Migdal et al, Equation (64)

Percentage Accurate: 99.6% → 99.6%
Time: 7.9s
Alternatives: 9
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));
}
real(8) function code(a1, a2, th)
    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 9 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));
}
real(8) function code(a1, a2, th)
    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?

\[\begin{array}{l} a2_m = \left|a2\right| \\ [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\ \\ \mathsf{fma}\left(\frac{\cos th}{\sqrt{2}}, a1 \cdot a1, \left(\frac{a2\_m}{\sqrt{2}} \cdot a2\_m\right) \cdot \cos th\right) \end{array} \]
a2_m = (fabs.f64 a2)
NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
(FPCore (a1 a2_m th)
 :precision binary64
 (fma
  (/ (cos th) (sqrt 2.0))
  (* a1 a1)
  (* (* (/ a2_m (sqrt 2.0)) a2_m) (cos th))))
a2_m = fabs(a2);
assert(a1 < a2_m && a2_m < th);
double code(double a1, double a2_m, double th) {
	return fma((cos(th) / sqrt(2.0)), (a1 * a1), (((a2_m / sqrt(2.0)) * a2_m) * cos(th)));
}
a2_m = abs(a2)
a1, a2_m, th = sort([a1, a2_m, th])
function code(a1, a2_m, th)
	return fma(Float64(cos(th) / sqrt(2.0)), Float64(a1 * a1), Float64(Float64(Float64(a2_m / sqrt(2.0)) * a2_m) * cos(th)))
end
a2_m = N[Abs[a2], $MachinePrecision]
NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
code[a1_, a2$95$m_, th_] := N[(N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * N[(a1 * a1), $MachinePrecision] + N[(N[(N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * a2$95$m), $MachinePrecision] * N[Cos[th], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a2_m = \left|a2\right|
\\
[a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\
\\
\mathsf{fma}\left(\frac{\cos th}{\sqrt{2}}, a1 \cdot a1, \left(\frac{a2\_m}{\sqrt{2}} \cdot a2\_m\right) \cdot \cos th\right)
\end{array}
Derivation
  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. 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. lower-fma.f6499.6

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

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

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

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

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

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

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

      \[\leadsto \mathsf{fma}\left(\frac{\cos th}{\sqrt{2}}, a1 \cdot a1, \frac{\color{blue}{1 \cdot \left(a2 \cdot a2\right)}}{\sqrt{2}} \cdot \cos th\right) \]
    11. associate-*l/N/A

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

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

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

      \[\leadsto \mathsf{fma}\left(\frac{\cos th}{\sqrt{2}}, a1 \cdot a1, \color{blue}{\left(\left(\frac{1}{\sqrt{2}} \cdot a2\right) \cdot a2\right)} \cdot \cos th\right) \]
    15. associate-*l/N/A

      \[\leadsto \mathsf{fma}\left(\frac{\cos th}{\sqrt{2}}, a1 \cdot a1, \left(\color{blue}{\frac{1 \cdot a2}{\sqrt{2}}} \cdot a2\right) \cdot \cos th\right) \]
    16. *-lft-identityN/A

      \[\leadsto \mathsf{fma}\left(\frac{\cos th}{\sqrt{2}}, a1 \cdot a1, \left(\frac{\color{blue}{a2}}{\sqrt{2}} \cdot a2\right) \cdot \cos th\right) \]
    17. lower-/.f6499.7

      \[\leadsto \mathsf{fma}\left(\frac{\cos th}{\sqrt{2}}, a1 \cdot a1, \left(\color{blue}{\frac{a2}{\sqrt{2}}} \cdot a2\right) \cdot \cos th\right) \]
  4. Applied rewrites99.7%

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

Alternative 2: 77.1% accurate, 0.8× speedup?

\[\begin{array}{l} a2_m = \left|a2\right| \\ [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\ \\ \begin{array}{l} t_1 := \frac{\cos th}{\sqrt{2}}\\ \mathbf{if}\;\left(a2\_m \cdot a2\_m\right) \cdot t\_1 + \left(a1 \cdot a1\right) \cdot t\_1 \leq -5 \cdot 10^{-205}:\\ \;\;\;\;\left(\mathsf{fma}\left(-0.5, th \cdot th, 1\right) \cdot a2\_m\right) \cdot \frac{a2\_m}{\sqrt{2}}\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \frac{a2\_m}{\frac{\sqrt{2}}{a2\_m}}\right)\\ \end{array} \end{array} \]
a2_m = (fabs.f64 a2)
NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
(FPCore (a1 a2_m th)
 :precision binary64
 (let* ((t_1 (/ (cos th) (sqrt 2.0))))
   (if (<= (+ (* (* a2_m a2_m) t_1) (* (* a1 a1) t_1)) -5e-205)
     (* (* (fma -0.5 (* th th) 1.0) a2_m) (/ a2_m (sqrt 2.0)))
     (fma (/ a1 (sqrt 2.0)) a1 (/ a2_m (/ (sqrt 2.0) a2_m))))))
a2_m = fabs(a2);
assert(a1 < a2_m && a2_m < th);
double code(double a1, double a2_m, double th) {
	double t_1 = cos(th) / sqrt(2.0);
	double tmp;
	if ((((a2_m * a2_m) * t_1) + ((a1 * a1) * t_1)) <= -5e-205) {
		tmp = (fma(-0.5, (th * th), 1.0) * a2_m) * (a2_m / sqrt(2.0));
	} else {
		tmp = fma((a1 / sqrt(2.0)), a1, (a2_m / (sqrt(2.0) / a2_m)));
	}
	return tmp;
}
a2_m = abs(a2)
a1, a2_m, th = sort([a1, a2_m, th])
function code(a1, a2_m, th)
	t_1 = Float64(cos(th) / sqrt(2.0))
	tmp = 0.0
	if (Float64(Float64(Float64(a2_m * a2_m) * t_1) + Float64(Float64(a1 * a1) * t_1)) <= -5e-205)
		tmp = Float64(Float64(fma(-0.5, Float64(th * th), 1.0) * a2_m) * Float64(a2_m / sqrt(2.0)));
	else
		tmp = fma(Float64(a1 / sqrt(2.0)), a1, Float64(a2_m / Float64(sqrt(2.0) / a2_m)));
	end
	return tmp
end
a2_m = N[Abs[a2], $MachinePrecision]
NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
code[a1_, a2$95$m_, th_] := Block[{t$95$1 = N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[(N[(N[(a2$95$m * a2$95$m), $MachinePrecision] * t$95$1), $MachinePrecision] + N[(N[(a1 * a1), $MachinePrecision] * t$95$1), $MachinePrecision]), $MachinePrecision], -5e-205], N[(N[(N[(-0.5 * N[(th * th), $MachinePrecision] + 1.0), $MachinePrecision] * a2$95$m), $MachinePrecision] * N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(a1 / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * a1 + N[(a2$95$m / N[(N[Sqrt[2.0], $MachinePrecision] / a2$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
a2_m = \left|a2\right|
\\
[a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\
\\
\begin{array}{l}
t_1 := \frac{\cos th}{\sqrt{2}}\\
\mathbf{if}\;\left(a2\_m \cdot a2\_m\right) \cdot t\_1 + \left(a1 \cdot a1\right) \cdot t\_1 \leq -5 \cdot 10^{-205}:\\
\;\;\;\;\left(\mathsf{fma}\left(-0.5, th \cdot th, 1\right) \cdot a2\_m\right) \cdot \frac{a2\_m}{\sqrt{2}}\\

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


\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))) < -5.00000000000000001e-205

    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.f6456.2

        \[\leadsto \left(\cos th \cdot a2\right) \cdot \frac{a2}{\color{blue}{\sqrt{2}}} \]
    5. Applied rewrites56.2%

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

      \[\leadsto \left(\left(1 + \frac{-1}{2} \cdot {th}^{2}\right) \cdot a2\right) \cdot \frac{a2}{\sqrt{2}} \]
    7. Step-by-step derivation
      1. Applied rewrites45.8%

        \[\leadsto \left(\mathsf{fma}\left(-0.5, th \cdot th, 1\right) \cdot a2\right) \cdot \frac{a2}{\sqrt{2}} \]

      if -5.00000000000000001e-205 < (+.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 99.7%

        \[\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
      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. unpow2N/A

          \[\leadsto \frac{\color{blue}{a1 \cdot a1}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}} \]
        2. associate-*l/N/A

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

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

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

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

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

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

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

          \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \color{blue}{\frac{a2}{\sqrt{2}}} \cdot a2\right) \]
        10. lower-sqrt.f6486.6

          \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \frac{a2}{\color{blue}{\sqrt{2}}} \cdot a2\right) \]
      5. Applied rewrites86.6%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \frac{a2}{\sqrt{2}} \cdot a2\right)} \]
      6. Step-by-step derivation
        1. Applied rewrites86.6%

          \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \frac{a2}{\frac{\sqrt{2}}{a2}}\right) \]
      7. Recombined 2 regimes into one program.
      8. Final simplification75.8%

        \[\leadsto \begin{array}{l} \mathbf{if}\;\left(a2 \cdot a2\right) \cdot \frac{\cos th}{\sqrt{2}} + \left(a1 \cdot a1\right) \cdot \frac{\cos th}{\sqrt{2}} \leq -5 \cdot 10^{-205}:\\ \;\;\;\;\left(\mathsf{fma}\left(-0.5, th \cdot th, 1\right) \cdot a2\right) \cdot \frac{a2}{\sqrt{2}}\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \frac{a2}{\frac{\sqrt{2}}{a2}}\right)\\ \end{array} \]
      9. Add Preprocessing

      Alternative 3: 63.6% accurate, 0.8× speedup?

      \[\begin{array}{l} a2_m = \left|a2\right| \\ [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\ \\ \begin{array}{l} t_1 := \frac{a2\_m}{\sqrt{2}}\\ t_2 := \frac{\cos th}{\sqrt{2}}\\ \mathbf{if}\;\left(a2\_m \cdot a2\_m\right) \cdot t\_2 + \left(a1 \cdot a1\right) \cdot t\_2 \leq -5 \cdot 10^{-205}:\\ \;\;\;\;\left(\mathsf{fma}\left(-0.5, th \cdot th, 1\right) \cdot a2\_m\right) \cdot t\_1\\ \mathbf{else}:\\ \;\;\;\;t\_1 \cdot a2\_m\\ \end{array} \end{array} \]
      a2_m = (fabs.f64 a2)
      NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
      (FPCore (a1 a2_m th)
       :precision binary64
       (let* ((t_1 (/ a2_m (sqrt 2.0))) (t_2 (/ (cos th) (sqrt 2.0))))
         (if (<= (+ (* (* a2_m a2_m) t_2) (* (* a1 a1) t_2)) -5e-205)
           (* (* (fma -0.5 (* th th) 1.0) a2_m) t_1)
           (* t_1 a2_m))))
      a2_m = fabs(a2);
      assert(a1 < a2_m && a2_m < th);
      double code(double a1, double a2_m, double th) {
      	double t_1 = a2_m / sqrt(2.0);
      	double t_2 = cos(th) / sqrt(2.0);
      	double tmp;
      	if ((((a2_m * a2_m) * t_2) + ((a1 * a1) * t_2)) <= -5e-205) {
      		tmp = (fma(-0.5, (th * th), 1.0) * a2_m) * t_1;
      	} else {
      		tmp = t_1 * a2_m;
      	}
      	return tmp;
      }
      
      a2_m = abs(a2)
      a1, a2_m, th = sort([a1, a2_m, th])
      function code(a1, a2_m, th)
      	t_1 = Float64(a2_m / sqrt(2.0))
      	t_2 = Float64(cos(th) / sqrt(2.0))
      	tmp = 0.0
      	if (Float64(Float64(Float64(a2_m * a2_m) * t_2) + Float64(Float64(a1 * a1) * t_2)) <= -5e-205)
      		tmp = Float64(Float64(fma(-0.5, Float64(th * th), 1.0) * a2_m) * t_1);
      	else
      		tmp = Float64(t_1 * a2_m);
      	end
      	return tmp
      end
      
      a2_m = N[Abs[a2], $MachinePrecision]
      NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
      code[a1_, a2$95$m_, th_] := Block[{t$95$1 = N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[(N[(N[(a2$95$m * a2$95$m), $MachinePrecision] * t$95$2), $MachinePrecision] + N[(N[(a1 * a1), $MachinePrecision] * t$95$2), $MachinePrecision]), $MachinePrecision], -5e-205], N[(N[(N[(-0.5 * N[(th * th), $MachinePrecision] + 1.0), $MachinePrecision] * a2$95$m), $MachinePrecision] * t$95$1), $MachinePrecision], N[(t$95$1 * a2$95$m), $MachinePrecision]]]]
      
      \begin{array}{l}
      a2_m = \left|a2\right|
      \\
      [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\
      \\
      \begin{array}{l}
      t_1 := \frac{a2\_m}{\sqrt{2}}\\
      t_2 := \frac{\cos th}{\sqrt{2}}\\
      \mathbf{if}\;\left(a2\_m \cdot a2\_m\right) \cdot t\_2 + \left(a1 \cdot a1\right) \cdot t\_2 \leq -5 \cdot 10^{-205}:\\
      \;\;\;\;\left(\mathsf{fma}\left(-0.5, th \cdot th, 1\right) \cdot a2\_m\right) \cdot t\_1\\
      
      \mathbf{else}:\\
      \;\;\;\;t\_1 \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))) < -5.00000000000000001e-205

        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.f6456.2

            \[\leadsto \left(\cos th \cdot a2\right) \cdot \frac{a2}{\color{blue}{\sqrt{2}}} \]
        5. Applied rewrites56.2%

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

          \[\leadsto \left(\left(1 + \frac{-1}{2} \cdot {th}^{2}\right) \cdot a2\right) \cdot \frac{a2}{\sqrt{2}} \]
        7. Step-by-step derivation
          1. Applied rewrites45.8%

            \[\leadsto \left(\mathsf{fma}\left(-0.5, th \cdot th, 1\right) \cdot a2\right) \cdot \frac{a2}{\sqrt{2}} \]

          if -5.00000000000000001e-205 < (+.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 99.7%

            \[\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
          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. unpow2N/A

              \[\leadsto \frac{\color{blue}{a1 \cdot a1}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}} \]
            2. associate-*l/N/A

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

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

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

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

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

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

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

              \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \color{blue}{\frac{a2}{\sqrt{2}}} \cdot a2\right) \]
            10. lower-sqrt.f6486.6

              \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \frac{a2}{\color{blue}{\sqrt{2}}} \cdot a2\right) \]
          5. Applied rewrites86.6%

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

            \[\leadsto \frac{{a2}^{2}}{\color{blue}{\sqrt{2}}} \]
          7. Step-by-step derivation
            1. Applied rewrites57.3%

              \[\leadsto a2 \cdot \color{blue}{\frac{a2}{\sqrt{2}}} \]
          8. Recombined 2 regimes into one program.
          9. Final simplification54.3%

            \[\leadsto \begin{array}{l} \mathbf{if}\;\left(a2 \cdot a2\right) \cdot \frac{\cos th}{\sqrt{2}} + \left(a1 \cdot a1\right) \cdot \frac{\cos th}{\sqrt{2}} \leq -5 \cdot 10^{-205}:\\ \;\;\;\;\left(\mathsf{fma}\left(-0.5, th \cdot th, 1\right) \cdot a2\right) \cdot \frac{a2}{\sqrt{2}}\\ \mathbf{else}:\\ \;\;\;\;\frac{a2}{\sqrt{2}} \cdot a2\\ \end{array} \]
          10. Add Preprocessing

          Alternative 4: 63.6% accurate, 0.8× speedup?

          \[\begin{array}{l} a2_m = \left|a2\right| \\ [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\ \\ \begin{array}{l} t_1 := \frac{a2\_m}{\sqrt{2}}\\ t_2 := \frac{\cos th}{\sqrt{2}}\\ \mathbf{if}\;\left(a2\_m \cdot a2\_m\right) \cdot t\_2 + \left(a1 \cdot a1\right) \cdot t\_2 \leq -5 \cdot 10^{-205}:\\ \;\;\;\;\left(\left(\left(th \cdot th\right) \cdot -0.5\right) \cdot a2\_m\right) \cdot t\_1\\ \mathbf{else}:\\ \;\;\;\;t\_1 \cdot a2\_m\\ \end{array} \end{array} \]
          a2_m = (fabs.f64 a2)
          NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
          (FPCore (a1 a2_m th)
           :precision binary64
           (let* ((t_1 (/ a2_m (sqrt 2.0))) (t_2 (/ (cos th) (sqrt 2.0))))
             (if (<= (+ (* (* a2_m a2_m) t_2) (* (* a1 a1) t_2)) -5e-205)
               (* (* (* (* th th) -0.5) a2_m) t_1)
               (* t_1 a2_m))))
          a2_m = fabs(a2);
          assert(a1 < a2_m && a2_m < th);
          double code(double a1, double a2_m, double th) {
          	double t_1 = a2_m / sqrt(2.0);
          	double t_2 = cos(th) / sqrt(2.0);
          	double tmp;
          	if ((((a2_m * a2_m) * t_2) + ((a1 * a1) * t_2)) <= -5e-205) {
          		tmp = (((th * th) * -0.5) * a2_m) * t_1;
          	} else {
          		tmp = t_1 * a2_m;
          	}
          	return tmp;
          }
          
          a2_m = abs(a2)
          NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
          real(8) function code(a1, a2_m, th)
              real(8), intent (in) :: a1
              real(8), intent (in) :: a2_m
              real(8), intent (in) :: th
              real(8) :: t_1
              real(8) :: t_2
              real(8) :: tmp
              t_1 = a2_m / sqrt(2.0d0)
              t_2 = cos(th) / sqrt(2.0d0)
              if ((((a2_m * a2_m) * t_2) + ((a1 * a1) * t_2)) <= (-5d-205)) then
                  tmp = (((th * th) * (-0.5d0)) * a2_m) * t_1
              else
                  tmp = t_1 * a2_m
              end if
              code = tmp
          end function
          
          a2_m = Math.abs(a2);
          assert a1 < a2_m && a2_m < th;
          public static double code(double a1, double a2_m, double th) {
          	double t_1 = a2_m / Math.sqrt(2.0);
          	double t_2 = Math.cos(th) / Math.sqrt(2.0);
          	double tmp;
          	if ((((a2_m * a2_m) * t_2) + ((a1 * a1) * t_2)) <= -5e-205) {
          		tmp = (((th * th) * -0.5) * a2_m) * t_1;
          	} else {
          		tmp = t_1 * a2_m;
          	}
          	return tmp;
          }
          
          a2_m = math.fabs(a2)
          [a1, a2_m, th] = sort([a1, a2_m, th])
          def code(a1, a2_m, th):
          	t_1 = a2_m / math.sqrt(2.0)
          	t_2 = math.cos(th) / math.sqrt(2.0)
          	tmp = 0
          	if (((a2_m * a2_m) * t_2) + ((a1 * a1) * t_2)) <= -5e-205:
          		tmp = (((th * th) * -0.5) * a2_m) * t_1
          	else:
          		tmp = t_1 * a2_m
          	return tmp
          
          a2_m = abs(a2)
          a1, a2_m, th = sort([a1, a2_m, th])
          function code(a1, a2_m, th)
          	t_1 = Float64(a2_m / sqrt(2.0))
          	t_2 = Float64(cos(th) / sqrt(2.0))
          	tmp = 0.0
          	if (Float64(Float64(Float64(a2_m * a2_m) * t_2) + Float64(Float64(a1 * a1) * t_2)) <= -5e-205)
          		tmp = Float64(Float64(Float64(Float64(th * th) * -0.5) * a2_m) * t_1);
          	else
          		tmp = Float64(t_1 * a2_m);
          	end
          	return tmp
          end
          
          a2_m = abs(a2);
          a1, a2_m, th = num2cell(sort([a1, a2_m, th])){:}
          function tmp_2 = code(a1, a2_m, th)
          	t_1 = a2_m / sqrt(2.0);
          	t_2 = cos(th) / sqrt(2.0);
          	tmp = 0.0;
          	if ((((a2_m * a2_m) * t_2) + ((a1 * a1) * t_2)) <= -5e-205)
          		tmp = (((th * th) * -0.5) * a2_m) * t_1;
          	else
          		tmp = t_1 * a2_m;
          	end
          	tmp_2 = tmp;
          end
          
          a2_m = N[Abs[a2], $MachinePrecision]
          NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
          code[a1_, a2$95$m_, th_] := Block[{t$95$1 = N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[(N[(N[(a2$95$m * a2$95$m), $MachinePrecision] * t$95$2), $MachinePrecision] + N[(N[(a1 * a1), $MachinePrecision] * t$95$2), $MachinePrecision]), $MachinePrecision], -5e-205], N[(N[(N[(N[(th * th), $MachinePrecision] * -0.5), $MachinePrecision] * a2$95$m), $MachinePrecision] * t$95$1), $MachinePrecision], N[(t$95$1 * a2$95$m), $MachinePrecision]]]]
          
          \begin{array}{l}
          a2_m = \left|a2\right|
          \\
          [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\
          \\
          \begin{array}{l}
          t_1 := \frac{a2\_m}{\sqrt{2}}\\
          t_2 := \frac{\cos th}{\sqrt{2}}\\
          \mathbf{if}\;\left(a2\_m \cdot a2\_m\right) \cdot t\_2 + \left(a1 \cdot a1\right) \cdot t\_2 \leq -5 \cdot 10^{-205}:\\
          \;\;\;\;\left(\left(\left(th \cdot th\right) \cdot -0.5\right) \cdot a2\_m\right) \cdot t\_1\\
          
          \mathbf{else}:\\
          \;\;\;\;t\_1 \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))) < -5.00000000000000001e-205

            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.f6456.2

                \[\leadsto \left(\cos th \cdot a2\right) \cdot \frac{a2}{\color{blue}{\sqrt{2}}} \]
            5. Applied rewrites56.2%

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

              \[\leadsto \left(\left(1 + \frac{-1}{2} \cdot {th}^{2}\right) \cdot a2\right) \cdot \frac{a2}{\sqrt{2}} \]
            7. Step-by-step derivation
              1. Applied rewrites45.8%

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

                \[\leadsto \left(\left(\frac{-1}{2} \cdot {th}^{2}\right) \cdot a2\right) \cdot \frac{a2}{\sqrt{2}} \]
              3. Step-by-step derivation
                1. Applied rewrites45.8%

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

                if -5.00000000000000001e-205 < (+.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 99.7%

                  \[\frac{\cos th}{\sqrt{2}} \cdot \left(a1 \cdot a1\right) + \frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) \]
                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. unpow2N/A

                    \[\leadsto \frac{\color{blue}{a1 \cdot a1}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}} \]
                  2. associate-*l/N/A

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

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

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

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

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

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

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

                    \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \color{blue}{\frac{a2}{\sqrt{2}}} \cdot a2\right) \]
                  10. lower-sqrt.f6486.6

                    \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \frac{a2}{\color{blue}{\sqrt{2}}} \cdot a2\right) \]
                5. Applied rewrites86.6%

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

                  \[\leadsto \frac{{a2}^{2}}{\color{blue}{\sqrt{2}}} \]
                7. Step-by-step derivation
                  1. Applied rewrites57.3%

                    \[\leadsto a2 \cdot \color{blue}{\frac{a2}{\sqrt{2}}} \]
                8. Recombined 2 regimes into one program.
                9. Final simplification54.3%

                  \[\leadsto \begin{array}{l} \mathbf{if}\;\left(a2 \cdot a2\right) \cdot \frac{\cos th}{\sqrt{2}} + \left(a1 \cdot a1\right) \cdot \frac{\cos th}{\sqrt{2}} \leq -5 \cdot 10^{-205}:\\ \;\;\;\;\left(\left(\left(th \cdot th\right) \cdot -0.5\right) \cdot a2\right) \cdot \frac{a2}{\sqrt{2}}\\ \mathbf{else}:\\ \;\;\;\;\frac{a2}{\sqrt{2}} \cdot a2\\ \end{array} \]
                10. Add Preprocessing

                Alternative 5: 99.6% accurate, 1.9× speedup?

                \[\begin{array}{l} a2_m = \left|a2\right| \\ [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\ \\ \frac{\mathsf{fma}\left(a2\_m, a2\_m, a1 \cdot a1\right)}{\sqrt{2}} \cdot \cos th \end{array} \]
                a2_m = (fabs.f64 a2)
                NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                (FPCore (a1 a2_m th)
                 :precision binary64
                 (* (/ (fma a2_m a2_m (* a1 a1)) (sqrt 2.0)) (cos th)))
                a2_m = fabs(a2);
                assert(a1 < a2_m && a2_m < th);
                double code(double a1, double a2_m, double th) {
                	return (fma(a2_m, a2_m, (a1 * a1)) / sqrt(2.0)) * cos(th);
                }
                
                a2_m = abs(a2)
                a1, a2_m, th = sort([a1, a2_m, th])
                function code(a1, a2_m, th)
                	return Float64(Float64(fma(a2_m, a2_m, Float64(a1 * a1)) / sqrt(2.0)) * cos(th))
                end
                
                a2_m = N[Abs[a2], $MachinePrecision]
                NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                code[a1_, a2$95$m_, th_] := N[(N[(N[(a2$95$m * a2$95$m + N[(a1 * a1), $MachinePrecision]), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * N[Cos[th], $MachinePrecision]), $MachinePrecision]
                
                \begin{array}{l}
                a2_m = \left|a2\right|
                \\
                [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\
                \\
                \frac{\mathsf{fma}\left(a2\_m, a2\_m, a1 \cdot a1\right)}{\sqrt{2}} \cdot \cos th
                \end{array}
                
                Derivation
                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. 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. div-invN/A

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

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

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

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

                    \[\leadsto \color{blue}{\frac{1 \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)}{\sqrt{2}}} \cdot \cos th \]
                  11. *-lft-identityN/A

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

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

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

                    \[\leadsto \frac{\color{blue}{a2 \cdot a2} + a1 \cdot a1}{\sqrt{2}} \cdot \cos th \]
                  15. lower-fma.f6499.6

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

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

                Alternative 6: 77.9% accurate, 2.0× speedup?

                \[\begin{array}{l} a2_m = \left|a2\right| \\ [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\ \\ \left(\frac{a2\_m}{\sqrt{2}} \cdot a2\_m\right) \cdot \cos th \end{array} \]
                a2_m = (fabs.f64 a2)
                NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                (FPCore (a1 a2_m th)
                 :precision binary64
                 (* (* (/ a2_m (sqrt 2.0)) a2_m) (cos th)))
                a2_m = fabs(a2);
                assert(a1 < a2_m && a2_m < th);
                double code(double a1, double a2_m, double th) {
                	return ((a2_m / sqrt(2.0)) * a2_m) * cos(th);
                }
                
                a2_m = abs(a2)
                NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                real(8) function code(a1, a2_m, th)
                    real(8), intent (in) :: a1
                    real(8), intent (in) :: a2_m
                    real(8), intent (in) :: th
                    code = ((a2_m / sqrt(2.0d0)) * a2_m) * cos(th)
                end function
                
                a2_m = Math.abs(a2);
                assert a1 < a2_m && a2_m < th;
                public static double code(double a1, double a2_m, double th) {
                	return ((a2_m / Math.sqrt(2.0)) * a2_m) * Math.cos(th);
                }
                
                a2_m = math.fabs(a2)
                [a1, a2_m, th] = sort([a1, a2_m, th])
                def code(a1, a2_m, th):
                	return ((a2_m / math.sqrt(2.0)) * a2_m) * math.cos(th)
                
                a2_m = abs(a2)
                a1, a2_m, th = sort([a1, a2_m, th])
                function code(a1, a2_m, th)
                	return Float64(Float64(Float64(a2_m / sqrt(2.0)) * a2_m) * cos(th))
                end
                
                a2_m = abs(a2);
                a1, a2_m, th = num2cell(sort([a1, a2_m, th])){:}
                function tmp = code(a1, a2_m, th)
                	tmp = ((a2_m / sqrt(2.0)) * a2_m) * cos(th);
                end
                
                a2_m = N[Abs[a2], $MachinePrecision]
                NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                code[a1_, a2$95$m_, th_] := N[(N[(N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * a2$95$m), $MachinePrecision] * N[Cos[th], $MachinePrecision]), $MachinePrecision]
                
                \begin{array}{l}
                a2_m = \left|a2\right|
                \\
                [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\
                \\
                \left(\frac{a2\_m}{\sqrt{2}} \cdot a2\_m\right) \cdot \cos th
                \end{array}
                
                Derivation
                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.f6462.1

                    \[\leadsto \left(\cos th \cdot a2\right) \cdot \frac{a2}{\color{blue}{\sqrt{2}}} \]
                5. Applied rewrites62.1%

                  \[\leadsto \color{blue}{\left(\cos th \cdot a2\right) \cdot \frac{a2}{\sqrt{2}}} \]
                6. Step-by-step derivation
                  1. Applied rewrites62.1%

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

                  Alternative 7: 77.9% accurate, 2.0× speedup?

                  \[\begin{array}{l} a2_m = \left|a2\right| \\ [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\ \\ \left(a2\_m \cdot \cos th\right) \cdot \frac{a2\_m}{\sqrt{2}} \end{array} \]
                  a2_m = (fabs.f64 a2)
                  NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                  (FPCore (a1 a2_m th)
                   :precision binary64
                   (* (* a2_m (cos th)) (/ a2_m (sqrt 2.0))))
                  a2_m = fabs(a2);
                  assert(a1 < a2_m && a2_m < th);
                  double code(double a1, double a2_m, double th) {
                  	return (a2_m * cos(th)) * (a2_m / sqrt(2.0));
                  }
                  
                  a2_m = abs(a2)
                  NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                  real(8) function code(a1, a2_m, th)
                      real(8), intent (in) :: a1
                      real(8), intent (in) :: a2_m
                      real(8), intent (in) :: th
                      code = (a2_m * cos(th)) * (a2_m / sqrt(2.0d0))
                  end function
                  
                  a2_m = Math.abs(a2);
                  assert a1 < a2_m && a2_m < th;
                  public static double code(double a1, double a2_m, double th) {
                  	return (a2_m * Math.cos(th)) * (a2_m / Math.sqrt(2.0));
                  }
                  
                  a2_m = math.fabs(a2)
                  [a1, a2_m, th] = sort([a1, a2_m, th])
                  def code(a1, a2_m, th):
                  	return (a2_m * math.cos(th)) * (a2_m / math.sqrt(2.0))
                  
                  a2_m = abs(a2)
                  a1, a2_m, th = sort([a1, a2_m, th])
                  function code(a1, a2_m, th)
                  	return Float64(Float64(a2_m * cos(th)) * Float64(a2_m / sqrt(2.0)))
                  end
                  
                  a2_m = abs(a2);
                  a1, a2_m, th = num2cell(sort([a1, a2_m, th])){:}
                  function tmp = code(a1, a2_m, th)
                  	tmp = (a2_m * cos(th)) * (a2_m / sqrt(2.0));
                  end
                  
                  a2_m = N[Abs[a2], $MachinePrecision]
                  NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                  code[a1_, a2$95$m_, th_] := N[(N[(a2$95$m * N[Cos[th], $MachinePrecision]), $MachinePrecision] * N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
                  
                  \begin{array}{l}
                  a2_m = \left|a2\right|
                  \\
                  [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\
                  \\
                  \left(a2\_m \cdot \cos th\right) \cdot \frac{a2\_m}{\sqrt{2}}
                  \end{array}
                  
                  Derivation
                  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.f6462.1

                      \[\leadsto \left(\cos th \cdot a2\right) \cdot \frac{a2}{\color{blue}{\sqrt{2}}} \]
                  5. Applied rewrites62.1%

                    \[\leadsto \color{blue}{\left(\cos th \cdot a2\right) \cdot \frac{a2}{\sqrt{2}}} \]
                  6. Final simplification62.1%

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

                  Alternative 8: 53.3% accurate, 9.9× speedup?

                  \[\begin{array}{l} a2_m = \left|a2\right| \\ [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\ \\ \frac{a2\_m}{\sqrt{2}} \cdot a2\_m \end{array} \]
                  a2_m = (fabs.f64 a2)
                  NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                  (FPCore (a1 a2_m th) :precision binary64 (* (/ a2_m (sqrt 2.0)) a2_m))
                  a2_m = fabs(a2);
                  assert(a1 < a2_m && a2_m < th);
                  double code(double a1, double a2_m, double th) {
                  	return (a2_m / sqrt(2.0)) * a2_m;
                  }
                  
                  a2_m = abs(a2)
                  NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                  real(8) function code(a1, a2_m, th)
                      real(8), intent (in) :: a1
                      real(8), intent (in) :: a2_m
                      real(8), intent (in) :: th
                      code = (a2_m / sqrt(2.0d0)) * a2_m
                  end function
                  
                  a2_m = Math.abs(a2);
                  assert a1 < a2_m && a2_m < th;
                  public static double code(double a1, double a2_m, double th) {
                  	return (a2_m / Math.sqrt(2.0)) * a2_m;
                  }
                  
                  a2_m = math.fabs(a2)
                  [a1, a2_m, th] = sort([a1, a2_m, th])
                  def code(a1, a2_m, th):
                  	return (a2_m / math.sqrt(2.0)) * a2_m
                  
                  a2_m = abs(a2)
                  a1, a2_m, th = sort([a1, a2_m, th])
                  function code(a1, a2_m, th)
                  	return Float64(Float64(a2_m / sqrt(2.0)) * a2_m)
                  end
                  
                  a2_m = abs(a2);
                  a1, a2_m, th = num2cell(sort([a1, a2_m, th])){:}
                  function tmp = code(a1, a2_m, th)
                  	tmp = (a2_m / sqrt(2.0)) * a2_m;
                  end
                  
                  a2_m = N[Abs[a2], $MachinePrecision]
                  NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                  code[a1_, a2$95$m_, th_] := N[(N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * a2$95$m), $MachinePrecision]
                  
                  \begin{array}{l}
                  a2_m = \left|a2\right|
                  \\
                  [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\
                  \\
                  \frac{a2\_m}{\sqrt{2}} \cdot a2\_m
                  \end{array}
                  
                  Derivation
                  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

                    \[\leadsto \color{blue}{\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}} \]
                  4. Step-by-step derivation
                    1. unpow2N/A

                      \[\leadsto \frac{\color{blue}{a1 \cdot a1}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}} \]
                    2. associate-*l/N/A

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

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

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

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

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

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

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

                      \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \color{blue}{\frac{a2}{\sqrt{2}}} \cdot a2\right) \]
                    10. lower-sqrt.f6463.8

                      \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \frac{a2}{\color{blue}{\sqrt{2}}} \cdot a2\right) \]
                  5. Applied rewrites63.8%

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

                    \[\leadsto \frac{{a2}^{2}}{\color{blue}{\sqrt{2}}} \]
                  7. Step-by-step derivation
                    1. Applied rewrites42.4%

                      \[\leadsto a2 \cdot \color{blue}{\frac{a2}{\sqrt{2}}} \]
                    2. Final simplification42.4%

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

                    Alternative 9: 27.6% accurate, 9.9× speedup?

                    \[\begin{array}{l} a2_m = \left|a2\right| \\ [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\ \\ \frac{a1}{\sqrt{2}} \cdot a1 \end{array} \]
                    a2_m = (fabs.f64 a2)
                    NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                    (FPCore (a1 a2_m th) :precision binary64 (* (/ a1 (sqrt 2.0)) a1))
                    a2_m = fabs(a2);
                    assert(a1 < a2_m && a2_m < th);
                    double code(double a1, double a2_m, double th) {
                    	return (a1 / sqrt(2.0)) * a1;
                    }
                    
                    a2_m = abs(a2)
                    NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                    real(8) function code(a1, a2_m, th)
                        real(8), intent (in) :: a1
                        real(8), intent (in) :: a2_m
                        real(8), intent (in) :: th
                        code = (a1 / sqrt(2.0d0)) * a1
                    end function
                    
                    a2_m = Math.abs(a2);
                    assert a1 < a2_m && a2_m < th;
                    public static double code(double a1, double a2_m, double th) {
                    	return (a1 / Math.sqrt(2.0)) * a1;
                    }
                    
                    a2_m = math.fabs(a2)
                    [a1, a2_m, th] = sort([a1, a2_m, th])
                    def code(a1, a2_m, th):
                    	return (a1 / math.sqrt(2.0)) * a1
                    
                    a2_m = abs(a2)
                    a1, a2_m, th = sort([a1, a2_m, th])
                    function code(a1, a2_m, th)
                    	return Float64(Float64(a1 / sqrt(2.0)) * a1)
                    end
                    
                    a2_m = abs(a2);
                    a1, a2_m, th = num2cell(sort([a1, a2_m, th])){:}
                    function tmp = code(a1, a2_m, th)
                    	tmp = (a1 / sqrt(2.0)) * a1;
                    end
                    
                    a2_m = N[Abs[a2], $MachinePrecision]
                    NOTE: a1, a2_m, and th should be sorted in increasing order before calling this function.
                    code[a1_, a2$95$m_, th_] := N[(N[(a1 / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * a1), $MachinePrecision]
                    
                    \begin{array}{l}
                    a2_m = \left|a2\right|
                    \\
                    [a1, a2_m, th] = \mathsf{sort}([a1, a2_m, th])\\
                    \\
                    \frac{a1}{\sqrt{2}} \cdot a1
                    \end{array}
                    
                    Derivation
                    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

                      \[\leadsto \color{blue}{\frac{{a1}^{2}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}}} \]
                    4. Step-by-step derivation
                      1. unpow2N/A

                        \[\leadsto \frac{\color{blue}{a1 \cdot a1}}{\sqrt{2}} + \frac{{a2}^{2}}{\sqrt{2}} \]
                      2. associate-*l/N/A

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

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

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

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

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

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

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

                        \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \color{blue}{\frac{a2}{\sqrt{2}}} \cdot a2\right) \]
                      10. lower-sqrt.f6463.8

                        \[\leadsto \mathsf{fma}\left(\frac{a1}{\sqrt{2}}, a1, \frac{a2}{\color{blue}{\sqrt{2}}} \cdot a2\right) \]
                    5. Applied rewrites63.8%

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

                      \[\leadsto \frac{{a1}^{2}}{\color{blue}{\sqrt{2}}} \]
                    7. Step-by-step derivation
                      1. Applied rewrites37.0%

                        \[\leadsto a1 \cdot \color{blue}{\frac{a1}{\sqrt{2}}} \]
                      2. Final simplification37.0%

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

                      Reproduce

                      ?
                      herbie shell --seed 2024268 
                      (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))))