Diagrams.TwoD.Apollonian:initialConfig from diagrams-contrib-1.3.0.5, A

Percentage Accurate: 69.1% → 93.9%
Time: 5.5s
Alternatives: 6
Speedup: 0.6×

Specification

?
\[\begin{array}{l} \\ \frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (/ (- (+ (* x x) (* y y)) (* z z)) (* y 2.0)))
double code(double x, double y, double z) {
	return (((x * x) + (y * y)) - (z * z)) / (y * 2.0);
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = (((x * x) + (y * y)) - (z * z)) / (y * 2.0d0)
end function
public static double code(double x, double y, double z) {
	return (((x * x) + (y * y)) - (z * z)) / (y * 2.0);
}
def code(x, y, z):
	return (((x * x) + (y * y)) - (z * z)) / (y * 2.0)
function code(x, y, z)
	return Float64(Float64(Float64(Float64(x * x) + Float64(y * y)) - Float64(z * z)) / Float64(y * 2.0))
end
function tmp = code(x, y, z)
	tmp = (((x * x) + (y * y)) - (z * z)) / (y * 2.0);
end
code[x_, y_, z_] := N[(N[(N[(N[(x * x), $MachinePrecision] + N[(y * y), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(y * 2.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2}
\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: 69.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (/ (- (+ (* x x) (* y y)) (* z z)) (* y 2.0)))
double code(double x, double y, double z) {
	return (((x * x) + (y * y)) - (z * z)) / (y * 2.0);
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = (((x * x) + (y * y)) - (z * z)) / (y * 2.0d0)
end function
public static double code(double x, double y, double z) {
	return (((x * x) + (y * y)) - (z * z)) / (y * 2.0);
}
def code(x, y, z):
	return (((x * x) + (y * y)) - (z * z)) / (y * 2.0)
function code(x, y, z)
	return Float64(Float64(Float64(Float64(x * x) + Float64(y * y)) - Float64(z * z)) / Float64(y * 2.0))
end
function tmp = code(x, y, z)
	tmp = (((x * x) + (y * y)) - (z * z)) / (y * 2.0);
end
code[x_, y_, z_] := N[(N[(N[(N[(x * x), $MachinePrecision] + N[(y * y), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(y * 2.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2}
\end{array}

Alternative 1: 93.9% accurate, 0.5× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ y\_m = \left|y\right| \\ y\_s = \mathsf{copysign}\left(1, y\right) \\ y\_s \cdot \begin{array}{l} \mathbf{if}\;\frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2} \leq 0:\\ \;\;\;\;\left(\left(z + x\_m\right) \cdot 0.5\right) \cdot \frac{x\_m - z}{y\_m}\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{x\_m}{y\_m}, x\_m, y\_m\right) \cdot 0.5\\ \end{array} \end{array} \]
x_m = (fabs.f64 x)
y\_m = (fabs.f64 y)
y\_s = (copysign.f64 #s(literal 1 binary64) y)
(FPCore (y_s x_m y_m z)
 :precision binary64
 (*
  y_s
  (if (<= (/ (- (+ (* x_m x_m) (* y_m y_m)) (* z z)) (* y_m 2.0)) 0.0)
    (* (* (+ z x_m) 0.5) (/ (- x_m z) y_m))
    (* (fma (/ x_m y_m) x_m y_m) 0.5))))
x_m = fabs(x);
y\_m = fabs(y);
y\_s = copysign(1.0, y);
double code(double y_s, double x_m, double y_m, double z) {
	double tmp;
	if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= 0.0) {
		tmp = ((z + x_m) * 0.5) * ((x_m - z) / y_m);
	} else {
		tmp = fma((x_m / y_m), x_m, y_m) * 0.5;
	}
	return y_s * tmp;
}
x_m = abs(x)
y\_m = abs(y)
y\_s = copysign(1.0, y)
function code(y_s, x_m, y_m, z)
	tmp = 0.0
	if (Float64(Float64(Float64(Float64(x_m * x_m) + Float64(y_m * y_m)) - Float64(z * z)) / Float64(y_m * 2.0)) <= 0.0)
		tmp = Float64(Float64(Float64(z + x_m) * 0.5) * Float64(Float64(x_m - z) / y_m));
	else
		tmp = Float64(fma(Float64(x_m / y_m), x_m, y_m) * 0.5);
	end
	return Float64(y_s * tmp)
end
x_m = N[Abs[x], $MachinePrecision]
y\_m = N[Abs[y], $MachinePrecision]
y\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[y]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[y$95$s_, x$95$m_, y$95$m_, z_] := N[(y$95$s * If[LessEqual[N[(N[(N[(N[(x$95$m * x$95$m), $MachinePrecision] + N[(y$95$m * y$95$m), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(y$95$m * 2.0), $MachinePrecision]), $MachinePrecision], 0.0], N[(N[(N[(z + x$95$m), $MachinePrecision] * 0.5), $MachinePrecision] * N[(N[(x$95$m - z), $MachinePrecision] / y$95$m), $MachinePrecision]), $MachinePrecision], N[(N[(N[(x$95$m / y$95$m), $MachinePrecision] * x$95$m + y$95$m), $MachinePrecision] * 0.5), $MachinePrecision]]), $MachinePrecision]
\begin{array}{l}
x_m = \left|x\right|
\\
y\_m = \left|y\right|
\\
y\_s = \mathsf{copysign}\left(1, y\right)

\\
y\_s \cdot \begin{array}{l}
\mathbf{if}\;\frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2} \leq 0:\\
\;\;\;\;\left(\left(z + x\_m\right) \cdot 0.5\right) \cdot \frac{x\_m - z}{y\_m}\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(\frac{x\_m}{y\_m}, x\_m, y\_m\right) \cdot 0.5\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64))) < 0.0

    1. Initial program 81.0%

      \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
    2. Add Preprocessing
    3. Taylor expanded in y around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{{x}^{2} - {z}^{2}}{y}} \]
    4. Step-by-step derivation
      1. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{\frac{1}{2} \cdot \left({x}^{2} - {z}^{2}\right)}{y}} \]
      2. unpow2N/A

        \[\leadsto \frac{\frac{1}{2} \cdot \left(\color{blue}{x \cdot x} - {z}^{2}\right)}{y} \]
      3. unpow2N/A

        \[\leadsto \frac{\frac{1}{2} \cdot \left(x \cdot x - \color{blue}{z \cdot z}\right)}{y} \]
      4. difference-of-squaresN/A

        \[\leadsto \frac{\frac{1}{2} \cdot \color{blue}{\left(\left(x + z\right) \cdot \left(x - z\right)\right)}}{y} \]
      5. associate-*r*N/A

        \[\leadsto \frac{\color{blue}{\left(\frac{1}{2} \cdot \left(x + z\right)\right) \cdot \left(x - z\right)}}{y} \]
      6. associate-/l*N/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot \left(x + z\right)\right) \cdot \frac{x - z}{y}} \]
      7. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot \left(x + z\right)\right) \cdot \frac{x - z}{y}} \]
      8. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\left(x + z\right) \cdot \frac{1}{2}\right)} \cdot \frac{x - z}{y} \]
      9. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\left(x + z\right) \cdot \frac{1}{2}\right)} \cdot \frac{x - z}{y} \]
      10. +-commutativeN/A

        \[\leadsto \left(\color{blue}{\left(z + x\right)} \cdot \frac{1}{2}\right) \cdot \frac{x - z}{y} \]
      11. lower-+.f64N/A

        \[\leadsto \left(\color{blue}{\left(z + x\right)} \cdot \frac{1}{2}\right) \cdot \frac{x - z}{y} \]
      12. lower-/.f64N/A

        \[\leadsto \left(\left(z + x\right) \cdot \frac{1}{2}\right) \cdot \color{blue}{\frac{x - z}{y}} \]
      13. lower--.f6469.5

        \[\leadsto \left(\left(z + x\right) \cdot 0.5\right) \cdot \frac{\color{blue}{x - z}}{y} \]
    5. Applied rewrites69.5%

      \[\leadsto \color{blue}{\left(\left(z + x\right) \cdot 0.5\right) \cdot \frac{x - z}{y}} \]

    if 0.0 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64)))

    1. Initial program 57.7%

      \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
    2. Add Preprocessing
    3. Taylor expanded in z around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{{x}^{2} + {y}^{2}}{y}} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\frac{{x}^{2} + {y}^{2}}{y} \cdot \frac{1}{2}} \]
      2. *-lft-identityN/A

        \[\leadsto \frac{\color{blue}{1 \cdot {x}^{2}} + {y}^{2}}{y} \cdot \frac{1}{2} \]
      3. *-inversesN/A

        \[\leadsto \frac{\color{blue}{\frac{{y}^{2}}{{y}^{2}}} \cdot {x}^{2} + {y}^{2}}{y} \cdot \frac{1}{2} \]
      4. associate-*l/N/A

        \[\leadsto \frac{\color{blue}{\frac{{y}^{2} \cdot {x}^{2}}{{y}^{2}}} + {y}^{2}}{y} \cdot \frac{1}{2} \]
      5. associate-*r/N/A

        \[\leadsto \frac{\color{blue}{{y}^{2} \cdot \frac{{x}^{2}}{{y}^{2}}} + {y}^{2}}{y} \cdot \frac{1}{2} \]
      6. *-rgt-identityN/A

        \[\leadsto \frac{{y}^{2} \cdot \frac{{x}^{2}}{{y}^{2}} + \color{blue}{{y}^{2} \cdot 1}}{y} \cdot \frac{1}{2} \]
      7. distribute-lft-inN/A

        \[\leadsto \frac{\color{blue}{{y}^{2} \cdot \left(\frac{{x}^{2}}{{y}^{2}} + 1\right)}}{y} \cdot \frac{1}{2} \]
      8. +-commutativeN/A

        \[\leadsto \frac{{y}^{2} \cdot \color{blue}{\left(1 + \frac{{x}^{2}}{{y}^{2}}\right)}}{y} \cdot \frac{1}{2} \]
      9. associate-*l/N/A

        \[\leadsto \color{blue}{\left(\frac{{y}^{2}}{y} \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right)} \cdot \frac{1}{2} \]
      10. unpow2N/A

        \[\leadsto \left(\frac{\color{blue}{y \cdot y}}{y} \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right) \cdot \frac{1}{2} \]
      11. associate-/l*N/A

        \[\leadsto \left(\color{blue}{\left(y \cdot \frac{y}{y}\right)} \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right) \cdot \frac{1}{2} \]
      12. *-inversesN/A

        \[\leadsto \left(\left(y \cdot \color{blue}{1}\right) \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right) \cdot \frac{1}{2} \]
      13. *-rgt-identityN/A

        \[\leadsto \left(\color{blue}{y} \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right) \cdot \frac{1}{2} \]
    5. Applied rewrites69.1%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{x}{y}, x, y\right) \cdot 0.5} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 2: 70.4% accurate, 0.4× speedup?

\[\begin{array}{l} x_m = \left|x\right| \\ y\_m = \left|y\right| \\ y\_s = \mathsf{copysign}\left(1, y\right) \\ \begin{array}{l} t_0 := \frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2}\\ y\_s \cdot \begin{array}{l} \mathbf{if}\;t\_0 \leq 0:\\ \;\;\;\;\left(-0.5 \cdot z\right) \cdot \frac{z}{y\_m}\\ \mathbf{elif}\;t\_0 \leq 5 \cdot 10^{+152}:\\ \;\;\;\;0.5 \cdot y\_m\\ \mathbf{else}:\\ \;\;\;\;\frac{x\_m}{y\_m} \cdot \left(x\_m \cdot 0.5\right)\\ \end{array} \end{array} \end{array} \]
x_m = (fabs.f64 x)
y\_m = (fabs.f64 y)
y\_s = (copysign.f64 #s(literal 1 binary64) y)
(FPCore (y_s x_m y_m z)
 :precision binary64
 (let* ((t_0 (/ (- (+ (* x_m x_m) (* y_m y_m)) (* z z)) (* y_m 2.0))))
   (*
    y_s
    (if (<= t_0 0.0)
      (* (* -0.5 z) (/ z y_m))
      (if (<= t_0 5e+152) (* 0.5 y_m) (* (/ x_m y_m) (* x_m 0.5)))))))
x_m = fabs(x);
y\_m = fabs(y);
y\_s = copysign(1.0, y);
double code(double y_s, double x_m, double y_m, double z) {
	double t_0 = (((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0);
	double tmp;
	if (t_0 <= 0.0) {
		tmp = (-0.5 * z) * (z / y_m);
	} else if (t_0 <= 5e+152) {
		tmp = 0.5 * y_m;
	} else {
		tmp = (x_m / y_m) * (x_m * 0.5);
	}
	return y_s * tmp;
}
x_m = abs(x)
y\_m = abs(y)
y\_s = copysign(1.0d0, y)
real(8) function code(y_s, x_m, y_m, z)
    real(8), intent (in) :: y_s
    real(8), intent (in) :: x_m
    real(8), intent (in) :: y_m
    real(8), intent (in) :: z
    real(8) :: t_0
    real(8) :: tmp
    t_0 = (((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0d0)
    if (t_0 <= 0.0d0) then
        tmp = ((-0.5d0) * z) * (z / y_m)
    else if (t_0 <= 5d+152) then
        tmp = 0.5d0 * y_m
    else
        tmp = (x_m / y_m) * (x_m * 0.5d0)
    end if
    code = y_s * tmp
end function
x_m = Math.abs(x);
y\_m = Math.abs(y);
y\_s = Math.copySign(1.0, y);
public static double code(double y_s, double x_m, double y_m, double z) {
	double t_0 = (((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0);
	double tmp;
	if (t_0 <= 0.0) {
		tmp = (-0.5 * z) * (z / y_m);
	} else if (t_0 <= 5e+152) {
		tmp = 0.5 * y_m;
	} else {
		tmp = (x_m / y_m) * (x_m * 0.5);
	}
	return y_s * tmp;
}
x_m = math.fabs(x)
y\_m = math.fabs(y)
y\_s = math.copysign(1.0, y)
def code(y_s, x_m, y_m, z):
	t_0 = (((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)
	tmp = 0
	if t_0 <= 0.0:
		tmp = (-0.5 * z) * (z / y_m)
	elif t_0 <= 5e+152:
		tmp = 0.5 * y_m
	else:
		tmp = (x_m / y_m) * (x_m * 0.5)
	return y_s * tmp
x_m = abs(x)
y\_m = abs(y)
y\_s = copysign(1.0, y)
function code(y_s, x_m, y_m, z)
	t_0 = Float64(Float64(Float64(Float64(x_m * x_m) + Float64(y_m * y_m)) - Float64(z * z)) / Float64(y_m * 2.0))
	tmp = 0.0
	if (t_0 <= 0.0)
		tmp = Float64(Float64(-0.5 * z) * Float64(z / y_m));
	elseif (t_0 <= 5e+152)
		tmp = Float64(0.5 * y_m);
	else
		tmp = Float64(Float64(x_m / y_m) * Float64(x_m * 0.5));
	end
	return Float64(y_s * tmp)
end
x_m = abs(x);
y\_m = abs(y);
y\_s = sign(y) * abs(1.0);
function tmp_2 = code(y_s, x_m, y_m, z)
	t_0 = (((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0);
	tmp = 0.0;
	if (t_0 <= 0.0)
		tmp = (-0.5 * z) * (z / y_m);
	elseif (t_0 <= 5e+152)
		tmp = 0.5 * y_m;
	else
		tmp = (x_m / y_m) * (x_m * 0.5);
	end
	tmp_2 = y_s * tmp;
end
x_m = N[Abs[x], $MachinePrecision]
y\_m = N[Abs[y], $MachinePrecision]
y\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[y]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[y$95$s_, x$95$m_, y$95$m_, z_] := Block[{t$95$0 = N[(N[(N[(N[(x$95$m * x$95$m), $MachinePrecision] + N[(y$95$m * y$95$m), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(y$95$m * 2.0), $MachinePrecision]), $MachinePrecision]}, N[(y$95$s * If[LessEqual[t$95$0, 0.0], N[(N[(-0.5 * z), $MachinePrecision] * N[(z / y$95$m), $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$0, 5e+152], N[(0.5 * y$95$m), $MachinePrecision], N[(N[(x$95$m / y$95$m), $MachinePrecision] * N[(x$95$m * 0.5), $MachinePrecision]), $MachinePrecision]]]), $MachinePrecision]]
\begin{array}{l}
x_m = \left|x\right|
\\
y\_m = \left|y\right|
\\
y\_s = \mathsf{copysign}\left(1, y\right)

\\
\begin{array}{l}
t_0 := \frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2}\\
y\_s \cdot \begin{array}{l}
\mathbf{if}\;t\_0 \leq 0:\\
\;\;\;\;\left(-0.5 \cdot z\right) \cdot \frac{z}{y\_m}\\

\mathbf{elif}\;t\_0 \leq 5 \cdot 10^{+152}:\\
\;\;\;\;0.5 \cdot y\_m\\

\mathbf{else}:\\
\;\;\;\;\frac{x\_m}{y\_m} \cdot \left(x\_m \cdot 0.5\right)\\


\end{array}
\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64))) < 0.0

    1. Initial program 81.0%

      \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
    2. Add Preprocessing
    3. Taylor expanded in z around inf

      \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{{z}^{2}}{y}} \]
    4. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{{z}^{2}}{y}} \]
      2. lower-/.f64N/A

        \[\leadsto \frac{-1}{2} \cdot \color{blue}{\frac{{z}^{2}}{y}} \]
      3. unpow2N/A

        \[\leadsto \frac{-1}{2} \cdot \frac{\color{blue}{z \cdot z}}{y} \]
      4. lower-*.f6433.1

        \[\leadsto -0.5 \cdot \frac{\color{blue}{z \cdot z}}{y} \]
    5. Applied rewrites33.1%

      \[\leadsto \color{blue}{-0.5 \cdot \frac{z \cdot z}{y}} \]
    6. Step-by-step derivation
      1. Applied rewrites36.0%

        \[\leadsto \left(-0.5 \cdot z\right) \cdot \color{blue}{\frac{z}{y}} \]

      if 0.0 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64))) < 5e152

      1. Initial program 99.6%

        \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
      2. Add Preprocessing
      3. Taylor expanded in y around inf

        \[\leadsto \color{blue}{\frac{1}{2} \cdot y} \]
      4. Step-by-step derivation
        1. lower-*.f6464.6

          \[\leadsto \color{blue}{0.5 \cdot y} \]
      5. Applied rewrites64.6%

        \[\leadsto \color{blue}{0.5 \cdot y} \]

      if 5e152 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64)))

      1. Initial program 45.0%

        \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
      2. Add Preprocessing
      3. Taylor expanded in x around inf

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

          \[\leadsto \color{blue}{\frac{{x}^{2}}{y} \cdot \frac{1}{2}} \]
        2. lower-*.f64N/A

          \[\leadsto \color{blue}{\frac{{x}^{2}}{y} \cdot \frac{1}{2}} \]
        3. lower-/.f64N/A

          \[\leadsto \color{blue}{\frac{{x}^{2}}{y}} \cdot \frac{1}{2} \]
        4. unpow2N/A

          \[\leadsto \frac{\color{blue}{x \cdot x}}{y} \cdot \frac{1}{2} \]
        5. lower-*.f6430.1

          \[\leadsto \frac{\color{blue}{x \cdot x}}{y} \cdot 0.5 \]
      5. Applied rewrites30.1%

        \[\leadsto \color{blue}{\frac{x \cdot x}{y} \cdot 0.5} \]
      6. Step-by-step derivation
        1. Applied rewrites34.7%

          \[\leadsto \frac{x}{y} \cdot \color{blue}{\left(x \cdot 0.5\right)} \]
      7. Recombined 3 regimes into one program.
      8. Add Preprocessing

      Alternative 3: 93.6% accurate, 0.6× speedup?

      \[\begin{array}{l} x_m = \left|x\right| \\ y\_m = \left|y\right| \\ y\_s = \mathsf{copysign}\left(1, y\right) \\ y\_s \cdot \begin{array}{l} \mathbf{if}\;\frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2} \leq 0:\\ \;\;\;\;\left(-0.5 \cdot z\right) \cdot \frac{z}{y\_m}\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{x\_m}{y\_m}, x\_m, y\_m\right) \cdot 0.5\\ \end{array} \end{array} \]
      x_m = (fabs.f64 x)
      y\_m = (fabs.f64 y)
      y\_s = (copysign.f64 #s(literal 1 binary64) y)
      (FPCore (y_s x_m y_m z)
       :precision binary64
       (*
        y_s
        (if (<= (/ (- (+ (* x_m x_m) (* y_m y_m)) (* z z)) (* y_m 2.0)) 0.0)
          (* (* -0.5 z) (/ z y_m))
          (* (fma (/ x_m y_m) x_m y_m) 0.5))))
      x_m = fabs(x);
      y\_m = fabs(y);
      y\_s = copysign(1.0, y);
      double code(double y_s, double x_m, double y_m, double z) {
      	double tmp;
      	if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= 0.0) {
      		tmp = (-0.5 * z) * (z / y_m);
      	} else {
      		tmp = fma((x_m / y_m), x_m, y_m) * 0.5;
      	}
      	return y_s * tmp;
      }
      
      x_m = abs(x)
      y\_m = abs(y)
      y\_s = copysign(1.0, y)
      function code(y_s, x_m, y_m, z)
      	tmp = 0.0
      	if (Float64(Float64(Float64(Float64(x_m * x_m) + Float64(y_m * y_m)) - Float64(z * z)) / Float64(y_m * 2.0)) <= 0.0)
      		tmp = Float64(Float64(-0.5 * z) * Float64(z / y_m));
      	else
      		tmp = Float64(fma(Float64(x_m / y_m), x_m, y_m) * 0.5);
      	end
      	return Float64(y_s * tmp)
      end
      
      x_m = N[Abs[x], $MachinePrecision]
      y\_m = N[Abs[y], $MachinePrecision]
      y\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[y]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
      code[y$95$s_, x$95$m_, y$95$m_, z_] := N[(y$95$s * If[LessEqual[N[(N[(N[(N[(x$95$m * x$95$m), $MachinePrecision] + N[(y$95$m * y$95$m), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(y$95$m * 2.0), $MachinePrecision]), $MachinePrecision], 0.0], N[(N[(-0.5 * z), $MachinePrecision] * N[(z / y$95$m), $MachinePrecision]), $MachinePrecision], N[(N[(N[(x$95$m / y$95$m), $MachinePrecision] * x$95$m + y$95$m), $MachinePrecision] * 0.5), $MachinePrecision]]), $MachinePrecision]
      
      \begin{array}{l}
      x_m = \left|x\right|
      \\
      y\_m = \left|y\right|
      \\
      y\_s = \mathsf{copysign}\left(1, y\right)
      
      \\
      y\_s \cdot \begin{array}{l}
      \mathbf{if}\;\frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2} \leq 0:\\
      \;\;\;\;\left(-0.5 \cdot z\right) \cdot \frac{z}{y\_m}\\
      
      \mathbf{else}:\\
      \;\;\;\;\mathsf{fma}\left(\frac{x\_m}{y\_m}, x\_m, y\_m\right) \cdot 0.5\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64))) < 0.0

        1. Initial program 81.0%

          \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
        2. Add Preprocessing
        3. Taylor expanded in z around inf

          \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{{z}^{2}}{y}} \]
        4. Step-by-step derivation
          1. lower-*.f64N/A

            \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{{z}^{2}}{y}} \]
          2. lower-/.f64N/A

            \[\leadsto \frac{-1}{2} \cdot \color{blue}{\frac{{z}^{2}}{y}} \]
          3. unpow2N/A

            \[\leadsto \frac{-1}{2} \cdot \frac{\color{blue}{z \cdot z}}{y} \]
          4. lower-*.f6433.1

            \[\leadsto -0.5 \cdot \frac{\color{blue}{z \cdot z}}{y} \]
        5. Applied rewrites33.1%

          \[\leadsto \color{blue}{-0.5 \cdot \frac{z \cdot z}{y}} \]
        6. Step-by-step derivation
          1. Applied rewrites36.0%

            \[\leadsto \left(-0.5 \cdot z\right) \cdot \color{blue}{\frac{z}{y}} \]

          if 0.0 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64)))

          1. Initial program 57.7%

            \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
          2. Add Preprocessing
          3. Taylor expanded in z around 0

            \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{{x}^{2} + {y}^{2}}{y}} \]
          4. Step-by-step derivation
            1. *-commutativeN/A

              \[\leadsto \color{blue}{\frac{{x}^{2} + {y}^{2}}{y} \cdot \frac{1}{2}} \]
            2. *-lft-identityN/A

              \[\leadsto \frac{\color{blue}{1 \cdot {x}^{2}} + {y}^{2}}{y} \cdot \frac{1}{2} \]
            3. *-inversesN/A

              \[\leadsto \frac{\color{blue}{\frac{{y}^{2}}{{y}^{2}}} \cdot {x}^{2} + {y}^{2}}{y} \cdot \frac{1}{2} \]
            4. associate-*l/N/A

              \[\leadsto \frac{\color{blue}{\frac{{y}^{2} \cdot {x}^{2}}{{y}^{2}}} + {y}^{2}}{y} \cdot \frac{1}{2} \]
            5. associate-*r/N/A

              \[\leadsto \frac{\color{blue}{{y}^{2} \cdot \frac{{x}^{2}}{{y}^{2}}} + {y}^{2}}{y} \cdot \frac{1}{2} \]
            6. *-rgt-identityN/A

              \[\leadsto \frac{{y}^{2} \cdot \frac{{x}^{2}}{{y}^{2}} + \color{blue}{{y}^{2} \cdot 1}}{y} \cdot \frac{1}{2} \]
            7. distribute-lft-inN/A

              \[\leadsto \frac{\color{blue}{{y}^{2} \cdot \left(\frac{{x}^{2}}{{y}^{2}} + 1\right)}}{y} \cdot \frac{1}{2} \]
            8. +-commutativeN/A

              \[\leadsto \frac{{y}^{2} \cdot \color{blue}{\left(1 + \frac{{x}^{2}}{{y}^{2}}\right)}}{y} \cdot \frac{1}{2} \]
            9. associate-*l/N/A

              \[\leadsto \color{blue}{\left(\frac{{y}^{2}}{y} \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right)} \cdot \frac{1}{2} \]
            10. unpow2N/A

              \[\leadsto \left(\frac{\color{blue}{y \cdot y}}{y} \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right) \cdot \frac{1}{2} \]
            11. associate-/l*N/A

              \[\leadsto \left(\color{blue}{\left(y \cdot \frac{y}{y}\right)} \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right) \cdot \frac{1}{2} \]
            12. *-inversesN/A

              \[\leadsto \left(\left(y \cdot \color{blue}{1}\right) \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right) \cdot \frac{1}{2} \]
            13. *-rgt-identityN/A

              \[\leadsto \left(\color{blue}{y} \cdot \left(1 + \frac{{x}^{2}}{{y}^{2}}\right)\right) \cdot \frac{1}{2} \]
          5. Applied rewrites69.1%

            \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{x}{y}, x, y\right) \cdot 0.5} \]
        7. Recombined 2 regimes into one program.
        8. Add Preprocessing

        Alternative 4: 61.8% accurate, 0.6× speedup?

        \[\begin{array}{l} x_m = \left|x\right| \\ y\_m = \left|y\right| \\ y\_s = \mathsf{copysign}\left(1, y\right) \\ y\_s \cdot \begin{array}{l} \mathbf{if}\;\frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2} \leq 0:\\ \;\;\;\;\left(-0.5 \cdot z\right) \cdot \frac{z}{y\_m}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot y\_m\\ \end{array} \end{array} \]
        x_m = (fabs.f64 x)
        y\_m = (fabs.f64 y)
        y\_s = (copysign.f64 #s(literal 1 binary64) y)
        (FPCore (y_s x_m y_m z)
         :precision binary64
         (*
          y_s
          (if (<= (/ (- (+ (* x_m x_m) (* y_m y_m)) (* z z)) (* y_m 2.0)) 0.0)
            (* (* -0.5 z) (/ z y_m))
            (* 0.5 y_m))))
        x_m = fabs(x);
        y\_m = fabs(y);
        y\_s = copysign(1.0, y);
        double code(double y_s, double x_m, double y_m, double z) {
        	double tmp;
        	if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= 0.0) {
        		tmp = (-0.5 * z) * (z / y_m);
        	} else {
        		tmp = 0.5 * y_m;
        	}
        	return y_s * tmp;
        }
        
        x_m = abs(x)
        y\_m = abs(y)
        y\_s = copysign(1.0d0, y)
        real(8) function code(y_s, x_m, y_m, z)
            real(8), intent (in) :: y_s
            real(8), intent (in) :: x_m
            real(8), intent (in) :: y_m
            real(8), intent (in) :: z
            real(8) :: tmp
            if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0d0)) <= 0.0d0) then
                tmp = ((-0.5d0) * z) * (z / y_m)
            else
                tmp = 0.5d0 * y_m
            end if
            code = y_s * tmp
        end function
        
        x_m = Math.abs(x);
        y\_m = Math.abs(y);
        y\_s = Math.copySign(1.0, y);
        public static double code(double y_s, double x_m, double y_m, double z) {
        	double tmp;
        	if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= 0.0) {
        		tmp = (-0.5 * z) * (z / y_m);
        	} else {
        		tmp = 0.5 * y_m;
        	}
        	return y_s * tmp;
        }
        
        x_m = math.fabs(x)
        y\_m = math.fabs(y)
        y\_s = math.copysign(1.0, y)
        def code(y_s, x_m, y_m, z):
        	tmp = 0
        	if ((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= 0.0:
        		tmp = (-0.5 * z) * (z / y_m)
        	else:
        		tmp = 0.5 * y_m
        	return y_s * tmp
        
        x_m = abs(x)
        y\_m = abs(y)
        y\_s = copysign(1.0, y)
        function code(y_s, x_m, y_m, z)
        	tmp = 0.0
        	if (Float64(Float64(Float64(Float64(x_m * x_m) + Float64(y_m * y_m)) - Float64(z * z)) / Float64(y_m * 2.0)) <= 0.0)
        		tmp = Float64(Float64(-0.5 * z) * Float64(z / y_m));
        	else
        		tmp = Float64(0.5 * y_m);
        	end
        	return Float64(y_s * tmp)
        end
        
        x_m = abs(x);
        y\_m = abs(y);
        y\_s = sign(y) * abs(1.0);
        function tmp_2 = code(y_s, x_m, y_m, z)
        	tmp = 0.0;
        	if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= 0.0)
        		tmp = (-0.5 * z) * (z / y_m);
        	else
        		tmp = 0.5 * y_m;
        	end
        	tmp_2 = y_s * tmp;
        end
        
        x_m = N[Abs[x], $MachinePrecision]
        y\_m = N[Abs[y], $MachinePrecision]
        y\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[y]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
        code[y$95$s_, x$95$m_, y$95$m_, z_] := N[(y$95$s * If[LessEqual[N[(N[(N[(N[(x$95$m * x$95$m), $MachinePrecision] + N[(y$95$m * y$95$m), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(y$95$m * 2.0), $MachinePrecision]), $MachinePrecision], 0.0], N[(N[(-0.5 * z), $MachinePrecision] * N[(z / y$95$m), $MachinePrecision]), $MachinePrecision], N[(0.5 * y$95$m), $MachinePrecision]]), $MachinePrecision]
        
        \begin{array}{l}
        x_m = \left|x\right|
        \\
        y\_m = \left|y\right|
        \\
        y\_s = \mathsf{copysign}\left(1, y\right)
        
        \\
        y\_s \cdot \begin{array}{l}
        \mathbf{if}\;\frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2} \leq 0:\\
        \;\;\;\;\left(-0.5 \cdot z\right) \cdot \frac{z}{y\_m}\\
        
        \mathbf{else}:\\
        \;\;\;\;0.5 \cdot y\_m\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64))) < 0.0

          1. Initial program 81.0%

            \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
          2. Add Preprocessing
          3. Taylor expanded in z around inf

            \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{{z}^{2}}{y}} \]
          4. Step-by-step derivation
            1. lower-*.f64N/A

              \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{{z}^{2}}{y}} \]
            2. lower-/.f64N/A

              \[\leadsto \frac{-1}{2} \cdot \color{blue}{\frac{{z}^{2}}{y}} \]
            3. unpow2N/A

              \[\leadsto \frac{-1}{2} \cdot \frac{\color{blue}{z \cdot z}}{y} \]
            4. lower-*.f6433.1

              \[\leadsto -0.5 \cdot \frac{\color{blue}{z \cdot z}}{y} \]
          5. Applied rewrites33.1%

            \[\leadsto \color{blue}{-0.5 \cdot \frac{z \cdot z}{y}} \]
          6. Step-by-step derivation
            1. Applied rewrites36.0%

              \[\leadsto \left(-0.5 \cdot z\right) \cdot \color{blue}{\frac{z}{y}} \]

            if 0.0 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64)))

            1. Initial program 57.7%

              \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
            2. Add Preprocessing
            3. Taylor expanded in y around inf

              \[\leadsto \color{blue}{\frac{1}{2} \cdot y} \]
            4. Step-by-step derivation
              1. lower-*.f6440.0

                \[\leadsto \color{blue}{0.5 \cdot y} \]
            5. Applied rewrites40.0%

              \[\leadsto \color{blue}{0.5 \cdot y} \]
          7. Recombined 2 regimes into one program.
          8. Add Preprocessing

          Alternative 5: 60.6% accurate, 0.6× speedup?

          \[\begin{array}{l} x_m = \left|x\right| \\ y\_m = \left|y\right| \\ y\_s = \mathsf{copysign}\left(1, y\right) \\ y\_s \cdot \begin{array}{l} \mathbf{if}\;\frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2} \leq -2 \cdot 10^{-99}:\\ \;\;\;\;-0.5 \cdot \frac{z \cdot z}{y\_m}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot y\_m\\ \end{array} \end{array} \]
          x_m = (fabs.f64 x)
          y\_m = (fabs.f64 y)
          y\_s = (copysign.f64 #s(literal 1 binary64) y)
          (FPCore (y_s x_m y_m z)
           :precision binary64
           (*
            y_s
            (if (<= (/ (- (+ (* x_m x_m) (* y_m y_m)) (* z z)) (* y_m 2.0)) -2e-99)
              (* -0.5 (/ (* z z) y_m))
              (* 0.5 y_m))))
          x_m = fabs(x);
          y\_m = fabs(y);
          y\_s = copysign(1.0, y);
          double code(double y_s, double x_m, double y_m, double z) {
          	double tmp;
          	if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= -2e-99) {
          		tmp = -0.5 * ((z * z) / y_m);
          	} else {
          		tmp = 0.5 * y_m;
          	}
          	return y_s * tmp;
          }
          
          x_m = abs(x)
          y\_m = abs(y)
          y\_s = copysign(1.0d0, y)
          real(8) function code(y_s, x_m, y_m, z)
              real(8), intent (in) :: y_s
              real(8), intent (in) :: x_m
              real(8), intent (in) :: y_m
              real(8), intent (in) :: z
              real(8) :: tmp
              if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0d0)) <= (-2d-99)) then
                  tmp = (-0.5d0) * ((z * z) / y_m)
              else
                  tmp = 0.5d0 * y_m
              end if
              code = y_s * tmp
          end function
          
          x_m = Math.abs(x);
          y\_m = Math.abs(y);
          y\_s = Math.copySign(1.0, y);
          public static double code(double y_s, double x_m, double y_m, double z) {
          	double tmp;
          	if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= -2e-99) {
          		tmp = -0.5 * ((z * z) / y_m);
          	} else {
          		tmp = 0.5 * y_m;
          	}
          	return y_s * tmp;
          }
          
          x_m = math.fabs(x)
          y\_m = math.fabs(y)
          y\_s = math.copysign(1.0, y)
          def code(y_s, x_m, y_m, z):
          	tmp = 0
          	if ((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= -2e-99:
          		tmp = -0.5 * ((z * z) / y_m)
          	else:
          		tmp = 0.5 * y_m
          	return y_s * tmp
          
          x_m = abs(x)
          y\_m = abs(y)
          y\_s = copysign(1.0, y)
          function code(y_s, x_m, y_m, z)
          	tmp = 0.0
          	if (Float64(Float64(Float64(Float64(x_m * x_m) + Float64(y_m * y_m)) - Float64(z * z)) / Float64(y_m * 2.0)) <= -2e-99)
          		tmp = Float64(-0.5 * Float64(Float64(z * z) / y_m));
          	else
          		tmp = Float64(0.5 * y_m);
          	end
          	return Float64(y_s * tmp)
          end
          
          x_m = abs(x);
          y\_m = abs(y);
          y\_s = sign(y) * abs(1.0);
          function tmp_2 = code(y_s, x_m, y_m, z)
          	tmp = 0.0;
          	if (((((x_m * x_m) + (y_m * y_m)) - (z * z)) / (y_m * 2.0)) <= -2e-99)
          		tmp = -0.5 * ((z * z) / y_m);
          	else
          		tmp = 0.5 * y_m;
          	end
          	tmp_2 = y_s * tmp;
          end
          
          x_m = N[Abs[x], $MachinePrecision]
          y\_m = N[Abs[y], $MachinePrecision]
          y\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[y]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
          code[y$95$s_, x$95$m_, y$95$m_, z_] := N[(y$95$s * If[LessEqual[N[(N[(N[(N[(x$95$m * x$95$m), $MachinePrecision] + N[(y$95$m * y$95$m), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(y$95$m * 2.0), $MachinePrecision]), $MachinePrecision], -2e-99], N[(-0.5 * N[(N[(z * z), $MachinePrecision] / y$95$m), $MachinePrecision]), $MachinePrecision], N[(0.5 * y$95$m), $MachinePrecision]]), $MachinePrecision]
          
          \begin{array}{l}
          x_m = \left|x\right|
          \\
          y\_m = \left|y\right|
          \\
          y\_s = \mathsf{copysign}\left(1, y\right)
          
          \\
          y\_s \cdot \begin{array}{l}
          \mathbf{if}\;\frac{\left(x\_m \cdot x\_m + y\_m \cdot y\_m\right) - z \cdot z}{y\_m \cdot 2} \leq -2 \cdot 10^{-99}:\\
          \;\;\;\;-0.5 \cdot \frac{z \cdot z}{y\_m}\\
          
          \mathbf{else}:\\
          \;\;\;\;0.5 \cdot y\_m\\
          
          
          \end{array}
          \end{array}
          
          Derivation
          1. Split input into 2 regimes
          2. if (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64))) < -2e-99

            1. Initial program 83.3%

              \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
            2. Add Preprocessing
            3. Taylor expanded in z around inf

              \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{{z}^{2}}{y}} \]
            4. Step-by-step derivation
              1. lower-*.f64N/A

                \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{{z}^{2}}{y}} \]
              2. lower-/.f64N/A

                \[\leadsto \frac{-1}{2} \cdot \color{blue}{\frac{{z}^{2}}{y}} \]
              3. unpow2N/A

                \[\leadsto \frac{-1}{2} \cdot \frac{\color{blue}{z \cdot z}}{y} \]
              4. lower-*.f6434.2

                \[\leadsto -0.5 \cdot \frac{\color{blue}{z \cdot z}}{y} \]
            5. Applied rewrites34.2%

              \[\leadsto \color{blue}{-0.5 \cdot \frac{z \cdot z}{y}} \]

            if -2e-99 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64)))

            1. Initial program 56.5%

              \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
            2. Add Preprocessing
            3. Taylor expanded in y around inf

              \[\leadsto \color{blue}{\frac{1}{2} \cdot y} \]
            4. Step-by-step derivation
              1. lower-*.f6440.8

                \[\leadsto \color{blue}{0.5 \cdot y} \]
            5. Applied rewrites40.8%

              \[\leadsto \color{blue}{0.5 \cdot y} \]
          3. Recombined 2 regimes into one program.
          4. Add Preprocessing

          Alternative 6: 34.6% accurate, 6.3× speedup?

          \[\begin{array}{l} x_m = \left|x\right| \\ y\_m = \left|y\right| \\ y\_s = \mathsf{copysign}\left(1, y\right) \\ y\_s \cdot \left(0.5 \cdot y\_m\right) \end{array} \]
          x_m = (fabs.f64 x)
          y\_m = (fabs.f64 y)
          y\_s = (copysign.f64 #s(literal 1 binary64) y)
          (FPCore (y_s x_m y_m z) :precision binary64 (* y_s (* 0.5 y_m)))
          x_m = fabs(x);
          y\_m = fabs(y);
          y\_s = copysign(1.0, y);
          double code(double y_s, double x_m, double y_m, double z) {
          	return y_s * (0.5 * y_m);
          }
          
          x_m = abs(x)
          y\_m = abs(y)
          y\_s = copysign(1.0d0, y)
          real(8) function code(y_s, x_m, y_m, z)
              real(8), intent (in) :: y_s
              real(8), intent (in) :: x_m
              real(8), intent (in) :: y_m
              real(8), intent (in) :: z
              code = y_s * (0.5d0 * y_m)
          end function
          
          x_m = Math.abs(x);
          y\_m = Math.abs(y);
          y\_s = Math.copySign(1.0, y);
          public static double code(double y_s, double x_m, double y_m, double z) {
          	return y_s * (0.5 * y_m);
          }
          
          x_m = math.fabs(x)
          y\_m = math.fabs(y)
          y\_s = math.copysign(1.0, y)
          def code(y_s, x_m, y_m, z):
          	return y_s * (0.5 * y_m)
          
          x_m = abs(x)
          y\_m = abs(y)
          y\_s = copysign(1.0, y)
          function code(y_s, x_m, y_m, z)
          	return Float64(y_s * Float64(0.5 * y_m))
          end
          
          x_m = abs(x);
          y\_m = abs(y);
          y\_s = sign(y) * abs(1.0);
          function tmp = code(y_s, x_m, y_m, z)
          	tmp = y_s * (0.5 * y_m);
          end
          
          x_m = N[Abs[x], $MachinePrecision]
          y\_m = N[Abs[y], $MachinePrecision]
          y\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[y]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
          code[y$95$s_, x$95$m_, y$95$m_, z_] := N[(y$95$s * N[(0.5 * y$95$m), $MachinePrecision]), $MachinePrecision]
          
          \begin{array}{l}
          x_m = \left|x\right|
          \\
          y\_m = \left|y\right|
          \\
          y\_s = \mathsf{copysign}\left(1, y\right)
          
          \\
          y\_s \cdot \left(0.5 \cdot y\_m\right)
          \end{array}
          
          Derivation
          1. Initial program 69.3%

            \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
          2. Add Preprocessing
          3. Taylor expanded in y around inf

            \[\leadsto \color{blue}{\frac{1}{2} \cdot y} \]
          4. Step-by-step derivation
            1. lower-*.f6436.6

              \[\leadsto \color{blue}{0.5 \cdot y} \]
          5. Applied rewrites36.6%

            \[\leadsto \color{blue}{0.5 \cdot y} \]
          6. Add Preprocessing

          Developer Target 1: 99.8% accurate, 1.1× speedup?

          \[\begin{array}{l} \\ y \cdot 0.5 - \left(\frac{0.5}{y} \cdot \left(z + x\right)\right) \cdot \left(z - x\right) \end{array} \]
          (FPCore (x y z)
           :precision binary64
           (- (* y 0.5) (* (* (/ 0.5 y) (+ z x)) (- z x))))
          double code(double x, double y, double z) {
          	return (y * 0.5) - (((0.5 / y) * (z + x)) * (z - x));
          }
          
          real(8) function code(x, y, z)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              real(8), intent (in) :: z
              code = (y * 0.5d0) - (((0.5d0 / y) * (z + x)) * (z - x))
          end function
          
          public static double code(double x, double y, double z) {
          	return (y * 0.5) - (((0.5 / y) * (z + x)) * (z - x));
          }
          
          def code(x, y, z):
          	return (y * 0.5) - (((0.5 / y) * (z + x)) * (z - x))
          
          function code(x, y, z)
          	return Float64(Float64(y * 0.5) - Float64(Float64(Float64(0.5 / y) * Float64(z + x)) * Float64(z - x)))
          end
          
          function tmp = code(x, y, z)
          	tmp = (y * 0.5) - (((0.5 / y) * (z + x)) * (z - x));
          end
          
          code[x_, y_, z_] := N[(N[(y * 0.5), $MachinePrecision] - N[(N[(N[(0.5 / y), $MachinePrecision] * N[(z + x), $MachinePrecision]), $MachinePrecision] * N[(z - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
          
          \begin{array}{l}
          
          \\
          y \cdot 0.5 - \left(\frac{0.5}{y} \cdot \left(z + x\right)\right) \cdot \left(z - x\right)
          \end{array}
          

          Reproduce

          ?
          herbie shell --seed 2024317 
          (FPCore (x y z)
            :name "Diagrams.TwoD.Apollonian:initialConfig from diagrams-contrib-1.3.0.5, A"
            :precision binary64
          
            :alt
            (! :herbie-platform default (- (* y 1/2) (* (* (/ 1/2 y) (+ z x)) (- z x))))
          
            (/ (- (+ (* x x) (* y y)) (* z z)) (* y 2.0)))