Migdal et al, Equation (64)

Percentage Accurate: 99.6% → 99.6%
Time: 7.7s
Alternatives: 10
Speedup: 1.9×

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}

Sampling outcomes in binary64 precision:

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 10 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: 99.6% 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: 99.6% accurate, 1.0× speedup?

\[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \mathsf{fma}\left(\frac{\cos th \cdot a2\_m}{\sqrt{2}}, a2\_m, \left(a1\_m \cdot a1\_m\right) \cdot \frac{\cos th}{\sqrt{2}}\right) \end{array} \]
a2_m = (fabs.f64 a2)
a1_m = (fabs.f64 a1)
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
 (fma
  (/ (* (cos th) a2_m) (sqrt 2.0))
  a2_m
  (* (* a1_m a1_m) (/ (cos th) (sqrt 2.0)))))
a2_m = fabs(a2);
a1_m = fabs(a1);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
	return fma(((cos(th) * a2_m) / sqrt(2.0)), a2_m, ((a1_m * a1_m) * (cos(th) / sqrt(2.0))));
}
a2_m = abs(a2)
a1_m = abs(a1)
a1_m, a2_m, th = sort([a1_m, a2_m, th])
function code(a1_m, a2_m, th)
	return fma(Float64(Float64(cos(th) * a2_m) / sqrt(2.0)), a2_m, Float64(Float64(a1_m * a1_m) * Float64(cos(th) / sqrt(2.0))))
end
a2_m = N[Abs[a2], $MachinePrecision]
a1_m = N[Abs[a1], $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 + N[(N[(a1$95$m * a1$95$m), $MachinePrecision] * N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a2_m = \left|a2\right|
\\
a1_m = \left|a1\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
\mathsf{fma}\left(\frac{\cos th \cdot a2\_m}{\sqrt{2}}, a2\_m, \left(a1\_m \cdot a1\_m\right) \cdot \frac{\cos th}{\sqrt{2}}\right)
\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. Add Preprocessing
  3. Step-by-step derivation
    1. lift-+.f64N/A

      \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right)} \]
    2. +-commutativeN/A

      \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right)} \]
    3. lift-*.f64N/A

      \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right)} + \frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) \]
    4. lift-*.f64N/A

      \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \color{blue}{\left(a2 \cdot a2\right)} + \frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) \]
    5. associate-*r*N/A

      \[\leadsto \color{blue}{\left(\frac{\cos th}{\sqrt{2}} \cdot a2\right) \cdot a2} + \frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) \]
    6. lower-fma.f64N/A

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

      \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\cos th}{\sqrt{2}}} \cdot a2, a2, \frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right)\right) \]
    8. associate-*l/N/A

      \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\cos th \cdot a2}{\sqrt{2}}}, a2, \frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right)\right) \]
    9. lower-/.f64N/A

      \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\cos th \cdot a2}{\sqrt{2}}}, a2, \frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right)\right) \]
    10. lower-*.f6499.5

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

      \[\leadsto \mathsf{fma}\left(\frac{\cos th \cdot a2}{\sqrt{2}}, a2, \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right)}\right) \]
    12. *-commutativeN/A

      \[\leadsto \mathsf{fma}\left(\frac{\cos th \cdot a2}{\sqrt{2}}, a2, \color{blue}{\left(a1 \cdot a1\right) \cdot \frac{\cos th}{\sqrt{2}}}\right) \]
    13. lower-*.f6499.5

      \[\leadsto \mathsf{fma}\left(\frac{\cos th \cdot a2}{\sqrt{2}}, a2, \color{blue}{\left(a1 \cdot a1\right) \cdot \frac{\cos th}{\sqrt{2}}}\right) \]
  4. Applied rewrites99.5%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\cos th \cdot a2}{\sqrt{2}}, a2, \left(a1 \cdot a1\right) \cdot \frac{\cos th}{\sqrt{2}}\right)} \]
  5. Add Preprocessing

Alternative 2: 78.9% accurate, 0.8× speedup?

\[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \begin{array}{l} t_1 := \frac{\cos th}{\sqrt{2}}\\ \mathbf{if}\;t\_1 \cdot \left(a1\_m \cdot a1\_m\right) + t\_1 \cdot \left(a2\_m \cdot a2\_m\right) \leq -2 \cdot 10^{-136}:\\ \;\;\;\;\mathsf{fma}\left(-0.5 \cdot \left(th \cdot th\right), a2\_m, a2\_m\right) \cdot \frac{a2\_m}{\sqrt{2}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right)}{\sqrt{2}}\\ \end{array} \end{array} \]
a2_m = (fabs.f64 a2)
a1_m = (fabs.f64 a1)
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))) -2e-136)
     (* (fma (* -0.5 (* th th)) a2_m a2_m) (/ a2_m (sqrt 2.0)))
     (/ (fma a2_m a2_m (* a1_m a1_m)) (sqrt 2.0)))))
a2_m = fabs(a2);
a1_m = fabs(a1);
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))) <= -2e-136) {
		tmp = fma((-0.5 * (th * th)), a2_m, a2_m) * (a2_m / sqrt(2.0));
	} else {
		tmp = fma(a2_m, a2_m, (a1_m * a1_m)) / sqrt(2.0);
	}
	return tmp;
}
a2_m = abs(a2)
a1_m = abs(a1)
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))) <= -2e-136)
		tmp = Float64(fma(Float64(-0.5 * Float64(th * th)), a2_m, a2_m) * Float64(a2_m / sqrt(2.0)));
	else
		tmp = Float64(fma(a2_m, a2_m, Float64(a1_m * a1_m)) / sqrt(2.0));
	end
	return tmp
end
a2_m = N[Abs[a2], $MachinePrecision]
a1_m = N[Abs[a1], $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], -2e-136], N[(N[(N[(-0.5 * N[(th * th), $MachinePrecision]), $MachinePrecision] * a2$95$m + a2$95$m), $MachinePrecision] * N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(a2$95$m * a2$95$m + N[(a1$95$m * a1$95$m), $MachinePrecision]), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
a2_m = \left|a2\right|
\\
a1_m = \left|a1\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 -2 \cdot 10^{-136}:\\
\;\;\;\;\mathsf{fma}\left(-0.5 \cdot \left(th \cdot th\right), a2\_m, a2\_m\right) \cdot \frac{a2\_m}{\sqrt{2}}\\

\mathbf{else}:\\
\;\;\;\;\frac{\mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right)}{\sqrt{2}}\\


\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))) < -2e-136

    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. Add Preprocessing
    3. Taylor expanded in a1 around 0

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

        \[\leadsto \frac{\color{blue}{\cos th \cdot {a2}^{2}}}{\sqrt{2}} \]
      2. unpow2N/A

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

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

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

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

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

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

        \[\leadsto \left(\cos th \cdot a2\right) \cdot \color{blue}{\frac{a2}{\sqrt{2}}} \]
      9. lower-sqrt.f6448.3

        \[\leadsto \left(\cos th \cdot a2\right) \cdot \frac{a2}{\color{blue}{\sqrt{2}}} \]
    5. Applied rewrites48.3%

      \[\leadsto \color{blue}{\left(\cos th \cdot a2\right) \cdot \frac{a2}{\sqrt{2}}} \]
    6. Taylor expanded in th around 0

      \[\leadsto \left(a2 + \frac{-1}{2} \cdot \left(a2 \cdot {th}^{2}\right)\right) \cdot \frac{\color{blue}{a2}}{\sqrt{2}} \]
    7. Step-by-step derivation
      1. Applied rewrites49.6%

        \[\leadsto \mathsf{fma}\left(-0.5 \cdot \left(th \cdot th\right), a2, a2\right) \cdot \frac{\color{blue}{a2}}{\sqrt{2}} \]

      if -2e-136 < (+.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. Add Preprocessing
      3. Taylor expanded in th around 0

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

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

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

          \[\leadsto \frac{\color{blue}{{a2}^{2} + {a1}^{2}}}{\sqrt{2}} \]
        4. unpow2N/A

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

          \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(a2, a2, {a1}^{2}\right)}}{\sqrt{2}} \]
        6. unpow2N/A

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

          \[\leadsto \frac{\mathsf{fma}\left(a2, a2, \color{blue}{a1 \cdot a1}\right)}{\sqrt{2}} \]
        8. lower-sqrt.f6485.7

          \[\leadsto \frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\color{blue}{\sqrt{2}}} \]
      5. Applied rewrites85.7%

        \[\leadsto \color{blue}{\frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}}} \]
    8. Recombined 2 regimes into one program.
    9. Add Preprocessing

    Alternative 3: 73.1% accurate, 0.8× speedup?

    \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \begin{array}{l} t_1 := \frac{\cos th}{\sqrt{2}}\\ \mathbf{if}\;t\_1 \cdot \left(a1\_m \cdot a1\_m\right) + t\_1 \cdot \left(a2\_m \cdot a2\_m\right) \leq -2 \cdot 10^{-136}:\\ \;\;\;\;\frac{\mathsf{fma}\left(th \cdot th, -0.5, 1\right)}{\sqrt{2}} \cdot \left(a1\_m \cdot a1\_m\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{\mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right)}{\sqrt{2}}\\ \end{array} \end{array} \]
    a2_m = (fabs.f64 a2)
    a1_m = (fabs.f64 a1)
    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))) -2e-136)
         (* (/ (fma (* th th) -0.5 1.0) (sqrt 2.0)) (* a1_m a1_m))
         (/ (fma a2_m a2_m (* a1_m a1_m)) (sqrt 2.0)))))
    a2_m = fabs(a2);
    a1_m = fabs(a1);
    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))) <= -2e-136) {
    		tmp = (fma((th * th), -0.5, 1.0) / sqrt(2.0)) * (a1_m * a1_m);
    	} else {
    		tmp = fma(a2_m, a2_m, (a1_m * a1_m)) / sqrt(2.0);
    	}
    	return tmp;
    }
    
    a2_m = abs(a2)
    a1_m = abs(a1)
    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))) <= -2e-136)
    		tmp = Float64(Float64(fma(Float64(th * th), -0.5, 1.0) / sqrt(2.0)) * Float64(a1_m * a1_m));
    	else
    		tmp = Float64(fma(a2_m, a2_m, Float64(a1_m * a1_m)) / sqrt(2.0));
    	end
    	return tmp
    end
    
    a2_m = N[Abs[a2], $MachinePrecision]
    a1_m = N[Abs[a1], $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], -2e-136], N[(N[(N[(N[(th * th), $MachinePrecision] * -0.5 + 1.0), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * N[(a1$95$m * a1$95$m), $MachinePrecision]), $MachinePrecision], N[(N[(a2$95$m * a2$95$m + N[(a1$95$m * a1$95$m), $MachinePrecision]), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]]]
    
    \begin{array}{l}
    a2_m = \left|a2\right|
    \\
    a1_m = \left|a1\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 -2 \cdot 10^{-136}:\\
    \;\;\;\;\frac{\mathsf{fma}\left(th \cdot th, -0.5, 1\right)}{\sqrt{2}} \cdot \left(a1\_m \cdot a1\_m\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\frac{\mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right)}{\sqrt{2}}\\
    
    
    \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))) < -2e-136

      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. Add Preprocessing
      3. Taylor expanded in th around 0

        \[\leadsto \color{blue}{{th}^{2} \cdot \left(\frac{-1}{2} \cdot \frac{{a1}^{2}}{\sqrt{2}} + \frac{-1}{2} \cdot \frac{{a2}^{2}}{\sqrt{2}}\right) + \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right)} \]
      4. Step-by-step derivation
        1. distribute-lft-outN/A

          \[\leadsto {th}^{2} \cdot \color{blue}{\left(\frac{-1}{2} \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right)\right)} + \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right) \]
        2. associate-*r*N/A

          \[\leadsto \color{blue}{\left({th}^{2} \cdot \frac{-1}{2}\right) \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right)} + \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right) \]
        3. *-commutativeN/A

          \[\leadsto \color{blue}{\left(\frac{-1}{2} \cdot {th}^{2}\right)} \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right) + \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right) \]
        4. distribute-lft1-inN/A

          \[\leadsto \color{blue}{\left(\frac{-1}{2} \cdot {th}^{2} + 1\right) \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right)} \]
        5. +-commutativeN/A

          \[\leadsto \color{blue}{\left(1 + \frac{-1}{2} \cdot {th}^{2}\right)} \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right) \]
        6. lower-*.f64N/A

          \[\leadsto \color{blue}{\left(1 + \frac{-1}{2} \cdot {th}^{2}\right) \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right)} \]
        7. +-commutativeN/A

          \[\leadsto \color{blue}{\left(\frac{-1}{2} \cdot {th}^{2} + 1\right)} \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right) \]
        8. lower-fma.f64N/A

          \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{-1}{2}, {th}^{2}, 1\right)} \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right) \]
        9. unpow2N/A

          \[\leadsto \mathsf{fma}\left(\frac{-1}{2}, \color{blue}{th \cdot th}, 1\right) \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right) \]
        10. lower-*.f64N/A

          \[\leadsto \mathsf{fma}\left(\frac{-1}{2}, \color{blue}{th \cdot th}, 1\right) \cdot \left(\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}\right) \]
        11. div-add-revN/A

          \[\leadsto \mathsf{fma}\left(\frac{-1}{2}, th \cdot th, 1\right) \cdot \color{blue}{\frac{{a1}^{2} + {a2}^{2}}{\sqrt{2}}} \]
        12. lower-/.f64N/A

          \[\leadsto \mathsf{fma}\left(\frac{-1}{2}, th \cdot th, 1\right) \cdot \color{blue}{\frac{{a1}^{2} + {a2}^{2}}{\sqrt{2}}} \]
      5. Applied rewrites55.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(-0.5, th \cdot th, 1\right) \cdot \frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}}} \]
      6. Taylor expanded in a1 around inf

        \[\leadsto \frac{{a1}^{2} \cdot \left(1 + \frac{-1}{2} \cdot {th}^{2}\right)}{\color{blue}{\sqrt{2}}} \]
      7. Step-by-step derivation
        1. Applied rewrites44.9%

          \[\leadsto \frac{\mathsf{fma}\left(th \cdot th, -0.5, 1\right)}{\sqrt{2}} \cdot \color{blue}{\left(a1 \cdot a1\right)} \]

        if -2e-136 < (+.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. Add Preprocessing
        3. Taylor expanded in th around 0

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

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

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

            \[\leadsto \frac{\color{blue}{{a2}^{2} + {a1}^{2}}}{\sqrt{2}} \]
          4. unpow2N/A

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

            \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(a2, a2, {a1}^{2}\right)}}{\sqrt{2}} \]
          6. unpow2N/A

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

            \[\leadsto \frac{\mathsf{fma}\left(a2, a2, \color{blue}{a1 \cdot a1}\right)}{\sqrt{2}} \]
          8. lower-sqrt.f6485.7

            \[\leadsto \frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\color{blue}{\sqrt{2}}} \]
        5. Applied rewrites85.7%

          \[\leadsto \color{blue}{\frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}}} \]
      8. Recombined 2 regimes into one program.
      9. Add Preprocessing

      Alternative 4: 99.6% accurate, 1.9× speedup?

      \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \frac{\cos th \cdot \mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right)}{\sqrt{2}} \end{array} \]
      a2_m = (fabs.f64 a2)
      a1_m = (fabs.f64 a1)
      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) (fma a2_m a2_m (* a1_m a1_m))) (sqrt 2.0)))
      a2_m = fabs(a2);
      a1_m = fabs(a1);
      assert(a1_m < a2_m && a2_m < th);
      double code(double a1_m, double a2_m, double th) {
      	return (cos(th) * fma(a2_m, a2_m, (a1_m * a1_m))) / sqrt(2.0);
      }
      
      a2_m = abs(a2)
      a1_m = abs(a1)
      a1_m, a2_m, th = sort([a1_m, a2_m, th])
      function code(a1_m, a2_m, th)
      	return Float64(Float64(cos(th) * fma(a2_m, a2_m, Float64(a1_m * a1_m))) / sqrt(2.0))
      end
      
      a2_m = N[Abs[a2], $MachinePrecision]
      a1_m = N[Abs[a1], $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 * a2$95$m + N[(a1$95$m * a1$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]
      
      \begin{array}{l}
      a2_m = \left|a2\right|
      \\
      a1_m = \left|a1\right|
      \\
      [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
      \\
      \frac{\cos th \cdot \mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right)}{\sqrt{2}}
      \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. Add Preprocessing
      3. Step-by-step derivation
        1. lift-+.f64N/A

          \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right)} \]
        2. lift-*.f64N/A

          \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right)} + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
        3. lift-*.f64N/A

          \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right)} \]
        4. distribute-lft-outN/A

          \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)} \]
        5. lift-/.f64N/A

          \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}}} \cdot \left(a1 \cdot a1 + a2 \cdot a2\right) \]
        6. associate-*l/N/A

          \[\leadsto \color{blue}{\frac{\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)}{\sqrt{2}}} \]
        7. lower-/.f64N/A

          \[\leadsto \color{blue}{\frac{\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)}{\sqrt{2}}} \]
        8. lower-*.f64N/A

          \[\leadsto \frac{\color{blue}{\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)}}{\sqrt{2}} \]
        9. +-commutativeN/A

          \[\leadsto \frac{\cos th \cdot \color{blue}{\left(a2 \cdot a2 + a1 \cdot a1\right)}}{\sqrt{2}} \]
        10. lift-*.f64N/A

          \[\leadsto \frac{\cos th \cdot \left(\color{blue}{a2 \cdot a2} + a1 \cdot a1\right)}{\sqrt{2}} \]
        11. lower-fma.f6499.6

          \[\leadsto \frac{\cos th \cdot \color{blue}{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}}{\sqrt{2}} \]
      4. Applied rewrites99.6%

        \[\leadsto \color{blue}{\frac{\cos th \cdot \mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}}} \]
      5. Add Preprocessing

      Alternative 5: 99.6% accurate, 1.9× speedup?

      \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right) \cdot \frac{\cos th}{\sqrt{2}} \end{array} \]
      a2_m = (fabs.f64 a2)
      a1_m = (fabs.f64 a1)
      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
       (* (fma a2_m a2_m (* a1_m a1_m)) (/ (cos th) (sqrt 2.0))))
      a2_m = fabs(a2);
      a1_m = fabs(a1);
      assert(a1_m < a2_m && a2_m < th);
      double code(double a1_m, double a2_m, double th) {
      	return fma(a2_m, a2_m, (a1_m * a1_m)) * (cos(th) / sqrt(2.0));
      }
      
      a2_m = abs(a2)
      a1_m = abs(a1)
      a1_m, a2_m, th = sort([a1_m, a2_m, th])
      function code(a1_m, a2_m, th)
      	return Float64(fma(a2_m, a2_m, Float64(a1_m * a1_m)) * Float64(cos(th) / sqrt(2.0)))
      end
      
      a2_m = N[Abs[a2], $MachinePrecision]
      a1_m = N[Abs[a1], $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 * a2$95$m + N[(a1$95$m * a1$95$m), $MachinePrecision]), $MachinePrecision] * N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
      
      \begin{array}{l}
      a2_m = \left|a2\right|
      \\
      a1_m = \left|a1\right|
      \\
      [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
      \\
      \mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right) \cdot \frac{\cos th}{\sqrt{2}}
      \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. Add Preprocessing
      3. Step-by-step derivation
        1. lift-+.f64N/A

          \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right)} \]
        2. lift-*.f64N/A

          \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right)} + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
        3. lift-*.f64N/A

          \[\leadsto \frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right)} \]
        4. distribute-lft-outN/A

          \[\leadsto \color{blue}{\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)} \]
        5. *-commutativeN/A

          \[\leadsto \color{blue}{\left(a1 \cdot a1 + a2 \cdot a2\right) \cdot \frac{\cos th}{\sqrt{2}}} \]
        6. lower-*.f64N/A

          \[\leadsto \color{blue}{\left(a1 \cdot a1 + a2 \cdot a2\right) \cdot \frac{\cos th}{\sqrt{2}}} \]
        7. +-commutativeN/A

          \[\leadsto \color{blue}{\left(a2 \cdot a2 + a1 \cdot a1\right)} \cdot \frac{\cos th}{\sqrt{2}} \]
        8. lift-*.f64N/A

          \[\leadsto \left(\color{blue}{a2 \cdot a2} + a1 \cdot a1\right) \cdot \frac{\cos th}{\sqrt{2}} \]
        9. lower-fma.f6499.5

          \[\leadsto \color{blue}{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)} \cdot \frac{\cos th}{\sqrt{2}} \]
      4. Applied rewrites99.5%

        \[\leadsto \color{blue}{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right) \cdot \frac{\cos th}{\sqrt{2}}} \]
      5. Add Preprocessing

      Alternative 6: 99.1% accurate, 2.0× speedup?

      \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \left(\frac{a2\_m}{\sqrt{2}} \cdot \cos th\right) \cdot a2\_m \end{array} \]
      a2_m = (fabs.f64 a2)
      a1_m = (fabs.f64 a1)
      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)) (cos th)) a2_m))
      a2_m = fabs(a2);
      a1_m = fabs(a1);
      assert(a1_m < a2_m && a2_m < th);
      double code(double a1_m, double a2_m, double th) {
      	return ((a2_m / sqrt(2.0)) * cos(th)) * a2_m;
      }
      
      a2_m =     private
      a1_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)) * cos(th)) * a2_m
      end function
      
      a2_m = Math.abs(a2);
      a1_m = Math.abs(a1);
      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)) * Math.cos(th)) * a2_m;
      }
      
      a2_m = math.fabs(a2)
      a1_m = math.fabs(a1)
      [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)) * math.cos(th)) * a2_m
      
      a2_m = abs(a2)
      a1_m = abs(a1)
      a1_m, a2_m, th = sort([a1_m, a2_m, th])
      function code(a1_m, a2_m, th)
      	return Float64(Float64(Float64(a2_m / sqrt(2.0)) * cos(th)) * a2_m)
      end
      
      a2_m = abs(a2);
      a1_m = abs(a1);
      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)) * cos(th)) * a2_m;
      end
      
      a2_m = N[Abs[a2], $MachinePrecision]
      a1_m = N[Abs[a1], $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[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * N[Cos[th], $MachinePrecision]), $MachinePrecision] * a2$95$m), $MachinePrecision]
      
      \begin{array}{l}
      a2_m = \left|a2\right|
      \\
      a1_m = \left|a1\right|
      \\
      [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
      \\
      \left(\frac{a2\_m}{\sqrt{2}} \cdot \cos th\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. Add Preprocessing
      3. Taylor expanded in a1 around 0

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

          \[\leadsto \frac{\color{blue}{\cos th \cdot {a2}^{2}}}{\sqrt{2}} \]
        2. unpow2N/A

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

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

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

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

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

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

          \[\leadsto \left(\cos th \cdot a2\right) \cdot \color{blue}{\frac{a2}{\sqrt{2}}} \]
        9. lower-sqrt.f6453.3

          \[\leadsto \left(\cos th \cdot a2\right) \cdot \frac{a2}{\color{blue}{\sqrt{2}}} \]
      5. Applied rewrites53.3%

        \[\leadsto \color{blue}{\left(\cos th \cdot a2\right) \cdot \frac{a2}{\sqrt{2}}} \]
      6. Step-by-step derivation
        1. Applied rewrites53.3%

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

        Alternative 7: 99.1% accurate, 2.0× speedup?

        \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \left(\cos th \cdot a2\_m\right) \cdot \frac{a2\_m}{\sqrt{2}} \end{array} \]
        a2_m = (fabs.f64 a2)
        a1_m = (fabs.f64 a1)
        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) (/ a2_m (sqrt 2.0))))
        a2_m = fabs(a2);
        a1_m = fabs(a1);
        assert(a1_m < a2_m && a2_m < th);
        double code(double a1_m, double a2_m, double th) {
        	return (cos(th) * a2_m) * (a2_m / sqrt(2.0));
        }
        
        a2_m =     private
        a1_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) * (a2_m / sqrt(2.0d0))
        end function
        
        a2_m = Math.abs(a2);
        a1_m = Math.abs(a1);
        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) * (a2_m / Math.sqrt(2.0));
        }
        
        a2_m = math.fabs(a2)
        a1_m = math.fabs(a1)
        [a1_m, a2_m, th] = sort([a1_m, a2_m, th])
        def code(a1_m, a2_m, th):
        	return (math.cos(th) * a2_m) * (a2_m / math.sqrt(2.0))
        
        a2_m = abs(a2)
        a1_m = abs(a1)
        a1_m, a2_m, th = sort([a1_m, a2_m, th])
        function code(a1_m, a2_m, th)
        	return Float64(Float64(cos(th) * a2_m) * Float64(a2_m / sqrt(2.0)))
        end
        
        a2_m = abs(a2);
        a1_m = abs(a1);
        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) * (a2_m / sqrt(2.0));
        end
        
        a2_m = N[Abs[a2], $MachinePrecision]
        a1_m = N[Abs[a1], $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] * a2$95$m), $MachinePrecision] * N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
        
        \begin{array}{l}
        a2_m = \left|a2\right|
        \\
        a1_m = \left|a1\right|
        \\
        [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
        \\
        \left(\cos th \cdot a2\_m\right) \cdot \frac{a2\_m}{\sqrt{2}}
        \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. Add Preprocessing
        3. Taylor expanded in a1 around 0

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

            \[\leadsto \frac{\color{blue}{\cos th \cdot {a2}^{2}}}{\sqrt{2}} \]
          2. unpow2N/A

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

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

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

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

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

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

            \[\leadsto \left(\cos th \cdot a2\right) \cdot \color{blue}{\frac{a2}{\sqrt{2}}} \]
          9. lower-sqrt.f6453.3

            \[\leadsto \left(\cos th \cdot a2\right) \cdot \frac{a2}{\color{blue}{\sqrt{2}}} \]
        5. Applied rewrites53.3%

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

        Alternative 8: 66.9% accurate, 8.1× speedup?

        \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \frac{\mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right)}{\sqrt{2}} \end{array} \]
        a2_m = (fabs.f64 a2)
        a1_m = (fabs.f64 a1)
        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
         (/ (fma a2_m a2_m (* a1_m a1_m)) (sqrt 2.0)))
        a2_m = fabs(a2);
        a1_m = fabs(a1);
        assert(a1_m < a2_m && a2_m < th);
        double code(double a1_m, double a2_m, double th) {
        	return fma(a2_m, a2_m, (a1_m * a1_m)) / sqrt(2.0);
        }
        
        a2_m = abs(a2)
        a1_m = abs(a1)
        a1_m, a2_m, th = sort([a1_m, a2_m, th])
        function code(a1_m, a2_m, th)
        	return Float64(fma(a2_m, a2_m, Float64(a1_m * a1_m)) / sqrt(2.0))
        end
        
        a2_m = N[Abs[a2], $MachinePrecision]
        a1_m = N[Abs[a1], $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 * a2$95$m + N[(a1$95$m * a1$95$m), $MachinePrecision]), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]
        
        \begin{array}{l}
        a2_m = \left|a2\right|
        \\
        a1_m = \left|a1\right|
        \\
        [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
        \\
        \frac{\mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right)}{\sqrt{2}}
        \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. Add Preprocessing
        3. Taylor expanded in th around 0

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

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

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

            \[\leadsto \frac{\color{blue}{{a2}^{2} + {a1}^{2}}}{\sqrt{2}} \]
          4. unpow2N/A

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

            \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(a2, a2, {a1}^{2}\right)}}{\sqrt{2}} \]
          6. unpow2N/A

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

            \[\leadsto \frac{\mathsf{fma}\left(a2, a2, \color{blue}{a1 \cdot a1}\right)}{\sqrt{2}} \]
          8. lower-sqrt.f6464.4

            \[\leadsto \frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\color{blue}{\sqrt{2}}} \]
        5. Applied rewrites64.4%

          \[\leadsto \color{blue}{\frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}}} \]
        6. Add Preprocessing

        Alternative 9: 66.7% accurate, 9.9× speedup?

        \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ a2\_m \cdot \frac{a2\_m}{\sqrt{2}} \end{array} \]
        a2_m = (fabs.f64 a2)
        a1_m = (fabs.f64 a1)
        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 (/ a2_m (sqrt 2.0))))
        a2_m = fabs(a2);
        a1_m = fabs(a1);
        assert(a1_m < a2_m && a2_m < th);
        double code(double a1_m, double a2_m, double th) {
        	return a2_m * (a2_m / sqrt(2.0));
        }
        
        a2_m =     private
        a1_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 * (a2_m / sqrt(2.0d0))
        end function
        
        a2_m = Math.abs(a2);
        a1_m = Math.abs(a1);
        assert a1_m < a2_m && a2_m < th;
        public static double code(double a1_m, double a2_m, double th) {
        	return a2_m * (a2_m / Math.sqrt(2.0));
        }
        
        a2_m = math.fabs(a2)
        a1_m = math.fabs(a1)
        [a1_m, a2_m, th] = sort([a1_m, a2_m, th])
        def code(a1_m, a2_m, th):
        	return a2_m * (a2_m / math.sqrt(2.0))
        
        a2_m = abs(a2)
        a1_m = abs(a1)
        a1_m, a2_m, th = sort([a1_m, a2_m, th])
        function code(a1_m, a2_m, th)
        	return Float64(a2_m * Float64(a2_m / sqrt(2.0)))
        end
        
        a2_m = abs(a2);
        a1_m = abs(a1);
        a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
        function tmp = code(a1_m, a2_m, th)
        	tmp = a2_m * (a2_m / sqrt(2.0));
        end
        
        a2_m = N[Abs[a2], $MachinePrecision]
        a1_m = N[Abs[a1], $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[(a2$95$m * N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
        
        \begin{array}{l}
        a2_m = \left|a2\right|
        \\
        a1_m = \left|a1\right|
        \\
        [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
        \\
        a2\_m \cdot \frac{a2\_m}{\sqrt{2}}
        \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. Add Preprocessing
        3. Taylor expanded in th around 0

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

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

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

            \[\leadsto \frac{\color{blue}{{a2}^{2} + {a1}^{2}}}{\sqrt{2}} \]
          4. unpow2N/A

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

            \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(a2, a2, {a1}^{2}\right)}}{\sqrt{2}} \]
          6. unpow2N/A

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

            \[\leadsto \frac{\mathsf{fma}\left(a2, a2, \color{blue}{a1 \cdot a1}\right)}{\sqrt{2}} \]
          8. lower-sqrt.f6464.4

            \[\leadsto \frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\color{blue}{\sqrt{2}}} \]
        5. Applied rewrites64.4%

          \[\leadsto \color{blue}{\frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\sqrt{2}}} \]
        6. Taylor expanded in a1 around 0

          \[\leadsto \frac{{a2}^{2}}{\color{blue}{\sqrt{2}}} \]
        7. Step-by-step derivation
          1. Applied rewrites35.7%

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

          Alternative 10: 13.7% accurate, 9.9× speedup?

          \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ a1\_m \cdot \frac{a1\_m}{\sqrt{2}} \end{array} \]
          a2_m = (fabs.f64 a2)
          a1_m = (fabs.f64 a1)
          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 (/ a1_m (sqrt 2.0))))
          a2_m = fabs(a2);
          a1_m = fabs(a1);
          assert(a1_m < a2_m && a2_m < th);
          double code(double a1_m, double a2_m, double th) {
          	return a1_m * (a1_m / sqrt(2.0));
          }
          
          a2_m =     private
          a1_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 * (a1_m / sqrt(2.0d0))
          end function
          
          a2_m = Math.abs(a2);
          a1_m = Math.abs(a1);
          assert a1_m < a2_m && a2_m < th;
          public static double code(double a1_m, double a2_m, double th) {
          	return a1_m * (a1_m / Math.sqrt(2.0));
          }
          
          a2_m = math.fabs(a2)
          a1_m = math.fabs(a1)
          [a1_m, a2_m, th] = sort([a1_m, a2_m, th])
          def code(a1_m, a2_m, th):
          	return a1_m * (a1_m / math.sqrt(2.0))
          
          a2_m = abs(a2)
          a1_m = abs(a1)
          a1_m, a2_m, th = sort([a1_m, a2_m, th])
          function code(a1_m, a2_m, th)
          	return Float64(a1_m * Float64(a1_m / sqrt(2.0)))
          end
          
          a2_m = abs(a2);
          a1_m = abs(a1);
          a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
          function tmp = code(a1_m, a2_m, th)
          	tmp = a1_m * (a1_m / sqrt(2.0));
          end
          
          a2_m = N[Abs[a2], $MachinePrecision]
          a1_m = N[Abs[a1], $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[(a1$95$m * N[(a1$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
          
          \begin{array}{l}
          a2_m = \left|a2\right|
          \\
          a1_m = \left|a1\right|
          \\
          [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
          \\
          a1\_m \cdot \frac{a1\_m}{\sqrt{2}}
          \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. Add Preprocessing
          3. Taylor expanded in th around 0

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

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

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

              \[\leadsto \frac{\color{blue}{{a2}^{2} + {a1}^{2}}}{\sqrt{2}} \]
            4. unpow2N/A

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

              \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(a2, a2, {a1}^{2}\right)}}{\sqrt{2}} \]
            6. unpow2N/A

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

              \[\leadsto \frac{\mathsf{fma}\left(a2, a2, \color{blue}{a1 \cdot a1}\right)}{\sqrt{2}} \]
            8. lower-sqrt.f6464.4

              \[\leadsto \frac{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)}{\color{blue}{\sqrt{2}}} \]
          5. Applied rewrites64.4%

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

            \[\leadsto \frac{{a1}^{2}}{\color{blue}{\sqrt{2}}} \]
          7. Step-by-step derivation
            1. Applied rewrites38.3%

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

            Reproduce

            ?
            herbie shell --seed 2025016 
            (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))))