
(FPCore (x) :precision binary64 (- (cbrt (+ x 1.0)) (cbrt x)))
double code(double x) {
return cbrt((x + 1.0)) - cbrt(x);
}
public static double code(double x) {
return Math.cbrt((x + 1.0)) - Math.cbrt(x);
}
function code(x) return Float64(cbrt(Float64(x + 1.0)) - cbrt(x)) end
code[x_] := N[(N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision] - N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\sqrt[3]{x + 1} - \sqrt[3]{x}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 10 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (- (cbrt (+ x 1.0)) (cbrt x)))
double code(double x) {
return cbrt((x + 1.0)) - cbrt(x);
}
public static double code(double x) {
return Math.cbrt((x + 1.0)) - Math.cbrt(x);
}
function code(x) return Float64(cbrt(Float64(x + 1.0)) - cbrt(x)) end
code[x_] := N[(N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision] - N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\sqrt[3]{x + 1} - \sqrt[3]{x}
\end{array}
(FPCore (x) :precision binary64 (let* ((t_0 (cbrt (sqrt (+ 1.0 x)))) (t_1 (cbrt (+ 1.0 x)))) (/ 1.0 (fma (cbrt x) (+ (cbrt x) (* t_0 t_0)) (* t_1 t_1)))))
double code(double x) {
double t_0 = cbrt(sqrt((1.0 + x)));
double t_1 = cbrt((1.0 + x));
return 1.0 / fma(cbrt(x), (cbrt(x) + (t_0 * t_0)), (t_1 * t_1));
}
function code(x) t_0 = cbrt(sqrt(Float64(1.0 + x))) t_1 = cbrt(Float64(1.0 + x)) return Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + Float64(t_0 * t_0)), Float64(t_1 * t_1))) end
code[x_] := Block[{t$95$0 = N[Power[N[Sqrt[N[(1.0 + x), $MachinePrecision]], $MachinePrecision], 1/3], $MachinePrecision]}, Block[{t$95$1 = N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]}, N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[(t$95$0 * t$95$0), $MachinePrecision]), $MachinePrecision] + N[(t$95$1 * t$95$1), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{\sqrt{1 + x}}\\
t_1 := \sqrt[3]{1 + x}\\
\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + t\_0 \cdot t\_0, t\_1 \cdot t\_1\right)}
\end{array}
\end{array}
Initial program 7.5%
flip3--7.8%
div-inv7.8%
rem-cube-cbrt7.6%
rem-cube-cbrt10.2%
+-commutative10.2%
distribute-rgt-out10.2%
+-commutative10.2%
fma-define10.2%
add-exp-log10.1%
Applied egg-rr10.1%
associate-*r/10.1%
*-rgt-identity10.1%
+-commutative10.1%
associate--l+93.6%
+-inverses93.6%
metadata-eval93.6%
+-commutative93.6%
exp-prod92.4%
Simplified92.4%
pow-exp93.6%
*-commutative93.6%
log1p-undefine93.6%
+-commutative93.6%
exp-to-pow93.0%
metadata-eval93.0%
pow-prod-up93.0%
pow1/394.5%
pow1/398.6%
Applied egg-rr98.6%
pow1/394.4%
+-commutative94.4%
add-sqr-sqrt94.5%
unpow-prod-down94.5%
Applied egg-rr94.5%
unpow1/395.9%
+-commutative95.9%
unpow1/398.6%
+-commutative98.6%
Simplified98.6%
Final simplification98.6%
(FPCore (x)
:precision binary64
(let* ((t_0 (+ (cbrt x) (cbrt (+ 1.0 x)))))
(if (<= x 1.35e+154)
(/ 1.0 (fma (cbrt x) t_0 (cbrt (pow (+ 1.0 x) 2.0))))
(/ 1.0 (fma (cbrt x) t_0 (exp (* 0.6666666666666666 (log1p x))))))))
double code(double x) {
double t_0 = cbrt(x) + cbrt((1.0 + x));
double tmp;
if (x <= 1.35e+154) {
tmp = 1.0 / fma(cbrt(x), t_0, cbrt(pow((1.0 + x), 2.0)));
} else {
tmp = 1.0 / fma(cbrt(x), t_0, exp((0.6666666666666666 * log1p(x))));
}
return tmp;
}
function code(x) t_0 = Float64(cbrt(x) + cbrt(Float64(1.0 + x))) tmp = 0.0 if (x <= 1.35e+154) tmp = Float64(1.0 / fma(cbrt(x), t_0, cbrt((Float64(1.0 + x) ^ 2.0)))); else tmp = Float64(1.0 / fma(cbrt(x), t_0, exp(Float64(0.6666666666666666 * log1p(x))))); end return tmp end
code[x_] := Block[{t$95$0 = N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[x, 1.35e+154], N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * t$95$0 + N[Power[N[Power[N[(1.0 + x), $MachinePrecision], 2.0], $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * t$95$0 + N[Exp[N[(0.6666666666666666 * N[Log[1 + x], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{x} + \sqrt[3]{1 + x}\\
\mathbf{if}\;x \leq 1.35 \cdot 10^{+154}:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, t\_0, \sqrt[3]{{\left(1 + x\right)}^{2}}\right)}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, t\_0, e^{0.6666666666666666 \cdot \mathsf{log1p}\left(x\right)}\right)}\\
\end{array}
\end{array}
if x < 1.35000000000000003e154Initial program 10.8%
flip3--11.3%
div-inv11.3%
rem-cube-cbrt13.0%
rem-cube-cbrt16.4%
+-commutative16.4%
distribute-rgt-out16.4%
+-commutative16.4%
fma-define16.4%
add-exp-log16.3%
Applied egg-rr16.2%
associate-*r/16.2%
*-rgt-identity16.2%
+-commutative16.2%
associate--l+95.1%
+-inverses95.1%
metadata-eval95.1%
+-commutative95.1%
exp-prod93.9%
Simplified93.9%
pow-exp95.1%
*-commutative95.1%
log1p-undefine95.0%
+-commutative95.0%
exp-to-pow94.7%
metadata-eval94.7%
pow-prod-up94.6%
pow1/396.0%
pow1/398.6%
cbrt-unprod98.9%
pow298.9%
Applied egg-rr98.9%
if 1.35000000000000003e154 < x Initial program 4.8%
flip3--4.8%
div-inv4.8%
rem-cube-cbrt2.9%
rem-cube-cbrt4.8%
+-commutative4.8%
distribute-rgt-out4.8%
+-commutative4.8%
fma-define4.8%
add-exp-log4.8%
Applied egg-rr4.8%
associate-*r/4.8%
*-rgt-identity4.8%
+-commutative4.8%
associate--l+92.3%
+-inverses92.3%
metadata-eval92.3%
+-commutative92.3%
exp-prod91.0%
Simplified91.0%
pow-exp92.3%
Applied egg-rr92.3%
Final simplification95.4%
(FPCore (x) :precision binary64 (let* ((t_0 (cbrt (+ 1.0 x)))) (/ 1.0 (fma (cbrt x) (+ (cbrt x) t_0) (pow t_0 2.0)))))
double code(double x) {
double t_0 = cbrt((1.0 + x));
return 1.0 / fma(cbrt(x), (cbrt(x) + t_0), pow(t_0, 2.0));
}
function code(x) t_0 = cbrt(Float64(1.0 + x)) return Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + t_0), (t_0 ^ 2.0))) end
code[x_] := Block[{t$95$0 = N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]}, N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + t$95$0), $MachinePrecision] + N[Power[t$95$0, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{1 + x}\\
\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + t\_0, {t\_0}^{2}\right)}
\end{array}
\end{array}
Initial program 7.5%
flip3--7.8%
div-inv7.8%
rem-cube-cbrt7.6%
rem-cube-cbrt10.2%
+-commutative10.2%
distribute-rgt-out10.2%
+-commutative10.2%
fma-define10.2%
add-exp-log10.1%
Applied egg-rr10.1%
associate-*r/10.1%
*-rgt-identity10.1%
+-commutative10.1%
associate--l+93.6%
+-inverses93.6%
metadata-eval93.6%
+-commutative93.6%
exp-prod92.4%
Simplified92.4%
pow-exp93.6%
*-commutative93.6%
log1p-undefine93.6%
+-commutative93.6%
exp-to-pow93.0%
metadata-eval93.0%
pow-prod-up93.0%
pow1/394.5%
pow1/398.6%
Applied egg-rr98.6%
pow298.6%
Applied egg-rr98.6%
Final simplification98.6%
(FPCore (x) :precision binary64 (/ 1.0 (fma (cbrt x) (+ (cbrt x) (cbrt (+ 1.0 x))) (exp (* 0.6666666666666666 (log1p x))))))
double code(double x) {
return 1.0 / fma(cbrt(x), (cbrt(x) + cbrt((1.0 + x))), exp((0.6666666666666666 * log1p(x))));
}
function code(x) return Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + cbrt(Float64(1.0 + x))), exp(Float64(0.6666666666666666 * log1p(x))))) end
code[x_] := N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] + N[Exp[N[(0.6666666666666666 * N[Log[1 + x], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + \sqrt[3]{1 + x}, e^{0.6666666666666666 \cdot \mathsf{log1p}\left(x\right)}\right)}
\end{array}
Initial program 7.5%
flip3--7.8%
div-inv7.8%
rem-cube-cbrt7.6%
rem-cube-cbrt10.2%
+-commutative10.2%
distribute-rgt-out10.2%
+-commutative10.2%
fma-define10.2%
add-exp-log10.1%
Applied egg-rr10.1%
associate-*r/10.1%
*-rgt-identity10.1%
+-commutative10.1%
associate--l+93.6%
+-inverses93.6%
metadata-eval93.6%
+-commutative93.6%
exp-prod92.4%
Simplified92.4%
pow-exp93.6%
Applied egg-rr93.6%
Final simplification93.6%
(FPCore (x) :precision binary64 (/ 1.0 (fma (cbrt x) (+ (cbrt x) (cbrt (+ 1.0 x))) (pow (+ 1.0 x) 0.6666666666666666))))
double code(double x) {
return 1.0 / fma(cbrt(x), (cbrt(x) + cbrt((1.0 + x))), pow((1.0 + x), 0.6666666666666666));
}
function code(x) return Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + cbrt(Float64(1.0 + x))), (Float64(1.0 + x) ^ 0.6666666666666666))) end
code[x_] := N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] + N[Power[N[(1.0 + x), $MachinePrecision], 0.6666666666666666], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + \sqrt[3]{1 + x}, {\left(1 + x\right)}^{0.6666666666666666}\right)}
\end{array}
Initial program 7.5%
flip3--7.8%
div-inv7.8%
rem-cube-cbrt7.6%
rem-cube-cbrt10.2%
+-commutative10.2%
distribute-rgt-out10.2%
+-commutative10.2%
fma-define10.2%
add-exp-log10.1%
Applied egg-rr10.1%
associate-*r/10.1%
*-rgt-identity10.1%
+-commutative10.1%
associate--l+93.6%
+-inverses93.6%
metadata-eval93.6%
+-commutative93.6%
exp-prod92.4%
Simplified92.4%
pow-exp93.6%
*-commutative93.6%
log1p-undefine93.6%
+-commutative93.6%
exp-to-pow93.0%
metadata-eval93.0%
pow-prod-up93.0%
pow1/394.5%
pow1/398.6%
Applied egg-rr98.6%
pow298.6%
pow1/393.0%
pow-pow93.0%
metadata-eval93.0%
Applied egg-rr93.0%
Final simplification93.0%
(FPCore (x) :precision binary64 (if (<= x 1.35e+154) (* 0.3333333333333333 (cbrt (/ 1.0 (pow x 2.0)))) (/ 1.0 (fma (cbrt x) (+ (cbrt x) (cbrt (+ 1.0 x))) 1.0))))
double code(double x) {
double tmp;
if (x <= 1.35e+154) {
tmp = 0.3333333333333333 * cbrt((1.0 / pow(x, 2.0)));
} else {
tmp = 1.0 / fma(cbrt(x), (cbrt(x) + cbrt((1.0 + x))), 1.0);
}
return tmp;
}
function code(x) tmp = 0.0 if (x <= 1.35e+154) tmp = Float64(0.3333333333333333 * cbrt(Float64(1.0 / (x ^ 2.0)))); else tmp = Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + cbrt(Float64(1.0 + x))), 1.0)); end return tmp end
code[x_] := If[LessEqual[x, 1.35e+154], N[(0.3333333333333333 * N[Power[N[(1.0 / N[Power[x, 2.0], $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq 1.35 \cdot 10^{+154}:\\
\;\;\;\;0.3333333333333333 \cdot \sqrt[3]{\frac{1}{{x}^{2}}}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + \sqrt[3]{1 + x}, 1\right)}\\
\end{array}
\end{array}
if x < 1.35000000000000003e154Initial program 10.8%
Taylor expanded in x around inf 93.7%
if 1.35000000000000003e154 < x Initial program 4.8%
flip3--4.8%
div-inv4.8%
rem-cube-cbrt2.9%
rem-cube-cbrt4.8%
+-commutative4.8%
distribute-rgt-out4.8%
+-commutative4.8%
fma-define4.8%
add-exp-log4.8%
Applied egg-rr4.8%
associate-*r/4.8%
*-rgt-identity4.8%
+-commutative4.8%
associate--l+92.3%
+-inverses92.3%
metadata-eval92.3%
+-commutative92.3%
exp-prod91.0%
Simplified91.0%
Taylor expanded in x around 0 20.0%
Final simplification54.2%
(FPCore (x) :precision binary64 (* 0.3333333333333333 (cbrt (/ 1.0 (pow x 2.0)))))
double code(double x) {
return 0.3333333333333333 * cbrt((1.0 / pow(x, 2.0)));
}
public static double code(double x) {
return 0.3333333333333333 * Math.cbrt((1.0 / Math.pow(x, 2.0)));
}
function code(x) return Float64(0.3333333333333333 * cbrt(Float64(1.0 / (x ^ 2.0)))) end
code[x_] := N[(0.3333333333333333 * N[Power[N[(1.0 / N[Power[x, 2.0], $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
0.3333333333333333 \cdot \sqrt[3]{\frac{1}{{x}^{2}}}
\end{array}
Initial program 7.5%
Taylor expanded in x around inf 46.1%
(FPCore (x) :precision binary64 (- (cbrt (+ 1.0 x)) (cbrt x)))
double code(double x) {
return cbrt((1.0 + x)) - cbrt(x);
}
public static double code(double x) {
return Math.cbrt((1.0 + x)) - Math.cbrt(x);
}
function code(x) return Float64(cbrt(Float64(1.0 + x)) - cbrt(x)) end
code[x_] := N[(N[Power[N[(1.0 + x), $MachinePrecision], 1/3], $MachinePrecision] - N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\sqrt[3]{1 + x} - \sqrt[3]{x}
\end{array}
Initial program 7.5%
Final simplification7.5%
(FPCore (x) :precision binary64 (- (cbrt x) (pow x 0.3333333333333333)))
double code(double x) {
return cbrt(x) - pow(x, 0.3333333333333333);
}
public static double code(double x) {
return Math.cbrt(x) - Math.pow(x, 0.3333333333333333);
}
function code(x) return Float64(cbrt(x) - (x ^ 0.3333333333333333)) end
code[x_] := N[(N[Power[x, 1/3], $MachinePrecision] - N[Power[x, 0.3333333333333333], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\sqrt[3]{x} - {x}^{0.3333333333333333}
\end{array}
Initial program 7.5%
pow1/38.4%
Applied egg-rr8.4%
Taylor expanded in x around inf 5.7%
(FPCore (x) :precision binary64 (+ 1.0 (cbrt x)))
double code(double x) {
return 1.0 + cbrt(x);
}
public static double code(double x) {
return 1.0 + Math.cbrt(x);
}
function code(x) return Float64(1.0 + cbrt(x)) end
code[x_] := N[(1.0 + N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
1 + \sqrt[3]{x}
\end{array}
Initial program 7.5%
Taylor expanded in x around 0 1.8%
sub-neg1.8%
rem-square-sqrt0.0%
fabs-sqr0.0%
rem-square-sqrt5.3%
fabs-neg5.3%
unpow1/35.3%
metadata-eval5.3%
pow-sqr5.3%
fabs-sqr5.3%
pow-sqr5.3%
metadata-eval5.3%
unpow1/35.3%
Simplified5.3%
(FPCore (x) :precision binary64 (let* ((t_0 (cbrt (+ x 1.0)))) (/ 1.0 (+ (+ (* t_0 t_0) (* (cbrt x) t_0)) (* (cbrt x) (cbrt x))))))
double code(double x) {
double t_0 = cbrt((x + 1.0));
return 1.0 / (((t_0 * t_0) + (cbrt(x) * t_0)) + (cbrt(x) * cbrt(x)));
}
public static double code(double x) {
double t_0 = Math.cbrt((x + 1.0));
return 1.0 / (((t_0 * t_0) + (Math.cbrt(x) * t_0)) + (Math.cbrt(x) * Math.cbrt(x)));
}
function code(x) t_0 = cbrt(Float64(x + 1.0)) return Float64(1.0 / Float64(Float64(Float64(t_0 * t_0) + Float64(cbrt(x) * t_0)) + Float64(cbrt(x) * cbrt(x)))) end
code[x_] := Block[{t$95$0 = N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision]}, N[(1.0 / N[(N[(N[(t$95$0 * t$95$0), $MachinePrecision] + N[(N[Power[x, 1/3], $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision] + N[(N[Power[x, 1/3], $MachinePrecision] * N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{x + 1}\\
\frac{1}{\left(t\_0 \cdot t\_0 + \sqrt[3]{x} \cdot t\_0\right) + \sqrt[3]{x} \cdot \sqrt[3]{x}}
\end{array}
\end{array}
herbie shell --seed 2024084
(FPCore (x)
:name "2cbrt (problem 3.3.4)"
:precision binary64
:pre (and (> x 1.0) (< x 1e+308))
:alt
(/ 1.0 (+ (+ (* (cbrt (+ x 1.0)) (cbrt (+ x 1.0))) (* (cbrt x) (cbrt (+ x 1.0)))) (* (cbrt x) (cbrt x))))
(- (cbrt (+ x 1.0)) (cbrt x)))