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

Percentage Accurate: 69.1% → 95.8%
Time: 7.5s
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: 95.8% accurate, 0.3× speedup?

\[\begin{array}{l} y\_m = \left|y\right| \\ y\_s = \mathsf{copysign}\left(1, y\right) \\ \begin{array}{l} t_0 := 0.5 \cdot \left(y\_m - \frac{z}{y\_m} \cdot z\right)\\ t_1 := \frac{\left(y\_m \cdot y\_m + x \cdot x\right) - z \cdot z}{2 \cdot y\_m}\\ y\_s \cdot \begin{array}{l} \mathbf{if}\;t\_1 \leq 0:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;t\_1 \leq \infty:\\ \;\;\;\;\mathsf{fma}\left(\frac{x}{y\_m}, x, y\_m\right) \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \end{array} \]
y\_m = (fabs.f64 y)
y\_s = (copysign.f64 #s(literal 1 binary64) y)
(FPCore (y_s x y_m z)
 :precision binary64
 (let* ((t_0 (* 0.5 (- y_m (* (/ z y_m) z))))
        (t_1 (/ (- (+ (* y_m y_m) (* x x)) (* z z)) (* 2.0 y_m))))
   (*
    y_s
    (if (<= t_1 0.0)
      t_0
      (if (<= t_1 INFINITY) (* (fma (/ x y_m) x y_m) 0.5) t_0)))))
y\_m = fabs(y);
y\_s = copysign(1.0, y);
double code(double y_s, double x, double y_m, double z) {
	double t_0 = 0.5 * (y_m - ((z / y_m) * z));
	double t_1 = (((y_m * y_m) + (x * x)) - (z * z)) / (2.0 * y_m);
	double tmp;
	if (t_1 <= 0.0) {
		tmp = t_0;
	} else if (t_1 <= ((double) INFINITY)) {
		tmp = fma((x / y_m), x, y_m) * 0.5;
	} else {
		tmp = t_0;
	}
	return y_s * tmp;
}
y\_m = abs(y)
y\_s = copysign(1.0, y)
function code(y_s, x, y_m, z)
	t_0 = Float64(0.5 * Float64(y_m - Float64(Float64(z / y_m) * z)))
	t_1 = Float64(Float64(Float64(Float64(y_m * y_m) + Float64(x * x)) - Float64(z * z)) / Float64(2.0 * y_m))
	tmp = 0.0
	if (t_1 <= 0.0)
		tmp = t_0;
	elseif (t_1 <= Inf)
		tmp = Float64(fma(Float64(x / y_m), x, y_m) * 0.5);
	else
		tmp = t_0;
	end
	return Float64(y_s * tmp)
end
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_, y$95$m_, z_] := Block[{t$95$0 = N[(0.5 * N[(y$95$m - N[(N[(z / y$95$m), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[(N[(y$95$m * y$95$m), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(2.0 * y$95$m), $MachinePrecision]), $MachinePrecision]}, N[(y$95$s * If[LessEqual[t$95$1, 0.0], t$95$0, If[LessEqual[t$95$1, Infinity], N[(N[(N[(x / y$95$m), $MachinePrecision] * x + y$95$m), $MachinePrecision] * 0.5), $MachinePrecision], t$95$0]]), $MachinePrecision]]]
\begin{array}{l}
y\_m = \left|y\right|
\\
y\_s = \mathsf{copysign}\left(1, y\right)

\\
\begin{array}{l}
t_0 := 0.5 \cdot \left(y\_m - \frac{z}{y\_m} \cdot z\right)\\
t_1 := \frac{\left(y\_m \cdot y\_m + x \cdot x\right) - z \cdot z}{2 \cdot y\_m}\\
y\_s \cdot \begin{array}{l}
\mathbf{if}\;t\_1 \leq 0:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;t\_1 \leq \infty:\\
\;\;\;\;\mathsf{fma}\left(\frac{x}{y\_m}, x, y\_m\right) \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\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 or +inf.0 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64)))

    1. Initial program 78.8%

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

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

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

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

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

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

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

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

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

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

        \[\leadsto \color{blue}{\left(\left(\mathsf{neg}\left(\frac{{z}^{2}}{y}\right)\right) + y\right)} \cdot \frac{1}{2} \]
      10. distribute-neg-fracN/A

        \[\leadsto \left(\color{blue}{\frac{\mathsf{neg}\left({z}^{2}\right)}{y}} + y\right) \cdot \frac{1}{2} \]
      11. unpow2N/A

        \[\leadsto \left(\frac{\mathsf{neg}\left(\color{blue}{z \cdot z}\right)}{y} + y\right) \cdot \frac{1}{2} \]
      12. distribute-rgt-neg-inN/A

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

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

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

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\mathsf{neg}\left(z\right)}{y}, z, y\right)} \cdot \frac{1}{2} \]
      16. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\mathsf{neg}\left(z\right)}{y}}, z, y\right) \cdot \frac{1}{2} \]
      17. lower-neg.f6495.0

        \[\leadsto \mathsf{fma}\left(\frac{\color{blue}{-z}}{y}, z, y\right) \cdot 0.5 \]
    5. Applied rewrites95.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{-z}{y}, z, y\right) \cdot 0.5} \]
    6. Step-by-step derivation
      1. Applied rewrites95.0%

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

      if 0.0 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64))) < +inf.0

      1. Initial program 72.5%

        \[\frac{\left(x \cdot x + y \cdot y\right) - z \cdot z}{y \cdot 2} \]
      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 rewrites99.6%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{x}{y}, x, y\right) \cdot 0.5} \]
    7. Recombined 2 regimes into one program.
    8. Final simplification97.5%

      \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{\left(y \cdot y + x \cdot x\right) - z \cdot z}{2 \cdot y} \leq 0:\\ \;\;\;\;0.5 \cdot \left(y - \frac{z}{y} \cdot z\right)\\ \mathbf{elif}\;\frac{\left(y \cdot y + x \cdot x\right) - z \cdot z}{2 \cdot y} \leq \infty:\\ \;\;\;\;\mathsf{fma}\left(\frac{x}{y}, x, y\right) \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \left(y - \frac{z}{y} \cdot z\right)\\ \end{array} \]
    9. Add Preprocessing

    Alternative 2: 72.7% accurate, 0.3× speedup?

    \[\begin{array}{l} y\_m = \left|y\right| \\ y\_s = \mathsf{copysign}\left(1, y\right) \\ \begin{array}{l} t_0 := -0.5 \cdot \left(\frac{z}{y\_m} \cdot z\right)\\ t_1 := \frac{\left(y\_m \cdot y\_m + x \cdot x\right) - z \cdot z}{2 \cdot y\_m}\\ y\_s \cdot \begin{array}{l} \mathbf{if}\;t\_1 \leq 0:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;t\_1 \leq 5 \cdot 10^{+152}:\\ \;\;\;\;0.5 \cdot y\_m\\ \mathbf{elif}\;t\_1 \leq \infty:\\ \;\;\;\;\left(\frac{0.5}{y\_m} \cdot x\right) \cdot x\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \end{array} \]
    y\_m = (fabs.f64 y)
    y\_s = (copysign.f64 #s(literal 1 binary64) y)
    (FPCore (y_s x y_m z)
     :precision binary64
     (let* ((t_0 (* -0.5 (* (/ z y_m) z)))
            (t_1 (/ (- (+ (* y_m y_m) (* x x)) (* z z)) (* 2.0 y_m))))
       (*
        y_s
        (if (<= t_1 0.0)
          t_0
          (if (<= t_1 5e+152)
            (* 0.5 y_m)
            (if (<= t_1 INFINITY) (* (* (/ 0.5 y_m) x) x) t_0))))))
    y\_m = fabs(y);
    y\_s = copysign(1.0, y);
    double code(double y_s, double x, double y_m, double z) {
    	double t_0 = -0.5 * ((z / y_m) * z);
    	double t_1 = (((y_m * y_m) + (x * x)) - (z * z)) / (2.0 * y_m);
    	double tmp;
    	if (t_1 <= 0.0) {
    		tmp = t_0;
    	} else if (t_1 <= 5e+152) {
    		tmp = 0.5 * y_m;
    	} else if (t_1 <= ((double) INFINITY)) {
    		tmp = ((0.5 / y_m) * x) * x;
    	} else {
    		tmp = t_0;
    	}
    	return y_s * tmp;
    }
    
    y\_m = Math.abs(y);
    y\_s = Math.copySign(1.0, y);
    public static double code(double y_s, double x, double y_m, double z) {
    	double t_0 = -0.5 * ((z / y_m) * z);
    	double t_1 = (((y_m * y_m) + (x * x)) - (z * z)) / (2.0 * y_m);
    	double tmp;
    	if (t_1 <= 0.0) {
    		tmp = t_0;
    	} else if (t_1 <= 5e+152) {
    		tmp = 0.5 * y_m;
    	} else if (t_1 <= Double.POSITIVE_INFINITY) {
    		tmp = ((0.5 / y_m) * x) * x;
    	} else {
    		tmp = t_0;
    	}
    	return y_s * tmp;
    }
    
    y\_m = math.fabs(y)
    y\_s = math.copysign(1.0, y)
    def code(y_s, x, y_m, z):
    	t_0 = -0.5 * ((z / y_m) * z)
    	t_1 = (((y_m * y_m) + (x * x)) - (z * z)) / (2.0 * y_m)
    	tmp = 0
    	if t_1 <= 0.0:
    		tmp = t_0
    	elif t_1 <= 5e+152:
    		tmp = 0.5 * y_m
    	elif t_1 <= math.inf:
    		tmp = ((0.5 / y_m) * x) * x
    	else:
    		tmp = t_0
    	return y_s * tmp
    
    y\_m = abs(y)
    y\_s = copysign(1.0, y)
    function code(y_s, x, y_m, z)
    	t_0 = Float64(-0.5 * Float64(Float64(z / y_m) * z))
    	t_1 = Float64(Float64(Float64(Float64(y_m * y_m) + Float64(x * x)) - Float64(z * z)) / Float64(2.0 * y_m))
    	tmp = 0.0
    	if (t_1 <= 0.0)
    		tmp = t_0;
    	elseif (t_1 <= 5e+152)
    		tmp = Float64(0.5 * y_m);
    	elseif (t_1 <= Inf)
    		tmp = Float64(Float64(Float64(0.5 / y_m) * x) * x);
    	else
    		tmp = t_0;
    	end
    	return Float64(y_s * tmp)
    end
    
    y\_m = abs(y);
    y\_s = sign(y) * abs(1.0);
    function tmp_2 = code(y_s, x, y_m, z)
    	t_0 = -0.5 * ((z / y_m) * z);
    	t_1 = (((y_m * y_m) + (x * x)) - (z * z)) / (2.0 * y_m);
    	tmp = 0.0;
    	if (t_1 <= 0.0)
    		tmp = t_0;
    	elseif (t_1 <= 5e+152)
    		tmp = 0.5 * y_m;
    	elseif (t_1 <= Inf)
    		tmp = ((0.5 / y_m) * x) * x;
    	else
    		tmp = t_0;
    	end
    	tmp_2 = y_s * tmp;
    end
    
    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_, y$95$m_, z_] := Block[{t$95$0 = N[(-0.5 * N[(N[(z / y$95$m), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[(N[(y$95$m * y$95$m), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision] - N[(z * z), $MachinePrecision]), $MachinePrecision] / N[(2.0 * y$95$m), $MachinePrecision]), $MachinePrecision]}, N[(y$95$s * If[LessEqual[t$95$1, 0.0], t$95$0, If[LessEqual[t$95$1, 5e+152], N[(0.5 * y$95$m), $MachinePrecision], If[LessEqual[t$95$1, Infinity], N[(N[(N[(0.5 / y$95$m), $MachinePrecision] * x), $MachinePrecision] * x), $MachinePrecision], t$95$0]]]), $MachinePrecision]]]
    
    \begin{array}{l}
    y\_m = \left|y\right|
    \\
    y\_s = \mathsf{copysign}\left(1, y\right)
    
    \\
    \begin{array}{l}
    t_0 := -0.5 \cdot \left(\frac{z}{y\_m} \cdot z\right)\\
    t_1 := \frac{\left(y\_m \cdot y\_m + x \cdot x\right) - z \cdot z}{2 \cdot y\_m}\\
    y\_s \cdot \begin{array}{l}
    \mathbf{if}\;t\_1 \leq 0:\\
    \;\;\;\;t\_0\\
    
    \mathbf{elif}\;t\_1 \leq 5 \cdot 10^{+152}:\\
    \;\;\;\;0.5 \cdot y\_m\\
    
    \mathbf{elif}\;t\_1 \leq \infty:\\
    \;\;\;\;\left(\frac{0.5}{y\_m} \cdot x\right) \cdot x\\
    
    \mathbf{else}:\\
    \;\;\;\;t\_0\\
    
    
    \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 or +inf.0 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64)))

      1. Initial program 65.9%

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

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

          \[\leadsto \color{blue}{y \cdot \frac{1}{2}} \]
        2. lower-*.f648.8

          \[\leadsto \color{blue}{y \cdot 0.5} \]
      5. Applied rewrites8.8%

        \[\leadsto \color{blue}{y \cdot 0.5} \]
      6. Taylor expanded in z around inf

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

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

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

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

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

          \[\leadsto \color{blue}{\left(z \cdot \frac{z}{y}\right)} \cdot \frac{-1}{2} \]
        6. lower-/.f6482.5

          \[\leadsto \left(z \cdot \color{blue}{\frac{z}{y}}\right) \cdot -0.5 \]
      8. Applied rewrites82.5%

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

      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. *-commutativeN/A

          \[\leadsto \color{blue}{y \cdot \frac{1}{2}} \]
        2. lower-*.f6475.6

          \[\leadsto \color{blue}{y \cdot 0.5} \]
      5. Applied rewrites75.6%

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

      if 5e152 < (/.f64 (-.f64 (+.f64 (*.f64 x x) (*.f64 y y)) (*.f64 z z)) (*.f64 y #s(literal 2 binary64))) < +inf.0

      1. Initial program 59.0%

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

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

          \[\leadsto \color{blue}{y \cdot \frac{1}{2}} \]
        2. lower-*.f6440.8

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

        \[\leadsto \color{blue}{y \cdot 0.5} \]
      6. Taylor expanded in x around inf

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

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

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

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

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

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

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

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

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

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

          \[\leadsto \left(\frac{\color{blue}{\frac{1}{2}}}{y} \cdot x\right) \cdot x \]
        11. lower-/.f6461.6

          \[\leadsto \left(\color{blue}{\frac{0.5}{y}} \cdot x\right) \cdot x \]
      8. Applied rewrites61.6%

        \[\leadsto \color{blue}{\left(\frac{0.5}{y} \cdot x\right) \cdot x} \]
    3. Recombined 3 regimes into one program.
    4. Final simplification72.7%

      \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{\left(y \cdot y + x \cdot x\right) - z \cdot z}{2 \cdot y} \leq 0:\\ \;\;\;\;-0.5 \cdot \left(\frac{z}{y} \cdot z\right)\\ \mathbf{elif}\;\frac{\left(y \cdot y + x \cdot x\right) - z \cdot z}{2 \cdot y} \leq 5 \cdot 10^{+152}:\\ \;\;\;\;0.5 \cdot y\\ \mathbf{elif}\;\frac{\left(y \cdot y + x \cdot x\right) - z \cdot z}{2 \cdot y} \leq \infty:\\ \;\;\;\;\left(\frac{0.5}{y} \cdot x\right) \cdot x\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot \left(\frac{z}{y} \cdot z\right)\\ \end{array} \]
    5. Add Preprocessing

    Developer Target 1: 99.9% 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 2024230 
    (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)))