Migdal et al, Equation (64)

Percentage Accurate: 99.6% → 99.1%
Time: 7.7s
Alternatives: 6
Speedup: N/A×

Specification

?
\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{\cos th}{\sqrt{2}}\\ t\_1 \cdot \left(a1 \cdot a1\right) + t\_1 \cdot \left(a2 \cdot a2\right) \end{array} \end{array} \]
(FPCore (a1 a2 th)
 :precision binary64
 (let* ((t_1 (/ (cos th) (sqrt 2.0))))
   (+ (* t_1 (* a1 a1)) (* t_1 (* a2 a2)))))
double code(double a1, double a2, double th) {
	double t_1 = cos(th) / sqrt(2.0);
	return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
}
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 6 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: 99.1% accurate, 2.1× speedup?

\[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \cos th \cdot \left(\sqrt{0.5} \cdot \left(a2\_m \cdot a2\_m\right)\right) \end{array} \]
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
 (* (cos th) (* (sqrt 0.5) (* a2_m 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 cos(th) * (sqrt(0.5) * (a2_m * a2_m));
}
a2_m = abs(a2)
a1_m = abs(a1)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
real(8) function code(a1_m, a2_m, th)
    real(8), intent (in) :: a1_m
    real(8), intent (in) :: a2_m
    real(8), intent (in) :: th
    code = cos(th) * (sqrt(0.5d0) * (a2_m * 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 Math.cos(th) * (Math.sqrt(0.5) * (a2_m * 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 math.cos(th) * (math.sqrt(0.5) * (a2_m * 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(cos(th) * Float64(sqrt(0.5) * Float64(a2_m * 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 = cos(th) * (sqrt(0.5) * (a2_m * 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[Cos[th], $MachinePrecision] * N[(N[Sqrt[0.5], $MachinePrecision] * N[(a2$95$m * a2$95$m), $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])\\
\\
\cos th \cdot \left(\sqrt{0.5} \cdot \left(a2\_m \cdot a2\_m\right)\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. 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. clear-numN/A

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

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

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

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

      \[\leadsto \frac{1}{\color{blue}{\sqrt{2}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
    11. pow1/2N/A

      \[\leadsto \frac{1}{\color{blue}{{2}^{\frac{1}{2}}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
    12. pow-flipN/A

      \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
    13. lower-pow.f64N/A

      \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
    14. metadata-evalN/A

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

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

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

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

      \[\leadsto {2}^{\frac{-1}{2}} \cdot \left(\left(\color{blue}{a2 \cdot a2} + a1 \cdot a1\right) \cdot \cos th\right) \]
    19. lower-fma.f6499.7

      \[\leadsto {2}^{-0.5} \cdot \left(\color{blue}{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)} \cdot \cos th\right) \]
  4. Applied rewrites99.7%

    \[\leadsto \color{blue}{{2}^{-0.5} \cdot \left(\mathsf{fma}\left(a2, a2, a1 \cdot a1\right) \cdot \cos th\right)} \]
  5. Taylor expanded in a1 around 0

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

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

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

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

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

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

      \[\leadsto \color{blue}{\left(\left({a1}^{2} + {a2}^{2}\right) \cdot \sqrt{\frac{1}{2}}\right)} \cdot \cos th \]
    7. unpow2N/A

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

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

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

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

      \[\leadsto \left(\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \cos th \]
    12. lower-cos.f6499.7

      \[\leadsto \left(\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \sqrt{0.5}\right) \cdot \color{blue}{\cos th} \]
  7. Applied rewrites99.7%

    \[\leadsto \color{blue}{\left(\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \sqrt{0.5}\right) \cdot \cos th} \]
  8. Taylor expanded in a1 around 0

    \[\leadsto \left({a2}^{2} \cdot \sqrt{\frac{1}{2}}\right) \cdot \cos th \]
  9. Step-by-step derivation
    1. Applied rewrites58.1%

      \[\leadsto \left(\left(a2 \cdot a2\right) \cdot \sqrt{0.5}\right) \cdot \cos th \]
    2. Final simplification58.1%

      \[\leadsto \cos th \cdot \left(\sqrt{0.5} \cdot \left(a2 \cdot a2\right)\right) \]
    3. Add Preprocessing

    Alternative 2: 77.5% accurate, 0.8× speedup?

    \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \begin{array}{l} t_1 := \frac{\cos th}{\sqrt{2}}\\ \mathbf{if}\;t\_1 \cdot \left(a2\_m \cdot a2\_m\right) + \left(a1\_m \cdot a1\_m\right) \cdot t\_1 \leq -1 \cdot 10^{-161}:\\ \;\;\;\;\frac{a2\_m}{\sqrt{2}} \cdot \left(\mathsf{fma}\left(th \cdot th, -0.5, 1\right) \cdot a2\_m\right)\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5} \cdot \left(a2\_m \cdot a2\_m\right)\\ \end{array} \end{array} \]
    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 (* a2_m a2_m)) (* (* a1_m a1_m) t_1)) -1e-161)
         (* (/ a2_m (sqrt 2.0)) (* (fma (* th th) -0.5 1.0) a2_m))
         (* (sqrt 0.5) (* a2_m 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) {
    	double t_1 = cos(th) / sqrt(2.0);
    	double tmp;
    	if (((t_1 * (a2_m * a2_m)) + ((a1_m * a1_m) * t_1)) <= -1e-161) {
    		tmp = (a2_m / sqrt(2.0)) * (fma((th * th), -0.5, 1.0) * a2_m);
    	} else {
    		tmp = sqrt(0.5) * (a2_m * a2_m);
    	}
    	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(a2_m * a2_m)) + Float64(Float64(a1_m * a1_m) * t_1)) <= -1e-161)
    		tmp = Float64(Float64(a2_m / sqrt(2.0)) * Float64(fma(Float64(th * th), -0.5, 1.0) * a2_m));
    	else
    		tmp = Float64(sqrt(0.5) * Float64(a2_m * a2_m));
    	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[(a2$95$m * a2$95$m), $MachinePrecision]), $MachinePrecision] + N[(N[(a1$95$m * a1$95$m), $MachinePrecision] * t$95$1), $MachinePrecision]), $MachinePrecision], -1e-161], N[(N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * N[(N[(N[(th * th), $MachinePrecision] * -0.5 + 1.0), $MachinePrecision] * a2$95$m), $MachinePrecision]), $MachinePrecision], N[(N[Sqrt[0.5], $MachinePrecision] * N[(a2$95$m * a2$95$m), $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(a2\_m \cdot a2\_m\right) + \left(a1\_m \cdot a1\_m\right) \cdot t\_1 \leq -1 \cdot 10^{-161}:\\
    \;\;\;\;\frac{a2\_m}{\sqrt{2}} \cdot \left(\mathsf{fma}\left(th \cdot th, -0.5, 1\right) \cdot a2\_m\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\sqrt{0.5} \cdot \left(a2\_m \cdot 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))) < -1.00000000000000003e-161

      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.f6454.7

          \[\leadsto \left(\cos th \cdot a2\right) \cdot \frac{a2}{\color{blue}{\sqrt{2}}} \]
      5. Applied rewrites54.7%

        \[\leadsto \color{blue}{\left(\cos th \cdot a2\right) \cdot \frac{a2}{\sqrt{2}}} \]
      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 rewrites49.1%

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

        if -1.00000000000000003e-161 < (+.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 99.6%

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

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

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

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

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

            \[\leadsto \frac{1}{\color{blue}{\sqrt{2}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
          11. pow1/2N/A

            \[\leadsto \frac{1}{\color{blue}{{2}^{\frac{1}{2}}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
          12. pow-flipN/A

            \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
          13. lower-pow.f64N/A

            \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
          14. metadata-evalN/A

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

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

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

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

            \[\leadsto {2}^{\frac{-1}{2}} \cdot \left(\left(\color{blue}{a2 \cdot a2} + a1 \cdot a1\right) \cdot \cos th\right) \]
          19. lower-fma.f6499.7

            \[\leadsto {2}^{-0.5} \cdot \left(\color{blue}{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)} \cdot \cos th\right) \]
        4. Applied rewrites99.7%

          \[\leadsto \color{blue}{{2}^{-0.5} \cdot \left(\mathsf{fma}\left(a2, a2, a1 \cdot a1\right) \cdot \cos th\right)} \]
        5. Taylor expanded in th around 0

          \[\leadsto \color{blue}{\sqrt{\frac{1}{2}} \cdot \left({a1}^{2} + {a2}^{2}\right)} \]
        6. Step-by-step derivation
          1. *-commutativeN/A

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

            \[\leadsto \color{blue}{\left({a1}^{2} + {a2}^{2}\right) \cdot \sqrt{\frac{1}{2}}} \]
          3. unpow2N/A

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

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

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

            \[\leadsto \mathsf{fma}\left(a1, a1, \color{blue}{a2 \cdot a2}\right) \cdot \sqrt{\frac{1}{2}} \]
          7. lower-sqrt.f6484.3

            \[\leadsto \mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \color{blue}{\sqrt{0.5}} \]
        7. Applied rewrites84.3%

          \[\leadsto \color{blue}{\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \sqrt{0.5}} \]
        8. Taylor expanded in a1 around 0

          \[\leadsto {a2}^{2} \cdot \sqrt{\color{blue}{\frac{1}{2}}} \]
        9. Step-by-step derivation
          1. Applied rewrites51.4%

            \[\leadsto \left(a2 \cdot a2\right) \cdot \sqrt{\color{blue}{0.5}} \]
        10. Recombined 2 regimes into one program.
        11. Final simplification50.9%

          \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{\cos th}{\sqrt{2}} \cdot \left(a2 \cdot a2\right) + \left(a1 \cdot a1\right) \cdot \frac{\cos th}{\sqrt{2}} \leq -1 \cdot 10^{-161}:\\ \;\;\;\;\frac{a2}{\sqrt{2}} \cdot \left(\mathsf{fma}\left(th \cdot th, -0.5, 1\right) \cdot a2\right)\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5} \cdot \left(a2 \cdot a2\right)\\ \end{array} \]
        12. Add Preprocessing

        Alternative 3: 99.1% accurate, 2.1× speedup?

        \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \left(\left(\sqrt{0.5} \cdot a2\_m\right) \cdot a2\_m\right) \cdot \cos th \end{array} \]
        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
         (* (* (* (sqrt 0.5) a2_m) a2_m) (cos th)))
        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 ((sqrt(0.5) * a2_m) * a2_m) * cos(th);
        }
        
        a2_m = abs(a2)
        a1_m = abs(a1)
        NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
        real(8) function code(a1_m, a2_m, th)
            real(8), intent (in) :: a1_m
            real(8), intent (in) :: a2_m
            real(8), intent (in) :: th
            code = ((sqrt(0.5d0) * a2_m) * a2_m) * cos(th)
        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.sqrt(0.5) * a2_m) * a2_m) * Math.cos(th);
        }
        
        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.sqrt(0.5) * a2_m) * a2_m) * math.cos(th)
        
        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(sqrt(0.5) * a2_m) * a2_m) * cos(th))
        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 = ((sqrt(0.5) * a2_m) * a2_m) * cos(th);
        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[Sqrt[0.5], $MachinePrecision] * a2$95$m), $MachinePrecision] * a2$95$m), $MachinePrecision] * N[Cos[th], $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(\left(\sqrt{0.5} \cdot a2\_m\right) \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. 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. clear-numN/A

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

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

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

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

            \[\leadsto \frac{1}{\color{blue}{\sqrt{2}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
          11. pow1/2N/A

            \[\leadsto \frac{1}{\color{blue}{{2}^{\frac{1}{2}}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
          12. pow-flipN/A

            \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
          13. lower-pow.f64N/A

            \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
          14. metadata-evalN/A

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

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

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

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

            \[\leadsto {2}^{\frac{-1}{2}} \cdot \left(\left(\color{blue}{a2 \cdot a2} + a1 \cdot a1\right) \cdot \cos th\right) \]
          19. lower-fma.f6499.7

            \[\leadsto {2}^{-0.5} \cdot \left(\color{blue}{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)} \cdot \cos th\right) \]
        4. Applied rewrites99.7%

          \[\leadsto \color{blue}{{2}^{-0.5} \cdot \left(\mathsf{fma}\left(a2, a2, a1 \cdot a1\right) \cdot \cos th\right)} \]
        5. Taylor expanded in a1 around 0

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

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

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

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

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

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

            \[\leadsto \color{blue}{\left(\left({a1}^{2} + {a2}^{2}\right) \cdot \sqrt{\frac{1}{2}}\right)} \cdot \cos th \]
          7. unpow2N/A

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

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

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

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

            \[\leadsto \left(\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \color{blue}{\sqrt{\frac{1}{2}}}\right) \cdot \cos th \]
          12. lower-cos.f6499.7

            \[\leadsto \left(\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \sqrt{0.5}\right) \cdot \color{blue}{\cos th} \]
        7. Applied rewrites99.7%

          \[\leadsto \color{blue}{\left(\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \sqrt{0.5}\right) \cdot \cos th} \]
        8. Taylor expanded in a1 around 0

          \[\leadsto \left({a2}^{2} \cdot \sqrt{\frac{1}{2}}\right) \cdot \cos \color{blue}{th} \]
        9. Step-by-step derivation
          1. Applied rewrites58.1%

            \[\leadsto \left(\left(\sqrt{0.5} \cdot a2\right) \cdot a2\right) \cdot \cos \color{blue}{th} \]
          2. Add Preprocessing

          Alternative 4: 66.3% accurate, 12.7× speedup?

          \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \sqrt{0.5} \cdot \left(a2\_m \cdot a2\_m\right) \end{array} \]
          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 (* (sqrt 0.5) (* a2_m 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 sqrt(0.5) * (a2_m * a2_m);
          }
          
          a2_m = abs(a2)
          a1_m = abs(a1)
          NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
          real(8) function code(a1_m, a2_m, th)
              real(8), intent (in) :: a1_m
              real(8), intent (in) :: a2_m
              real(8), intent (in) :: th
              code = sqrt(0.5d0) * (a2_m * 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 Math.sqrt(0.5) * (a2_m * 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 math.sqrt(0.5) * (a2_m * 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(sqrt(0.5) * Float64(a2_m * 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 = sqrt(0.5) * (a2_m * 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[Sqrt[0.5], $MachinePrecision] * N[(a2$95$m * a2$95$m), $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])\\
          \\
          \sqrt{0.5} \cdot \left(a2\_m \cdot a2\_m\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. 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. clear-numN/A

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

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

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

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

              \[\leadsto \frac{1}{\color{blue}{\sqrt{2}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
            11. pow1/2N/A

              \[\leadsto \frac{1}{\color{blue}{{2}^{\frac{1}{2}}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
            12. pow-flipN/A

              \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
            13. lower-pow.f64N/A

              \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
            14. metadata-evalN/A

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

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

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

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

              \[\leadsto {2}^{\frac{-1}{2}} \cdot \left(\left(\color{blue}{a2 \cdot a2} + a1 \cdot a1\right) \cdot \cos th\right) \]
            19. lower-fma.f6499.7

              \[\leadsto {2}^{-0.5} \cdot \left(\color{blue}{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)} \cdot \cos th\right) \]
          4. Applied rewrites99.7%

            \[\leadsto \color{blue}{{2}^{-0.5} \cdot \left(\mathsf{fma}\left(a2, a2, a1 \cdot a1\right) \cdot \cos th\right)} \]
          5. Taylor expanded in th around 0

            \[\leadsto \color{blue}{\sqrt{\frac{1}{2}} \cdot \left({a1}^{2} + {a2}^{2}\right)} \]
          6. Step-by-step derivation
            1. *-commutativeN/A

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

              \[\leadsto \color{blue}{\left({a1}^{2} + {a2}^{2}\right) \cdot \sqrt{\frac{1}{2}}} \]
            3. unpow2N/A

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

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

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

              \[\leadsto \mathsf{fma}\left(a1, a1, \color{blue}{a2 \cdot a2}\right) \cdot \sqrt{\frac{1}{2}} \]
            7. lower-sqrt.f6466.0

              \[\leadsto \mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \color{blue}{\sqrt{0.5}} \]
          7. Applied rewrites66.0%

            \[\leadsto \color{blue}{\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \sqrt{0.5}} \]
          8. Taylor expanded in a1 around 0

            \[\leadsto {a2}^{2} \cdot \sqrt{\color{blue}{\frac{1}{2}}} \]
          9. Step-by-step derivation
            1. Applied rewrites40.4%

              \[\leadsto \left(a2 \cdot a2\right) \cdot \sqrt{\color{blue}{0.5}} \]
            2. Final simplification40.4%

              \[\leadsto \sqrt{0.5} \cdot \left(a2 \cdot a2\right) \]
            3. Add Preprocessing

            Alternative 5: 66.4% accurate, 12.7× speedup?

            \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \left(\sqrt{0.5} \cdot a2\_m\right) \cdot a2\_m \end{array} \]
            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 (* (* (sqrt 0.5) a2_m) 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 (sqrt(0.5) * a2_m) * a2_m;
            }
            
            a2_m = abs(a2)
            a1_m = abs(a1)
            NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
            real(8) function code(a1_m, a2_m, th)
                real(8), intent (in) :: a1_m
                real(8), intent (in) :: a2_m
                real(8), intent (in) :: th
                code = (sqrt(0.5d0) * a2_m) * 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 (Math.sqrt(0.5) * a2_m) * 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 (math.sqrt(0.5) * a2_m) * 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(sqrt(0.5) * a2_m) * 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 = (sqrt(0.5) * a2_m) * 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[Sqrt[0.5], $MachinePrecision] * a2$95$m), $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(\sqrt{0.5} \cdot a2\_m\right) \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. 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. clear-numN/A

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

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

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

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

                \[\leadsto \frac{1}{\color{blue}{\sqrt{2}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
              11. pow1/2N/A

                \[\leadsto \frac{1}{\color{blue}{{2}^{\frac{1}{2}}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
              12. pow-flipN/A

                \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
              13. lower-pow.f64N/A

                \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
              14. metadata-evalN/A

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

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

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

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

                \[\leadsto {2}^{\frac{-1}{2}} \cdot \left(\left(\color{blue}{a2 \cdot a2} + a1 \cdot a1\right) \cdot \cos th\right) \]
              19. lower-fma.f6499.7

                \[\leadsto {2}^{-0.5} \cdot \left(\color{blue}{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)} \cdot \cos th\right) \]
            4. Applied rewrites99.7%

              \[\leadsto \color{blue}{{2}^{-0.5} \cdot \left(\mathsf{fma}\left(a2, a2, a1 \cdot a1\right) \cdot \cos th\right)} \]
            5. Taylor expanded in th around 0

              \[\leadsto \color{blue}{\sqrt{\frac{1}{2}} \cdot \left({a1}^{2} + {a2}^{2}\right)} \]
            6. Step-by-step derivation
              1. *-commutativeN/A

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

                \[\leadsto \color{blue}{\left({a1}^{2} + {a2}^{2}\right) \cdot \sqrt{\frac{1}{2}}} \]
              3. unpow2N/A

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

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

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

                \[\leadsto \mathsf{fma}\left(a1, a1, \color{blue}{a2 \cdot a2}\right) \cdot \sqrt{\frac{1}{2}} \]
              7. lower-sqrt.f6466.0

                \[\leadsto \mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \color{blue}{\sqrt{0.5}} \]
            7. Applied rewrites66.0%

              \[\leadsto \color{blue}{\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \sqrt{0.5}} \]
            8. Taylor expanded in a1 around 0

              \[\leadsto {a2}^{2} \cdot \color{blue}{\sqrt{\frac{1}{2}}} \]
            9. Step-by-step derivation
              1. Applied rewrites40.4%

                \[\leadsto \left(\sqrt{0.5} \cdot a2\right) \cdot \color{blue}{a2} \]
              2. Add Preprocessing

              Alternative 6: 14.0% accurate, 12.7× speedup?

              \[\begin{array}{l} a2_m = \left|a2\right| \\ a1_m = \left|a1\right| \\ [a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\ \\ \left(\sqrt{0.5} \cdot a1\_m\right) \cdot a1\_m \end{array} \]
              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 (* (* (sqrt 0.5) a1_m) a1_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 (sqrt(0.5) * a1_m) * a1_m;
              }
              
              a2_m = abs(a2)
              a1_m = abs(a1)
              NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
              real(8) function code(a1_m, a2_m, th)
                  real(8), intent (in) :: a1_m
                  real(8), intent (in) :: a2_m
                  real(8), intent (in) :: th
                  code = (sqrt(0.5d0) * a1_m) * a1_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 (Math.sqrt(0.5) * a1_m) * a1_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 (math.sqrt(0.5) * a1_m) * a1_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(sqrt(0.5) * a1_m) * a1_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 = (sqrt(0.5) * a1_m) * a1_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[Sqrt[0.5], $MachinePrecision] * a1$95$m), $MachinePrecision] * a1$95$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(\sqrt{0.5} \cdot a1\_m\right) \cdot a1\_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. 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. clear-numN/A

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

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

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

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

                  \[\leadsto \frac{1}{\color{blue}{\sqrt{2}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
                11. pow1/2N/A

                  \[\leadsto \frac{1}{\color{blue}{{2}^{\frac{1}{2}}}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
                12. pow-flipN/A

                  \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
                13. lower-pow.f64N/A

                  \[\leadsto \color{blue}{{2}^{\left(\mathsf{neg}\left(\frac{1}{2}\right)\right)}} \cdot \left(\cos th \cdot \left(a1 \cdot a1 + a2 \cdot a2\right)\right) \]
                14. metadata-evalN/A

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

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

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

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

                  \[\leadsto {2}^{\frac{-1}{2}} \cdot \left(\left(\color{blue}{a2 \cdot a2} + a1 \cdot a1\right) \cdot \cos th\right) \]
                19. lower-fma.f6499.7

                  \[\leadsto {2}^{-0.5} \cdot \left(\color{blue}{\mathsf{fma}\left(a2, a2, a1 \cdot a1\right)} \cdot \cos th\right) \]
              4. Applied rewrites99.7%

                \[\leadsto \color{blue}{{2}^{-0.5} \cdot \left(\mathsf{fma}\left(a2, a2, a1 \cdot a1\right) \cdot \cos th\right)} \]
              5. Taylor expanded in th around 0

                \[\leadsto \color{blue}{\sqrt{\frac{1}{2}} \cdot \left({a1}^{2} + {a2}^{2}\right)} \]
              6. Step-by-step derivation
                1. *-commutativeN/A

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

                  \[\leadsto \color{blue}{\left({a1}^{2} + {a2}^{2}\right) \cdot \sqrt{\frac{1}{2}}} \]
                3. unpow2N/A

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

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

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

                  \[\leadsto \mathsf{fma}\left(a1, a1, \color{blue}{a2 \cdot a2}\right) \cdot \sqrt{\frac{1}{2}} \]
                7. lower-sqrt.f6466.0

                  \[\leadsto \mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \color{blue}{\sqrt{0.5}} \]
              7. Applied rewrites66.0%

                \[\leadsto \color{blue}{\mathsf{fma}\left(a1, a1, a2 \cdot a2\right) \cdot \sqrt{0.5}} \]
              8. Taylor expanded in a1 around inf

                \[\leadsto {a1}^{2} \cdot \color{blue}{\sqrt{\frac{1}{2}}} \]
              9. Step-by-step derivation
                1. Applied rewrites39.5%

                  \[\leadsto \left(\sqrt{0.5} \cdot a1\right) \cdot \color{blue}{a1} \]
                2. Add Preprocessing

                Reproduce

                ?
                herbie shell --seed 2024243 
                (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))))