{-1} \cos \lambda_1 \cdot R \]
                  12. Step-by-step derivation
                    1. Applied rewrites29.0%

                      \[\leadsto \cos^{-1} \cos \lambda_1 \cdot R \]

                    if -2.4999999999999999e27 < lambda1 < 2.2999999999999999e-15

                    1. Initial program 86.8%

                      \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                    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.f6446.8

                        \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                    4. Applied rewrites46.8%

                      \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                    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--.f6423.8

                        \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                    7. Applied rewrites23.8%

                      \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                    8. Taylor expanded in lambda1 around 0

                      \[\leadsto \cos^{-1} \cos \left(-1 \cdot \lambda_2\right) \cdot R \]
                    9. Step-by-step derivation
                      1. mul-1-negN/A

                        \[\leadsto \cos^{-1} \cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot R \]
                      2. lower-neg.f6423.0

                        \[\leadsto \cos^{-1} \cos \left(-\lambda_2\right) \cdot R \]
                    10. Applied rewrites23.0%

                      \[\leadsto \cos^{-1} \cos \left(-\lambda_2\right) \cdot R \]
                    11. Taylor expanded in lambda1 around 0

                      \[\leadsto \cos^{-1} \cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot R \]
                    12. Step-by-step derivation
                      1. cos-neg-revN/A

                        \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                      2. lift-cos.f6423.0

                        \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                    13. Applied rewrites23.0%

                      \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                  13. Recombined 2 regimes into one program.
                  14. Add Preprocessing

                  Alternative 18: 26.4% accurate, 3.0× 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 73.5%

                    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  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.f6442.9

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                  4. Applied rewrites42.9%

                    \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                  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--.f6426.4

                      \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                  7. Applied rewrites26.4%

                    \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                  8. Add Preprocessing

                  Alternative 19: 17.8% accurate, 3.0× 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 73.5%

                    \[\cos^{-1} \left(\sin \phi_1 \cdot \sin \phi_2 + \left(\cos \phi_1 \cdot \cos \phi_2\right) \cdot \cos \left(\lambda_1 - \lambda_2\right)\right) \cdot R \]
                  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.f6442.9

                      \[\leadsto \cos^{-1} \left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right) \cdot R \]
                  4. Applied rewrites42.9%

                    \[\leadsto \cos^{-1} \color{blue}{\left(\cos \left(\lambda_1 - \lambda_2\right) \cdot \cos \phi_1\right)} \cdot R \]
                  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--.f6426.4

                      \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                  7. Applied rewrites26.4%

                    \[\leadsto \cos^{-1} \cos \left(\lambda_1 - \lambda_2\right) \cdot R \]
                  8. Taylor expanded in lambda1 around 0

                    \[\leadsto \cos^{-1} \cos \left(-1 \cdot \lambda_2\right) \cdot R \]
                  9. Step-by-step derivation
                    1. mul-1-negN/A

                      \[\leadsto \cos^{-1} \cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot R \]
                    2. lower-neg.f6417.8

                      \[\leadsto \cos^{-1} \cos \left(-\lambda_2\right) \cdot R \]
                  10. Applied rewrites17.8%

                    \[\leadsto \cos^{-1} \cos \left(-\lambda_2\right) \cdot R \]
                  11. Taylor expanded in lambda1 around 0

                    \[\leadsto \cos^{-1} \cos \left(\mathsf{neg}\left(\lambda_2\right)\right) \cdot R \]
                  12. Step-by-step derivation
                    1. cos-neg-revN/A

                      \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                    2. lift-cos.f6417.8

                      \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                  13. Applied rewrites17.8%

                    \[\leadsto \cos^{-1} \cos \lambda_2 \cdot R \]
                  14. Add Preprocessing

                  Reproduce

                  ?
                  herbie shell --seed 2025097 
                  (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))