Migdal et al, Equation (64)

Percentage Accurate: 99.5% → 99.1%
Time: 3.5s
Alternatives: 5
Speedup: N/A×

Specification

?
\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{\cos th}{\sqrt{2}}\\ t\_1 \cdot \left(a1 \cdot a1\right) + t\_1 \cdot \left(a2 \cdot a2\right) \end{array} \end{array} \]
(FPCore (a1 a2 th)
 :precision binary64
 (let* ((t_1 (/ (cos th) (sqrt 2.0))))
   (+ (* t_1 (* a1 a1)) (* t_1 (* a2 a2)))))
double code(double a1, double a2, double th) {
	double t_1 = cos(th) / sqrt(2.0);
	return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
}
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(a1, a2, th)
use fmin_fmax_functions
    real(8), intent (in) :: a1
    real(8), intent (in) :: a2
    real(8), intent (in) :: th
    real(8) :: t_1
    t_1 = cos(th) / sqrt(2.0d0)
    code = (t_1 * (a1 * a1)) + (t_1 * (a2 * a2))
end function
public static double code(double a1, double a2, double th) {
	double t_1 = Math.cos(th) / Math.sqrt(2.0);
	return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
}
def code(a1, a2, th):
	t_1 = math.cos(th) / math.sqrt(2.0)
	return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2))
function code(a1, a2, th)
	t_1 = Float64(cos(th) / sqrt(2.0))
	return Float64(Float64(t_1 * Float64(a1 * a1)) + Float64(t_1 * Float64(a2 * a2)))
end
function tmp = code(a1, a2, th)
	t_1 = cos(th) / sqrt(2.0);
	tmp = (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
end
code[a1_, a2_, th_] := Block[{t$95$1 = N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, N[(N[(t$95$1 * N[(a1 * a1), $MachinePrecision]), $MachinePrecision] + N[(t$95$1 * N[(a2 * a2), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{\cos th}{\sqrt{2}}\\
t\_1 \cdot \left(a1 \cdot a1\right) + t\_1 \cdot \left(a2 \cdot a2\right)
\end{array}
\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 5 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: 99.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{\cos th}{\sqrt{2}}\\ t\_1 \cdot \left(a1 \cdot a1\right) + t\_1 \cdot \left(a2 \cdot a2\right) \end{array} \end{array} \]
(FPCore (a1 a2 th)
 :precision binary64
 (let* ((t_1 (/ (cos th) (sqrt 2.0))))
   (+ (* t_1 (* a1 a1)) (* t_1 (* a2 a2)))))
double code(double a1, double a2, double th) {
	double t_1 = cos(th) / sqrt(2.0);
	return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
}
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(a1, a2, th)
use fmin_fmax_functions
    real(8), intent (in) :: a1
    real(8), intent (in) :: a2
    real(8), intent (in) :: th
    real(8) :: t_1
    t_1 = cos(th) / sqrt(2.0d0)
    code = (t_1 * (a1 * a1)) + (t_1 * (a2 * a2))
end function
public static double code(double a1, double a2, double th) {
	double t_1 = Math.cos(th) / Math.sqrt(2.0);
	return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
}
def code(a1, a2, th):
	t_1 = math.cos(th) / math.sqrt(2.0)
	return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2))
function code(a1, a2, th)
	t_1 = Float64(cos(th) / sqrt(2.0))
	return Float64(Float64(t_1 * Float64(a1 * a1)) + Float64(t_1 * Float64(a2 * a2)))
end
function tmp = code(a1, a2, th)
	t_1 = cos(th) / sqrt(2.0);
	tmp = (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
end
code[a1_, a2_, th_] := Block[{t$95$1 = N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, N[(N[(t$95$1 * N[(a1 * a1), $MachinePrecision]), $MachinePrecision] + N[(t$95$1 * N[(a2 * a2), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{\cos th}{\sqrt{2}}\\
t\_1 \cdot \left(a1 \cdot a1\right) + t\_1 \cdot \left(a2 \cdot a2\right)
\end{array}
\end{array}

Alternative 1: 99.1% accurate, 2.0× speedup?

\[\begin{array}{l} a1_m = \left|a1\right| \\ a2_m = \left|a2\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \frac{\cos th \cdot a2\_m}{\sqrt{2}} \cdot a2\_m \end{array} \]
a1_m = (fabs.f64 a1)
a2_m = (fabs.f64 a2)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
(FPCore (a1_m a2_m th)
 :precision binary64
 (* (/ (* (cos th) a2_m) (sqrt 2.0)) a2_m))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
	return ((cos(th) * a2_m) / sqrt(2.0)) * a2_m;
}
a1_m =     private
a2_m =     private
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
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(a1_m, a2_m, th)
use fmin_fmax_functions
    real(8), intent (in) :: a1_m
    real(8), intent (in) :: a2_m
    real(8), intent (in) :: th
    code = ((cos(th) * a2_m) / sqrt(2.0d0)) * a2_m
end function
a1_m = Math.abs(a1);
a2_m = Math.abs(a2);
assert a1_m < a2_m && a2_m < th;
public static double code(double a1_m, double a2_m, double th) {
	return ((Math.cos(th) * a2_m) / Math.sqrt(2.0)) * a2_m;
}
a1_m = math.fabs(a1)
a2_m = math.fabs(a2)
[a1_m, a2_m, th] = sort([a1_m, a2_m, th])
def code(a1_m, a2_m, th):
	return ((math.cos(th) * a2_m) / math.sqrt(2.0)) * a2_m
a1_m = abs(a1)
a2_m = abs(a2)
a1_m, a2_m, th = sort([a1_m, a2_m, th])
function code(a1_m, a2_m, th)
	return Float64(Float64(Float64(cos(th) * a2_m) / sqrt(2.0)) * a2_m)
end
a1_m = abs(a1);
a2_m = abs(a2);
a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
function tmp = code(a1_m, a2_m, th)
	tmp = ((cos(th) * a2_m) / sqrt(2.0)) * a2_m;
end
a1_m = N[Abs[a1], $MachinePrecision]
a2_m = N[Abs[a2], $MachinePrecision]
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
code[a1$95$m_, a2$95$m_, th_] := N[(N[(N[(N[Cos[th], $MachinePrecision] * a2$95$m), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * a2$95$m), $MachinePrecision]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
\frac{\cos th \cdot a2\_m}{\sqrt{2}} \cdot a2\_m
\end{array}
Derivation
  1. Initial program 99.5%

    \[\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
  2. Taylor expanded in a1 around 0

    \[\leadsto \color{blue}{\frac{{a2}^{2} \cdot \cos th}{\sqrt{2}}} \]
  3. Step-by-step derivation
    1. associate-/l*N/A

      \[\leadsto {a2}^{2} \cdot \color{blue}{\frac{\cos th}{\sqrt{2}}} \]
    2. *-commutativeN/A

      \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \color{blue}{{a2}^{2}} \]
    3. pow2N/A

      \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot \color{blue}{a2}\right) \]
    4. associate-*r*N/A

      \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
    5. lower-*.f64N/A

      \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
    6. associate-*l/N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    7. lower-/.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    8. lower-*.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    9. lift-cos.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    10. lift-sqrt.f6499.1

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
  4. Applied rewrites99.1%

    \[\leadsto \color{blue}{\frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2} \]
  5. Add Preprocessing

Alternative 2: 99.1% accurate, 2.0× speedup?

\[\begin{array}{l} a1_m = \left|a1\right| \\ a2_m = \left|a2\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \left(\cos th \cdot \frac{a2\_m}{\sqrt{2}}\right) \cdot a2\_m \end{array} \]
a1_m = (fabs.f64 a1)
a2_m = (fabs.f64 a2)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
(FPCore (a1_m a2_m th)
 :precision binary64
 (* (* (cos th) (/ a2_m (sqrt 2.0))) a2_m))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
	return (cos(th) * (a2_m / sqrt(2.0))) * a2_m;
}
a1_m =     private
a2_m =     private
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
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(a1_m, a2_m, th)
use fmin_fmax_functions
    real(8), intent (in) :: a1_m
    real(8), intent (in) :: a2_m
    real(8), intent (in) :: th
    code = (cos(th) * (a2_m / sqrt(2.0d0))) * a2_m
end function
a1_m = Math.abs(a1);
a2_m = Math.abs(a2);
assert a1_m < a2_m && a2_m < th;
public static double code(double a1_m, double a2_m, double th) {
	return (Math.cos(th) * (a2_m / Math.sqrt(2.0))) * a2_m;
}
a1_m = math.fabs(a1)
a2_m = math.fabs(a2)
[a1_m, a2_m, th] = sort([a1_m, a2_m, th])
def code(a1_m, a2_m, th):
	return (math.cos(th) * (a2_m / math.sqrt(2.0))) * a2_m
a1_m = abs(a1)
a2_m = abs(a2)
a1_m, a2_m, th = sort([a1_m, a2_m, th])
function code(a1_m, a2_m, th)
	return Float64(Float64(cos(th) * Float64(a2_m / sqrt(2.0))) * a2_m)
end
a1_m = abs(a1);
a2_m = abs(a2);
a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
function tmp = code(a1_m, a2_m, th)
	tmp = (cos(th) * (a2_m / sqrt(2.0))) * a2_m;
end
a1_m = N[Abs[a1], $MachinePrecision]
a2_m = N[Abs[a2], $MachinePrecision]
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
code[a1$95$m_, a2$95$m_, th_] := N[(N[(N[Cos[th], $MachinePrecision] * N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a2$95$m), $MachinePrecision]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
\left(\cos th \cdot \frac{a2\_m}{\sqrt{2}}\right) \cdot a2\_m
\end{array}
Derivation
  1. Initial program 99.5%

    \[\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
  2. Taylor expanded in a1 around 0

    \[\leadsto \color{blue}{\frac{{a2}^{2} \cdot \cos th}{\sqrt{2}}} \]
  3. Step-by-step derivation
    1. associate-/l*N/A

      \[\leadsto {a2}^{2} \cdot \color{blue}{\frac{\cos th}{\sqrt{2}}} \]
    2. *-commutativeN/A

      \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \color{blue}{{a2}^{2}} \]
    3. pow2N/A

      \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot \color{blue}{a2}\right) \]
    4. associate-*r*N/A

      \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
    5. lower-*.f64N/A

      \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
    6. associate-*l/N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    7. lower-/.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    8. lower-*.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    9. lift-cos.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    10. lift-sqrt.f6499.1

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
  4. Applied rewrites99.1%

    \[\leadsto \color{blue}{\frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2} \]
  5. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    2. lift-*.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    3. lift-cos.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    4. lift-sqrt.f64N/A

      \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    5. associate-/l*N/A

      \[\leadsto \left(\cos th \cdot \frac{a2}{\sqrt{2}}\right) \cdot a2 \]
    6. lower-*.f64N/A

      \[\leadsto \left(\cos th \cdot \frac{a2}{\sqrt{2}}\right) \cdot a2 \]
    7. lift-cos.f64N/A

      \[\leadsto \left(\cos th \cdot \frac{a2}{\sqrt{2}}\right) \cdot a2 \]
    8. lower-/.f64N/A

      \[\leadsto \left(\cos th \cdot \frac{a2}{\sqrt{2}}\right) \cdot a2 \]
    9. lift-sqrt.f6499.1

      \[\leadsto \left(\cos th \cdot \frac{a2}{\sqrt{2}}\right) \cdot a2 \]
  6. Applied rewrites99.1%

    \[\leadsto \left(\cos th \cdot \frac{a2}{\sqrt{2}}\right) \cdot a2 \]
  7. Add Preprocessing

Alternative 3: 77.9% accurate, 0.8× speedup?

\[\begin{array}{l} a1_m = \left|a1\right| \\ a2_m = \left|a2\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \begin{array}{l} t_1 := \frac{\cos th}{\sqrt{2}}\\ \mathbf{if}\;t\_1 \cdot \left(a1\_m \cdot a1\_m\right) + t\_1 \cdot \left(a2\_m \cdot a2\_m\right) \leq -1 \cdot 10^{-71}:\\ \;\;\;\;\frac{\left(\left(a2\_m \cdot th\right) \cdot a2\_m\right) \cdot th}{\sqrt{2}} \cdot -0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{a2\_m}{\sqrt{2}} \cdot a2\_m\\ \end{array} \end{array} \]
a1_m = (fabs.f64 a1)
a2_m = (fabs.f64 a2)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
(FPCore (a1_m a2_m th)
 :precision binary64
 (let* ((t_1 (/ (cos th) (sqrt 2.0))))
   (if (<= (+ (* t_1 (* a1_m a1_m)) (* t_1 (* a2_m a2_m))) -1e-71)
     (* (/ (* (* (* a2_m th) a2_m) th) (sqrt 2.0)) -0.5)
     (* (/ a2_m (sqrt 2.0)) a2_m))))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
	double t_1 = cos(th) / sqrt(2.0);
	double tmp;
	if (((t_1 * (a1_m * a1_m)) + (t_1 * (a2_m * a2_m))) <= -1e-71) {
		tmp = ((((a2_m * th) * a2_m) * th) / sqrt(2.0)) * -0.5;
	} else {
		tmp = (a2_m / sqrt(2.0)) * a2_m;
	}
	return tmp;
}
a1_m =     private
a2_m =     private
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
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(a1_m, a2_m, th)
use fmin_fmax_functions
    real(8), intent (in) :: a1_m
    real(8), intent (in) :: a2_m
    real(8), intent (in) :: th
    real(8) :: t_1
    real(8) :: tmp
    t_1 = cos(th) / sqrt(2.0d0)
    if (((t_1 * (a1_m * a1_m)) + (t_1 * (a2_m * a2_m))) <= (-1d-71)) then
        tmp = ((((a2_m * th) * a2_m) * th) / sqrt(2.0d0)) * (-0.5d0)
    else
        tmp = (a2_m / sqrt(2.0d0)) * a2_m
    end if
    code = tmp
end function
a1_m = Math.abs(a1);
a2_m = Math.abs(a2);
assert a1_m < a2_m && a2_m < th;
public static double code(double a1_m, double a2_m, double th) {
	double t_1 = Math.cos(th) / Math.sqrt(2.0);
	double tmp;
	if (((t_1 * (a1_m * a1_m)) + (t_1 * (a2_m * a2_m))) <= -1e-71) {
		tmp = ((((a2_m * th) * a2_m) * th) / Math.sqrt(2.0)) * -0.5;
	} else {
		tmp = (a2_m / Math.sqrt(2.0)) * a2_m;
	}
	return tmp;
}
a1_m = math.fabs(a1)
a2_m = math.fabs(a2)
[a1_m, a2_m, th] = sort([a1_m, a2_m, th])
def code(a1_m, a2_m, th):
	t_1 = math.cos(th) / math.sqrt(2.0)
	tmp = 0
	if ((t_1 * (a1_m * a1_m)) + (t_1 * (a2_m * a2_m))) <= -1e-71:
		tmp = ((((a2_m * th) * a2_m) * th) / math.sqrt(2.0)) * -0.5
	else:
		tmp = (a2_m / math.sqrt(2.0)) * a2_m
	return tmp
a1_m = abs(a1)
a2_m = abs(a2)
a1_m, a2_m, th = sort([a1_m, a2_m, th])
function code(a1_m, a2_m, th)
	t_1 = Float64(cos(th) / sqrt(2.0))
	tmp = 0.0
	if (Float64(Float64(t_1 * Float64(a1_m * a1_m)) + Float64(t_1 * Float64(a2_m * a2_m))) <= -1e-71)
		tmp = Float64(Float64(Float64(Float64(Float64(a2_m * th) * a2_m) * th) / sqrt(2.0)) * -0.5);
	else
		tmp = Float64(Float64(a2_m / sqrt(2.0)) * a2_m);
	end
	return tmp
end
a1_m = abs(a1);
a2_m = abs(a2);
a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
function tmp_2 = code(a1_m, a2_m, th)
	t_1 = cos(th) / sqrt(2.0);
	tmp = 0.0;
	if (((t_1 * (a1_m * a1_m)) + (t_1 * (a2_m * a2_m))) <= -1e-71)
		tmp = ((((a2_m * th) * a2_m) * th) / sqrt(2.0)) * -0.5;
	else
		tmp = (a2_m / sqrt(2.0)) * a2_m;
	end
	tmp_2 = tmp;
end
a1_m = N[Abs[a1], $MachinePrecision]
a2_m = N[Abs[a2], $MachinePrecision]
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
code[a1$95$m_, a2$95$m_, th_] := Block[{t$95$1 = N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[(N[(t$95$1 * N[(a1$95$m * a1$95$m), $MachinePrecision]), $MachinePrecision] + N[(t$95$1 * N[(a2$95$m * a2$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -1e-71], N[(N[(N[(N[(N[(a2$95$m * th), $MachinePrecision] * a2$95$m), $MachinePrecision] * th), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * -0.5), $MachinePrecision], N[(N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * a2$95$m), $MachinePrecision]]]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
\begin{array}{l}
t_1 := \frac{\cos th}{\sqrt{2}}\\
\mathbf{if}\;t\_1 \cdot \left(a1\_m \cdot a1\_m\right) + t\_1 \cdot \left(a2\_m \cdot a2\_m\right) \leq -1 \cdot 10^{-71}:\\
\;\;\;\;\frac{\left(\left(a2\_m \cdot th\right) \cdot a2\_m\right) \cdot th}{\sqrt{2}} \cdot -0.5\\

\mathbf{else}:\\
\;\;\;\;\frac{a2\_m}{\sqrt{2}} \cdot a2\_m\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (+.f64 (*.f64 (/.f64 (cos.f64 th) (sqrt.f64 #s(literal 2 binary64))) (*.f64 a1 a1)) (*.f64 (/.f64 (cos.f64 th) (sqrt.f64 #s(literal 2 binary64))) (*.f64 a2 a2))) < -9.9999999999999992e-72

    1. Initial program 99.6%

      \[\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
    2. Taylor expanded in a1 around 0

      \[\leadsto \color{blue}{\frac{{a2}^{2} \cdot \cos th}{\sqrt{2}}} \]
    3. Step-by-step derivation
      1. associate-/l*N/A

        \[\leadsto {a2}^{2} \cdot \color{blue}{\frac{\cos th}{\sqrt{2}}} \]
      2. *-commutativeN/A

        \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \color{blue}{{a2}^{2}} \]
      3. pow2N/A

        \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot \color{blue}{a2}\right) \]
      4. associate-*r*N/A

        \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
      5. lower-*.f64N/A

        \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
      6. associate-*l/N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      7. lower-/.f64N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      8. lower-*.f64N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      9. lift-cos.f64N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      10. lift-sqrt.f6499.1

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    4. Applied rewrites99.1%

      \[\leadsto \color{blue}{\frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2} \]
    5. Taylor expanded in th around 0

      \[\leadsto \frac{-1}{2} \cdot \frac{{a2}^{2} \cdot {th}^{2}}{\sqrt{2}} + \color{blue}{\frac{{a2}^{2}}{\sqrt{2}}} \]
    6. Step-by-step derivation
      1. associate-*r/N/A

        \[\leadsto \frac{\frac{-1}{2} \cdot \left({a2}^{2} \cdot {th}^{2}\right)}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{\color{blue}{2}}} \]
      2. div-add-revN/A

        \[\leadsto \frac{\frac{-1}{2} \cdot \left({a2}^{2} \cdot {th}^{2}\right) + {a2}^{2}}{\sqrt{2}} \]
      3. lower-/.f64N/A

        \[\leadsto \frac{\frac{-1}{2} \cdot \left({a2}^{2} \cdot {th}^{2}\right) + {a2}^{2}}{\sqrt{2}} \]
      4. lower-fma.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{-1}{2}, {a2}^{2} \cdot {th}^{2}, {a2}^{2}\right)}{\sqrt{2}} \]
      5. pow-prod-downN/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{-1}{2}, {\left(a2 \cdot th\right)}^{2}, {a2}^{2}\right)}{\sqrt{2}} \]
      6. unpow2N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{-1}{2}, \left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right), {a2}^{2}\right)}{\sqrt{2}} \]
      7. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{-1}{2}, \left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right), {a2}^{2}\right)}{\sqrt{2}} \]
      8. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{-1}{2}, \left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right), {a2}^{2}\right)}{\sqrt{2}} \]
      9. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{-1}{2}, \left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right), {a2}^{2}\right)}{\sqrt{2}} \]
      10. pow2N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{-1}{2}, \left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right), a2 \cdot a2\right)}{\sqrt{2}} \]
      11. lift-*.f64N/A

        \[\leadsto \frac{\mathsf{fma}\left(\frac{-1}{2}, \left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right), a2 \cdot a2\right)}{\sqrt{2}} \]
      12. lift-sqrt.f642.5

        \[\leadsto \frac{\mathsf{fma}\left(-0.5, \left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right), a2 \cdot a2\right)}{\sqrt{2}} \]
    7. Applied rewrites2.5%

      \[\leadsto \frac{\mathsf{fma}\left(-0.5, \left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right), a2 \cdot a2\right)}{\color{blue}{\sqrt{2}}} \]
    8. Taylor expanded in th around inf

      \[\leadsto \frac{-1}{2} \cdot \frac{{a2}^{2} \cdot {th}^{2}}{\color{blue}{\sqrt{2}}} \]
    9. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{{a2}^{2} \cdot {th}^{2}}{\sqrt{2}} \cdot \frac{-1}{2} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{{a2}^{2} \cdot {th}^{2}}{\sqrt{2}} \cdot \frac{-1}{2} \]
      3. pow-prod-downN/A

        \[\leadsto \frac{{\left(a2 \cdot th\right)}^{2}}{\sqrt{2}} \cdot \frac{-1}{2} \]
      4. pow2N/A

        \[\leadsto \frac{\left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right)}{\sqrt{2}} \cdot \frac{-1}{2} \]
      5. lift-*.f64N/A

        \[\leadsto \frac{\left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right)}{\sqrt{2}} \cdot \frac{-1}{2} \]
      6. lift-*.f64N/A

        \[\leadsto \frac{\left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right)}{\sqrt{2}} \cdot \frac{-1}{2} \]
      7. lift-*.f64N/A

        \[\leadsto \frac{\left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right)}{\sqrt{2}} \cdot \frac{-1}{2} \]
      8. lower-/.f64N/A

        \[\leadsto \frac{\left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right)}{\sqrt{2}} \cdot \frac{-1}{2} \]
      9. lift-*.f64N/A

        \[\leadsto \frac{\left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right)}{\sqrt{2}} \cdot \frac{-1}{2} \]
      10. lift-*.f64N/A

        \[\leadsto \frac{\left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right)}{\sqrt{2}} \cdot \frac{-1}{2} \]
      11. lift-*.f64N/A

        \[\leadsto \frac{\left(a2 \cdot th\right) \cdot \left(a2 \cdot th\right)}{\sqrt{2}} \cdot \frac{-1}{2} \]
      12. associate-*r*N/A

        \[\leadsto \frac{\left(\left(a2 \cdot th\right) \cdot a2\right) \cdot th}{\sqrt{2}} \cdot \frac{-1}{2} \]
      13. lower-*.f64N/A

        \[\leadsto \frac{\left(\left(a2 \cdot th\right) \cdot a2\right) \cdot th}{\sqrt{2}} \cdot \frac{-1}{2} \]
      14. lower-*.f64N/A

        \[\leadsto \frac{\left(\left(a2 \cdot th\right) \cdot a2\right) \cdot th}{\sqrt{2}} \cdot \frac{-1}{2} \]
      15. lift-*.f64N/A

        \[\leadsto \frac{\left(\left(a2 \cdot th\right) \cdot a2\right) \cdot th}{\sqrt{2}} \cdot \frac{-1}{2} \]
      16. lift-sqrt.f6458.8

        \[\leadsto \frac{\left(\left(a2 \cdot th\right) \cdot a2\right) \cdot th}{\sqrt{2}} \cdot -0.5 \]
    10. Applied rewrites58.8%

      \[\leadsto \frac{\left(\left(a2 \cdot th\right) \cdot a2\right) \cdot th}{\sqrt{2}} \cdot -0.5 \]

    if -9.9999999999999992e-72 < (+.f64 (*.f64 (/.f64 (cos.f64 th) (sqrt.f64 #s(literal 2 binary64))) (*.f64 a1 a1)) (*.f64 (/.f64 (cos.f64 th) (sqrt.f64 #s(literal 2 binary64))) (*.f64 a2 a2)))

    1. Initial program 99.5%

      \[\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
    2. Taylor expanded in a1 around 0

      \[\leadsto \color{blue}{\frac{{a2}^{2} \cdot \cos th}{\sqrt{2}}} \]
    3. Step-by-step derivation
      1. associate-/l*N/A

        \[\leadsto {a2}^{2} \cdot \color{blue}{\frac{\cos th}{\sqrt{2}}} \]
      2. *-commutativeN/A

        \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \color{blue}{{a2}^{2}} \]
      3. pow2N/A

        \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot \color{blue}{a2}\right) \]
      4. associate-*r*N/A

        \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
      5. lower-*.f64N/A

        \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
      6. associate-*l/N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      7. lower-/.f64N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      8. lower-*.f64N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      9. lift-cos.f64N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      10. lift-sqrt.f6499.1

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    4. Applied rewrites99.1%

      \[\leadsto \color{blue}{\frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2} \]
    5. Taylor expanded in th around 0

      \[\leadsto \frac{a2}{\sqrt{2}} \cdot a2 \]
    6. Step-by-step derivation
      1. Applied rewrites82.6%

        \[\leadsto \frac{a2}{\sqrt{2}} \cdot a2 \]
    7. Recombined 2 regimes into one program.
    8. Add Preprocessing

    Alternative 4: 66.3% accurate, 9.9× speedup?

    \[\begin{array}{l} a1_m = \left|a1\right| \\ a2_m = \left|a2\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \frac{a2\_m}{\sqrt{2}} \cdot a2\_m \end{array} \]
    a1_m = (fabs.f64 a1)
    a2_m = (fabs.f64 a2)
    NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
    (FPCore (a1_m a2_m th) :precision binary64 (* (/ a2_m (sqrt 2.0)) a2_m))
    a1_m = fabs(a1);
    a2_m = fabs(a2);
    assert(a1_m < a2_m && a2_m < th);
    double code(double a1_m, double a2_m, double th) {
    	return (a2_m / sqrt(2.0)) * a2_m;
    }
    
    a1_m =     private
    a2_m =     private
    NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
    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(a1_m, a2_m, th)
    use fmin_fmax_functions
        real(8), intent (in) :: a1_m
        real(8), intent (in) :: a2_m
        real(8), intent (in) :: th
        code = (a2_m / sqrt(2.0d0)) * a2_m
    end function
    
    a1_m = Math.abs(a1);
    a2_m = Math.abs(a2);
    assert a1_m < a2_m && a2_m < th;
    public static double code(double a1_m, double a2_m, double th) {
    	return (a2_m / Math.sqrt(2.0)) * a2_m;
    }
    
    a1_m = math.fabs(a1)
    a2_m = math.fabs(a2)
    [a1_m, a2_m, th] = sort([a1_m, a2_m, th])
    def code(a1_m, a2_m, th):
    	return (a2_m / math.sqrt(2.0)) * a2_m
    
    a1_m = abs(a1)
    a2_m = abs(a2)
    a1_m, a2_m, th = sort([a1_m, a2_m, th])
    function code(a1_m, a2_m, th)
    	return Float64(Float64(a2_m / sqrt(2.0)) * a2_m)
    end
    
    a1_m = abs(a1);
    a2_m = abs(a2);
    a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
    function tmp = code(a1_m, a2_m, th)
    	tmp = (a2_m / sqrt(2.0)) * a2_m;
    end
    
    a1_m = N[Abs[a1], $MachinePrecision]
    a2_m = N[Abs[a2], $MachinePrecision]
    NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
    code[a1$95$m_, a2$95$m_, th_] := N[(N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * a2$95$m), $MachinePrecision]
    
    \begin{array}{l}
    a1_m = \left|a1\right|
    \\
    a2_m = \left|a2\right|
    \\
    [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
    \\
    \frac{a2\_m}{\sqrt{2}} \cdot a2\_m
    \end{array}
    
    Derivation
    1. Initial program 99.5%

      \[\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
    2. Taylor expanded in a1 around 0

      \[\leadsto \color{blue}{\frac{{a2}^{2} \cdot \cos th}{\sqrt{2}}} \]
    3. Step-by-step derivation
      1. associate-/l*N/A

        \[\leadsto {a2}^{2} \cdot \color{blue}{\frac{\cos th}{\sqrt{2}}} \]
      2. *-commutativeN/A

        \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \color{blue}{{a2}^{2}} \]
      3. pow2N/A

        \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot \color{blue}{a2}\right) \]
      4. associate-*r*N/A

        \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
      5. lower-*.f64N/A

        \[\leadsto \left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot \color{blue}{a2} \]
      6. associate-*l/N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      7. lower-/.f64N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      8. lower-*.f64N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      9. lift-cos.f64N/A

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
      10. lift-sqrt.f6499.1

        \[\leadsto \frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2 \]
    4. Applied rewrites99.1%

      \[\leadsto \color{blue}{\frac{\cos th \cdot a2}{\sqrt{2}} \cdot a2} \]
    5. Taylor expanded in th around 0

      \[\leadsto \frac{a2}{\sqrt{2}} \cdot a2 \]
    6. Step-by-step derivation
      1. Applied rewrites66.3%

        \[\leadsto \frac{a2}{\sqrt{2}} \cdot a2 \]
      2. Add Preprocessing

      Alternative 5: 13.6% accurate, 9.9× speedup?

      \[\begin{array}{l} a1_m = \left|a1\right| \\ a2_m = \left|a2\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \frac{a1\_m}{\sqrt{2}} \cdot a1\_m \end{array} \]
      a1_m = (fabs.f64 a1)
      a2_m = (fabs.f64 a2)
      NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
      (FPCore (a1_m a2_m th) :precision binary64 (* (/ a1_m (sqrt 2.0)) a1_m))
      a1_m = fabs(a1);
      a2_m = fabs(a2);
      assert(a1_m < a2_m && a2_m < th);
      double code(double a1_m, double a2_m, double th) {
      	return (a1_m / sqrt(2.0)) * a1_m;
      }
      
      a1_m =     private
      a2_m =     private
      NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
      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(a1_m, a2_m, th)
      use fmin_fmax_functions
          real(8), intent (in) :: a1_m
          real(8), intent (in) :: a2_m
          real(8), intent (in) :: th
          code = (a1_m / sqrt(2.0d0)) * a1_m
      end function
      
      a1_m = Math.abs(a1);
      a2_m = Math.abs(a2);
      assert a1_m < a2_m && a2_m < th;
      public static double code(double a1_m, double a2_m, double th) {
      	return (a1_m / Math.sqrt(2.0)) * a1_m;
      }
      
      a1_m = math.fabs(a1)
      a2_m = math.fabs(a2)
      [a1_m, a2_m, th] = sort([a1_m, a2_m, th])
      def code(a1_m, a2_m, th):
      	return (a1_m / math.sqrt(2.0)) * a1_m
      
      a1_m = abs(a1)
      a2_m = abs(a2)
      a1_m, a2_m, th = sort([a1_m, a2_m, th])
      function code(a1_m, a2_m, th)
      	return Float64(Float64(a1_m / sqrt(2.0)) * a1_m)
      end
      
      a1_m = abs(a1);
      a2_m = abs(a2);
      a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
      function tmp = code(a1_m, a2_m, th)
      	tmp = (a1_m / sqrt(2.0)) * a1_m;
      end
      
      a1_m = N[Abs[a1], $MachinePrecision]
      a2_m = N[Abs[a2], $MachinePrecision]
      NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
      code[a1$95$m_, a2$95$m_, th_] := N[(N[(a1$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * a1$95$m), $MachinePrecision]
      
      \begin{array}{l}
      a1_m = \left|a1\right|
      \\
      a2_m = \left|a2\right|
      \\
      [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
      \\
      \frac{a1\_m}{\sqrt{2}} \cdot a1\_m
      \end{array}
      
      Derivation
      1. Initial program 99.5%

        \[\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
      2. Taylor expanded in th around 0

        \[\leadsto \color{blue}{\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}} \]
      3. Step-by-step derivation
        1. +-commutativeN/A

          \[\leadsto \frac{{a2}^{2}}{\sqrt{2}} + \color{blue}{\frac{{a1}^{2}}{\sqrt{2}}} \]
        2. div-add-revN/A

          \[\leadsto \frac{{a2}^{2} + {a1}^{2}}{\color{blue}{\sqrt{2}}} \]
        3. lower-/.f64N/A

          \[\leadsto \frac{{a2}^{2} + {a1}^{2}}{\color{blue}{\sqrt{2}}} \]
        4. pow2N/A

          \[\leadsto \frac{a2 \cdot a2 + {a1}^{2}}{\sqrt{2}} \]
        5. lower-fma.f64N/A

          \[\leadsto \frac{\mathsf{fma}\left(a2, a2, {a1}^{2}\right)}{\sqrt{\color{blue}{2}}} \]
        6. pow2N/A

          \[\leadsto \frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}} \]
        7. lift-*.f64N/A

          \[\leadsto \frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}} \]
        8. lift-sqrt.f6466.5

          \[\leadsto \frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}} \]
      4. Applied rewrites66.5%

        \[\leadsto \color{blue}{\frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}}} \]
      5. Taylor expanded in a1 around inf

        \[\leadsto \frac{{a1}^{2}}{\color{blue}{\sqrt{2}}} \]
      6. Step-by-step derivation
        1. pow2N/A

          \[\leadsto \frac{a1 \cdot a1}{\sqrt{2}} \]
        2. associate-*r/N/A

          \[\leadsto a1 \cdot \frac{a1}{\color{blue}{\sqrt{2}}} \]
        3. *-commutativeN/A

          \[\leadsto \frac{a1}{\sqrt{2}} \cdot a1 \]
        4. lower-*.f64N/A

          \[\leadsto \frac{a1}{\sqrt{2}} \cdot a1 \]
        5. lift-sqrt.f64N/A

          \[\leadsto \frac{a1}{\sqrt{2}} \cdot a1 \]
        6. lift-/.f6413.6

          \[\leadsto \frac{a1}{\sqrt{2}} \cdot a1 \]
      7. Applied rewrites13.6%

        \[\leadsto \frac{a1}{\sqrt{2}} \cdot \color{blue}{a1} \]
      8. Add Preprocessing

      Reproduce

      ?
      herbie shell --seed 2025121 
      (FPCore (a1 a2 th)
        :name "Migdal et al, Equation (64)"
        :precision binary64
        (+ (* (/ (cos th) (sqrt 2.0)) (* a1 a1)) (* (/ (cos th) (sqrt 2.0)) (* a2 a2))))