2-ancestry mixing, positive discriminant

Percentage Accurate: 44.6% → 47.2%
Time: 5.8s
Alternatives: 4
Speedup: 1.3×

Specification

?
\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{1}{2 \cdot a}\\ t_1 := \sqrt{g \cdot g - h \cdot h}\\ \sqrt[3]{t_0 \cdot \left(\left(-g\right) + t_1\right)} + \sqrt[3]{t_0 \cdot \left(\left(-g\right) - t_1\right)} \end{array} \end{array} \]
(FPCore (g h a)
 :precision binary64
 (let* ((t_0 (/ 1.0 (* 2.0 a))) (t_1 (sqrt (- (* g g) (* h h)))))
   (+ (cbrt (* t_0 (+ (- g) t_1))) (cbrt (* t_0 (- (- g) t_1))))))
double code(double g, double h, double a) {
	double t_0 = 1.0 / (2.0 * a);
	double t_1 = sqrt(((g * g) - (h * h)));
	return cbrt((t_0 * (-g + t_1))) + cbrt((t_0 * (-g - t_1)));
}
public static double code(double g, double h, double a) {
	double t_0 = 1.0 / (2.0 * a);
	double t_1 = Math.sqrt(((g * g) - (h * h)));
	return Math.cbrt((t_0 * (-g + t_1))) + Math.cbrt((t_0 * (-g - t_1)));
}
function code(g, h, a)
	t_0 = Float64(1.0 / Float64(2.0 * a))
	t_1 = sqrt(Float64(Float64(g * g) - Float64(h * h)))
	return Float64(cbrt(Float64(t_0 * Float64(Float64(-g) + t_1))) + cbrt(Float64(t_0 * Float64(Float64(-g) - t_1))))
end
code[g_, h_, a_] := Block[{t$95$0 = N[(1.0 / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[Sqrt[N[(N[(g * g), $MachinePrecision] - N[(h * h), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, N[(N[Power[N[(t$95$0 * N[((-g) + t$95$1), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision] + N[Power[N[(t$95$0 * N[((-g) - t$95$1), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{1}{2 \cdot a}\\
t_1 := \sqrt{g \cdot g - h \cdot h}\\
\sqrt[3]{t_0 \cdot \left(\left(-g\right) + t_1\right)} + \sqrt[3]{t_0 \cdot \left(\left(-g\right) - t_1\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 4 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: 44.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{1}{2 \cdot a}\\ t_1 := \sqrt{g \cdot g - h \cdot h}\\ \sqrt[3]{t_0 \cdot \left(\left(-g\right) + t_1\right)} + \sqrt[3]{t_0 \cdot \left(\left(-g\right) - t_1\right)} \end{array} \end{array} \]
(FPCore (g h a)
 :precision binary64
 (let* ((t_0 (/ 1.0 (* 2.0 a))) (t_1 (sqrt (- (* g g) (* h h)))))
   (+ (cbrt (* t_0 (+ (- g) t_1))) (cbrt (* t_0 (- (- g) t_1))))))
double code(double g, double h, double a) {
	double t_0 = 1.0 / (2.0 * a);
	double t_1 = sqrt(((g * g) - (h * h)));
	return cbrt((t_0 * (-g + t_1))) + cbrt((t_0 * (-g - t_1)));
}
public static double code(double g, double h, double a) {
	double t_0 = 1.0 / (2.0 * a);
	double t_1 = Math.sqrt(((g * g) - (h * h)));
	return Math.cbrt((t_0 * (-g + t_1))) + Math.cbrt((t_0 * (-g - t_1)));
}
function code(g, h, a)
	t_0 = Float64(1.0 / Float64(2.0 * a))
	t_1 = sqrt(Float64(Float64(g * g) - Float64(h * h)))
	return Float64(cbrt(Float64(t_0 * Float64(Float64(-g) + t_1))) + cbrt(Float64(t_0 * Float64(Float64(-g) - t_1))))
end
code[g_, h_, a_] := Block[{t$95$0 = N[(1.0 / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[Sqrt[N[(N[(g * g), $MachinePrecision] - N[(h * h), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, N[(N[Power[N[(t$95$0 * N[((-g) + t$95$1), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision] + N[Power[N[(t$95$0 * N[((-g) - t$95$1), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{1}{2 \cdot a}\\
t_1 := \sqrt{g \cdot g - h \cdot h}\\
\sqrt[3]{t_0 \cdot \left(\left(-g\right) + t_1\right)} + \sqrt[3]{t_0 \cdot \left(\left(-g\right) - t_1\right)}
\end{array}
\end{array}

Alternative 1: 47.2% accurate, 0.7× speedup?

\[\begin{array}{l} h = |h|\\ \\ \begin{array}{l} t_0 := \sqrt{g \cdot g - h \cdot h}\\ t_1 := \sqrt[3]{\left(g + t_0\right) \cdot \frac{-0.5}{a}}\\ \mathbf{if}\;h \leq 1.55 \cdot 10^{-162}:\\ \;\;\;\;\sqrt[3]{\frac{0.5}{a}} \cdot \sqrt[3]{\mathsf{hypot}\left(g, \sqrt{h \cdot \left(-h\right)}\right) - g} + t_1\\ \mathbf{else}:\\ \;\;\;\;t_1 + \sqrt[3]{\frac{0.5}{a} \cdot \left(t_0 - g\right)}\\ \end{array} \end{array} \]
NOTE: h should be positive before calling this function
(FPCore (g h a)
 :precision binary64
 (let* ((t_0 (sqrt (- (* g g) (* h h)))) (t_1 (cbrt (* (+ g t_0) (/ -0.5 a)))))
   (if (<= h 1.55e-162)
     (+ (* (cbrt (/ 0.5 a)) (cbrt (- (hypot g (sqrt (* h (- h)))) g))) t_1)
     (+ t_1 (cbrt (* (/ 0.5 a) (- t_0 g)))))))
h = abs(h);
double code(double g, double h, double a) {
	double t_0 = sqrt(((g * g) - (h * h)));
	double t_1 = cbrt(((g + t_0) * (-0.5 / a)));
	double tmp;
	if (h <= 1.55e-162) {
		tmp = (cbrt((0.5 / a)) * cbrt((hypot(g, sqrt((h * -h))) - g))) + t_1;
	} else {
		tmp = t_1 + cbrt(((0.5 / a) * (t_0 - g)));
	}
	return tmp;
}
h = Math.abs(h);
public static double code(double g, double h, double a) {
	double t_0 = Math.sqrt(((g * g) - (h * h)));
	double t_1 = Math.cbrt(((g + t_0) * (-0.5 / a)));
	double tmp;
	if (h <= 1.55e-162) {
		tmp = (Math.cbrt((0.5 / a)) * Math.cbrt((Math.hypot(g, Math.sqrt((h * -h))) - g))) + t_1;
	} else {
		tmp = t_1 + Math.cbrt(((0.5 / a) * (t_0 - g)));
	}
	return tmp;
}
h = abs(h)
function code(g, h, a)
	t_0 = sqrt(Float64(Float64(g * g) - Float64(h * h)))
	t_1 = cbrt(Float64(Float64(g + t_0) * Float64(-0.5 / a)))
	tmp = 0.0
	if (h <= 1.55e-162)
		tmp = Float64(Float64(cbrt(Float64(0.5 / a)) * cbrt(Float64(hypot(g, sqrt(Float64(h * Float64(-h)))) - g))) + t_1);
	else
		tmp = Float64(t_1 + cbrt(Float64(Float64(0.5 / a) * Float64(t_0 - g))));
	end
	return tmp
end
NOTE: h should be positive before calling this function
code[g_, h_, a_] := Block[{t$95$0 = N[Sqrt[N[(N[(g * g), $MachinePrecision] - N[(h * h), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[Power[N[(N[(g + t$95$0), $MachinePrecision] * N[(-0.5 / a), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]}, If[LessEqual[h, 1.55e-162], N[(N[(N[Power[N[(0.5 / a), $MachinePrecision], 1/3], $MachinePrecision] * N[Power[N[(N[Sqrt[g ^ 2 + N[Sqrt[N[(h * (-h)), $MachinePrecision]], $MachinePrecision] ^ 2], $MachinePrecision] - g), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] + t$95$1), $MachinePrecision], N[(t$95$1 + N[Power[N[(N[(0.5 / a), $MachinePrecision] * N[(t$95$0 - g), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}
h = |h|\\
\\
\begin{array}{l}
t_0 := \sqrt{g \cdot g - h \cdot h}\\
t_1 := \sqrt[3]{\left(g + t_0\right) \cdot \frac{-0.5}{a}}\\
\mathbf{if}\;h \leq 1.55 \cdot 10^{-162}:\\
\;\;\;\;\sqrt[3]{\frac{0.5}{a}} \cdot \sqrt[3]{\mathsf{hypot}\left(g, \sqrt{h \cdot \left(-h\right)}\right) - g} + t_1\\

\mathbf{else}:\\
\;\;\;\;t_1 + \sqrt[3]{\frac{0.5}{a} \cdot \left(t_0 - g\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if h < 1.5499999999999999e-162

    1. Initial program 43.6%

      \[\sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) + \sqrt{g \cdot g - h \cdot h}\right)} + \sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) - \sqrt{g \cdot g - h \cdot h}\right)} \]
    2. Simplified43.6%

      \[\leadsto \color{blue}{\sqrt[3]{\frac{0.5}{a} \cdot \left(\sqrt{g \cdot g - h \cdot h} - g\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}} \]
    3. Step-by-step derivation
      1. cbrt-prod46.8%

        \[\leadsto \color{blue}{\sqrt[3]{\frac{0.5}{a}} \cdot \sqrt[3]{\sqrt{g \cdot g - h \cdot h} - g}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
      2. sub-neg46.8%

        \[\leadsto \sqrt[3]{\frac{0.5}{a}} \cdot \sqrt[3]{\sqrt{\color{blue}{g \cdot g + \left(-h \cdot h\right)}} - g} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
      3. add-sqr-sqrt33.0%

        \[\leadsto \sqrt[3]{\frac{0.5}{a}} \cdot \sqrt[3]{\sqrt{g \cdot g + \color{blue}{\sqrt{-h \cdot h} \cdot \sqrt{-h \cdot h}}} - g} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
      4. hypot-def35.0%

        \[\leadsto \sqrt[3]{\frac{0.5}{a}} \cdot \sqrt[3]{\color{blue}{\mathsf{hypot}\left(g, \sqrt{-h \cdot h}\right)} - g} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
      5. distribute-rgt-neg-in35.0%

        \[\leadsto \sqrt[3]{\frac{0.5}{a}} \cdot \sqrt[3]{\mathsf{hypot}\left(g, \sqrt{\color{blue}{h \cdot \left(-h\right)}}\right) - g} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
    4. Applied egg-rr35.0%

      \[\leadsto \color{blue}{\sqrt[3]{\frac{0.5}{a}} \cdot \sqrt[3]{\mathsf{hypot}\left(g, \sqrt{h \cdot \left(-h\right)}\right) - g}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]

    if 1.5499999999999999e-162 < h

    1. Initial program 41.1%

      \[\sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) + \sqrt{g \cdot g - h \cdot h}\right)} + \sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) - \sqrt{g \cdot g - h \cdot h}\right)} \]
    2. Simplified41.1%

      \[\leadsto \color{blue}{\sqrt[3]{\frac{0.5}{a} \cdot \left(\sqrt{g \cdot g - h \cdot h} - g\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification36.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;h \leq 1.55 \cdot 10^{-162}:\\ \;\;\;\;\sqrt[3]{\frac{0.5}{a}} \cdot \sqrt[3]{\mathsf{hypot}\left(g, \sqrt{h \cdot \left(-h\right)}\right) - g} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} + \sqrt[3]{\frac{0.5}{a} \cdot \left(\sqrt{g \cdot g - h \cdot h} - g\right)}\\ \end{array} \]

Alternative 2: 45.6% accurate, 1.3× speedup?

\[\begin{array}{l} h = |h|\\ \\ \begin{array}{l} t_0 := \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}\\ \mathbf{if}\;g \leq -1.55 \cdot 10^{-162}:\\ \;\;\;\;t_0 + \sqrt[3]{\frac{0.5}{a} \cdot \left(g \cdot -2\right)}\\ \mathbf{else}:\\ \;\;\;\;t_0 + \sqrt[3]{\frac{0.5}{a} \cdot \left(-0.5 \cdot \frac{h}{\frac{g}{h}}\right)}\\ \end{array} \end{array} \]
NOTE: h should be positive before calling this function
(FPCore (g h a)
 :precision binary64
 (let* ((t_0 (cbrt (* (+ g (sqrt (- (* g g) (* h h)))) (/ -0.5 a)))))
   (if (<= g -1.55e-162)
     (+ t_0 (cbrt (* (/ 0.5 a) (* g -2.0))))
     (+ t_0 (cbrt (* (/ 0.5 a) (* -0.5 (/ h (/ g h)))))))))
h = abs(h);
double code(double g, double h, double a) {
	double t_0 = cbrt(((g + sqrt(((g * g) - (h * h)))) * (-0.5 / a)));
	double tmp;
	if (g <= -1.55e-162) {
		tmp = t_0 + cbrt(((0.5 / a) * (g * -2.0)));
	} else {
		tmp = t_0 + cbrt(((0.5 / a) * (-0.5 * (h / (g / h)))));
	}
	return tmp;
}
h = Math.abs(h);
public static double code(double g, double h, double a) {
	double t_0 = Math.cbrt(((g + Math.sqrt(((g * g) - (h * h)))) * (-0.5 / a)));
	double tmp;
	if (g <= -1.55e-162) {
		tmp = t_0 + Math.cbrt(((0.5 / a) * (g * -2.0)));
	} else {
		tmp = t_0 + Math.cbrt(((0.5 / a) * (-0.5 * (h / (g / h)))));
	}
	return tmp;
}
h = abs(h)
function code(g, h, a)
	t_0 = cbrt(Float64(Float64(g + sqrt(Float64(Float64(g * g) - Float64(h * h)))) * Float64(-0.5 / a)))
	tmp = 0.0
	if (g <= -1.55e-162)
		tmp = Float64(t_0 + cbrt(Float64(Float64(0.5 / a) * Float64(g * -2.0))));
	else
		tmp = Float64(t_0 + cbrt(Float64(Float64(0.5 / a) * Float64(-0.5 * Float64(h / Float64(g / h))))));
	end
	return tmp
end
NOTE: h should be positive before calling this function
code[g_, h_, a_] := Block[{t$95$0 = N[Power[N[(N[(g + N[Sqrt[N[(N[(g * g), $MachinePrecision] - N[(h * h), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(-0.5 / a), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]}, If[LessEqual[g, -1.55e-162], N[(t$95$0 + N[Power[N[(N[(0.5 / a), $MachinePrecision] * N[(g * -2.0), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision], N[(t$95$0 + N[Power[N[(N[(0.5 / a), $MachinePrecision] * N[(-0.5 * N[(h / N[(g / h), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
h = |h|\\
\\
\begin{array}{l}
t_0 := \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}\\
\mathbf{if}\;g \leq -1.55 \cdot 10^{-162}:\\
\;\;\;\;t_0 + \sqrt[3]{\frac{0.5}{a} \cdot \left(g \cdot -2\right)}\\

\mathbf{else}:\\
\;\;\;\;t_0 + \sqrt[3]{\frac{0.5}{a} \cdot \left(-0.5 \cdot \frac{h}{\frac{g}{h}}\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if g < -1.5499999999999999e-162

    1. Initial program 42.4%

      \[\sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) + \sqrt{g \cdot g - h \cdot h}\right)} + \sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) - \sqrt{g \cdot g - h \cdot h}\right)} \]
    2. Simplified42.4%

      \[\leadsto \color{blue}{\sqrt[3]{\frac{0.5}{a} \cdot \left(\sqrt{g \cdot g - h \cdot h} - g\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}} \]
    3. Taylor expanded in g around -inf 42.6%

      \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(-2 \cdot g\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
    4. Step-by-step derivation
      1. *-commutative42.6%

        \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(g \cdot -2\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
    5. Simplified42.6%

      \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(g \cdot -2\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]

    if -1.5499999999999999e-162 < g

    1. Initial program 43.4%

      \[\sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) + \sqrt{g \cdot g - h \cdot h}\right)} + \sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) - \sqrt{g \cdot g - h \cdot h}\right)} \]
    2. Simplified43.4%

      \[\leadsto \color{blue}{\sqrt[3]{\frac{0.5}{a} \cdot \left(\sqrt{g \cdot g - h \cdot h} - g\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}} \]
    3. Taylor expanded in g around inf 46.1%

      \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(-0.5 \cdot \frac{{h}^{2}}{g}\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
    4. Step-by-step derivation
      1. unpow246.1%

        \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \left(-0.5 \cdot \frac{\color{blue}{h \cdot h}}{g}\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
      2. associate-/l*46.4%

        \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \left(-0.5 \cdot \color{blue}{\frac{h}{\frac{g}{h}}}\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
    5. Simplified46.4%

      \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(-0.5 \cdot \frac{h}{\frac{g}{h}}\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification44.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;g \leq -1.55 \cdot 10^{-162}:\\ \;\;\;\;\sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} + \sqrt[3]{\frac{0.5}{a} \cdot \left(g \cdot -2\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} + \sqrt[3]{\frac{0.5}{a} \cdot \left(-0.5 \cdot \frac{h}{\frac{g}{h}}\right)}\\ \end{array} \]

Alternative 3: 45.1% accurate, 1.3× speedup?

\[\begin{array}{l} h = |h|\\ \\ \begin{array}{l} t_0 := \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}\\ \mathbf{if}\;g \leq -1.55 \cdot 10^{-162}:\\ \;\;\;\;t_0 + \sqrt[3]{\frac{0.5}{a} \cdot \left(g \cdot -2\right)}\\ \mathbf{else}:\\ \;\;\;\;t_0 + \sqrt[3]{\frac{0.5}{a} \cdot \left(g - g\right)}\\ \end{array} \end{array} \]
NOTE: h should be positive before calling this function
(FPCore (g h a)
 :precision binary64
 (let* ((t_0 (cbrt (* (+ g (sqrt (- (* g g) (* h h)))) (/ -0.5 a)))))
   (if (<= g -1.55e-162)
     (+ t_0 (cbrt (* (/ 0.5 a) (* g -2.0))))
     (+ t_0 (cbrt (* (/ 0.5 a) (- g g)))))))
h = abs(h);
double code(double g, double h, double a) {
	double t_0 = cbrt(((g + sqrt(((g * g) - (h * h)))) * (-0.5 / a)));
	double tmp;
	if (g <= -1.55e-162) {
		tmp = t_0 + cbrt(((0.5 / a) * (g * -2.0)));
	} else {
		tmp = t_0 + cbrt(((0.5 / a) * (g - g)));
	}
	return tmp;
}
h = Math.abs(h);
public static double code(double g, double h, double a) {
	double t_0 = Math.cbrt(((g + Math.sqrt(((g * g) - (h * h)))) * (-0.5 / a)));
	double tmp;
	if (g <= -1.55e-162) {
		tmp = t_0 + Math.cbrt(((0.5 / a) * (g * -2.0)));
	} else {
		tmp = t_0 + Math.cbrt(((0.5 / a) * (g - g)));
	}
	return tmp;
}
h = abs(h)
function code(g, h, a)
	t_0 = cbrt(Float64(Float64(g + sqrt(Float64(Float64(g * g) - Float64(h * h)))) * Float64(-0.5 / a)))
	tmp = 0.0
	if (g <= -1.55e-162)
		tmp = Float64(t_0 + cbrt(Float64(Float64(0.5 / a) * Float64(g * -2.0))));
	else
		tmp = Float64(t_0 + cbrt(Float64(Float64(0.5 / a) * Float64(g - g))));
	end
	return tmp
end
NOTE: h should be positive before calling this function
code[g_, h_, a_] := Block[{t$95$0 = N[Power[N[(N[(g + N[Sqrt[N[(N[(g * g), $MachinePrecision] - N[(h * h), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(-0.5 / a), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]}, If[LessEqual[g, -1.55e-162], N[(t$95$0 + N[Power[N[(N[(0.5 / a), $MachinePrecision] * N[(g * -2.0), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision], N[(t$95$0 + N[Power[N[(N[(0.5 / a), $MachinePrecision] * N[(g - g), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
h = |h|\\
\\
\begin{array}{l}
t_0 := \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}\\
\mathbf{if}\;g \leq -1.55 \cdot 10^{-162}:\\
\;\;\;\;t_0 + \sqrt[3]{\frac{0.5}{a} \cdot \left(g \cdot -2\right)}\\

\mathbf{else}:\\
\;\;\;\;t_0 + \sqrt[3]{\frac{0.5}{a} \cdot \left(g - g\right)}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if g < -1.5499999999999999e-162

    1. Initial program 42.4%

      \[\sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) + \sqrt{g \cdot g - h \cdot h}\right)} + \sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) - \sqrt{g \cdot g - h \cdot h}\right)} \]
    2. Simplified42.4%

      \[\leadsto \color{blue}{\sqrt[3]{\frac{0.5}{a} \cdot \left(\sqrt{g \cdot g - h \cdot h} - g\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}} \]
    3. Taylor expanded in g around -inf 42.6%

      \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(-2 \cdot g\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
    4. Step-by-step derivation
      1. *-commutative42.6%

        \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(g \cdot -2\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
    5. Simplified42.6%

      \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(g \cdot -2\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]

    if -1.5499999999999999e-162 < g

    1. Initial program 43.4%

      \[\sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) + \sqrt{g \cdot g - h \cdot h}\right)} + \sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) - \sqrt{g \cdot g - h \cdot h}\right)} \]
    2. Simplified43.4%

      \[\leadsto \color{blue}{\sqrt[3]{\frac{0.5}{a} \cdot \left(\sqrt{g \cdot g - h \cdot h} - g\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}} \]
    3. Taylor expanded in g around inf 45.0%

      \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \left(\color{blue}{g} - g\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification43.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;g \leq -1.55 \cdot 10^{-162}:\\ \;\;\;\;\sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} + \sqrt[3]{\frac{0.5}{a} \cdot \left(g \cdot -2\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} + \sqrt[3]{\frac{0.5}{a} \cdot \left(g - g\right)}\\ \end{array} \]

Alternative 4: 28.0% accurate, 1.3× speedup?

\[\begin{array}{l} h = |h|\\ \\ \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} + \sqrt[3]{\frac{0.5}{a} \cdot \left(g \cdot -2\right)} \end{array} \]
NOTE: h should be positive before calling this function
(FPCore (g h a)
 :precision binary64
 (+
  (cbrt (* (+ g (sqrt (- (* g g) (* h h)))) (/ -0.5 a)))
  (cbrt (* (/ 0.5 a) (* g -2.0)))))
h = abs(h);
double code(double g, double h, double a) {
	return cbrt(((g + sqrt(((g * g) - (h * h)))) * (-0.5 / a))) + cbrt(((0.5 / a) * (g * -2.0)));
}
h = Math.abs(h);
public static double code(double g, double h, double a) {
	return Math.cbrt(((g + Math.sqrt(((g * g) - (h * h)))) * (-0.5 / a))) + Math.cbrt(((0.5 / a) * (g * -2.0)));
}
h = abs(h)
function code(g, h, a)
	return Float64(cbrt(Float64(Float64(g + sqrt(Float64(Float64(g * g) - Float64(h * h)))) * Float64(-0.5 / a))) + cbrt(Float64(Float64(0.5 / a) * Float64(g * -2.0))))
end
NOTE: h should be positive before calling this function
code[g_, h_, a_] := N[(N[Power[N[(N[(g + N[Sqrt[N[(N[(g * g), $MachinePrecision] - N[(h * h), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(-0.5 / a), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision] + N[Power[N[(N[(0.5 / a), $MachinePrecision] * N[(g * -2.0), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
h = |h|\\
\\
\sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} + \sqrt[3]{\frac{0.5}{a} \cdot \left(g \cdot -2\right)}
\end{array}
Derivation
  1. Initial program 43.0%

    \[\sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) + \sqrt{g \cdot g - h \cdot h}\right)} + \sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) - \sqrt{g \cdot g - h \cdot h}\right)} \]
  2. Simplified43.0%

    \[\leadsto \color{blue}{\sqrt[3]{\frac{0.5}{a} \cdot \left(\sqrt{g \cdot g - h \cdot h} - g\right)} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}}} \]
  3. Taylor expanded in g around -inf 25.3%

    \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(-2 \cdot g\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
  4. Step-by-step derivation
    1. *-commutative25.3%

      \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(g \cdot -2\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
  5. Simplified25.3%

    \[\leadsto \sqrt[3]{\frac{0.5}{a} \cdot \color{blue}{\left(g \cdot -2\right)}} + \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} \]
  6. Final simplification25.3%

    \[\leadsto \sqrt[3]{\left(g + \sqrt{g \cdot g - h \cdot h}\right) \cdot \frac{-0.5}{a}} + \sqrt[3]{\frac{0.5}{a} \cdot \left(g \cdot -2\right)} \]

Reproduce

?
herbie shell --seed 2023309 
(FPCore (g h a)
  :name "2-ancestry mixing, positive discriminant"
  :precision binary64
  (+ (cbrt (* (/ 1.0 (* 2.0 a)) (+ (- g) (sqrt (- (* g g) (* h h)))))) (cbrt (* (/ 1.0 (* 2.0 a)) (- (- g) (sqrt (- (* g g) (* h h))))))))