
(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 7 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
(pow
(/
(*
x
(+
(*
-0.05555555555555555
(* (cbrt (/ 1.0 (pow x 4.0))) (/ 1.0 (sqrt 0.3333333333333333))))
(* (sqrt 0.3333333333333333) (cbrt (/ 1.0 x)))))
x)
2.0))
double code(double x) {
return pow(((x * ((-0.05555555555555555 * (cbrt((1.0 / pow(x, 4.0))) * (1.0 / sqrt(0.3333333333333333)))) + (sqrt(0.3333333333333333) * cbrt((1.0 / x))))) / x), 2.0);
}
public static double code(double x) {
return Math.pow(((x * ((-0.05555555555555555 * (Math.cbrt((1.0 / Math.pow(x, 4.0))) * (1.0 / Math.sqrt(0.3333333333333333)))) + (Math.sqrt(0.3333333333333333) * Math.cbrt((1.0 / x))))) / x), 2.0);
}
function code(x) return Float64(Float64(x * Float64(Float64(-0.05555555555555555 * Float64(cbrt(Float64(1.0 / (x ^ 4.0))) * Float64(1.0 / sqrt(0.3333333333333333)))) + Float64(sqrt(0.3333333333333333) * cbrt(Float64(1.0 / x))))) / x) ^ 2.0 end
code[x_] := N[Power[N[(N[(x * N[(N[(-0.05555555555555555 * N[(N[Power[N[(1.0 / N[Power[x, 4.0], $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision] * N[(1.0 / N[Sqrt[0.3333333333333333], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[Sqrt[0.3333333333333333], $MachinePrecision] * N[Power[N[(1.0 / x), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision], 2.0], $MachinePrecision]
\begin{array}{l}
\\
{\left(\frac{x \cdot \left(-0.05555555555555555 \cdot \left(\sqrt[3]{\frac{1}{{x}^{4}}} \cdot \frac{1}{\sqrt{0.3333333333333333}}\right) + \sqrt{0.3333333333333333} \cdot \sqrt[3]{\frac{1}{x}}\right)}{x}\right)}^{2}
\end{array}
Initial program 5.3%
Taylor expanded in x around inf 26.5%
add-sqr-sqrt26.4%
pow226.4%
sqrt-div26.4%
+-commutative26.4%
fma-define26.4%
*-commutative26.4%
sqrt-pow127.5%
metadata-eval27.5%
pow127.5%
Applied egg-rr27.5%
Taylor expanded in x around inf 97.7%
Final simplification97.7%
(FPCore (x)
:precision binary64
(if (<= x 1.55e+231)
(*
(/ 1.0 x)
(/
(fma
0.3333333333333333
(pow (cbrt x) 4.0)
(cbrt (* x -0.0013717421124828531)))
x))
(/
1.0
(fma
(cbrt x)
(+ (cbrt x) (cbrt (+ x 1.0)))
(exp (* (log1p x) 0.6666666666666666))))))
double code(double x) {
double tmp;
if (x <= 1.55e+231) {
tmp = (1.0 / x) * (fma(0.3333333333333333, pow(cbrt(x), 4.0), cbrt((x * -0.0013717421124828531))) / x);
} else {
tmp = 1.0 / fma(cbrt(x), (cbrt(x) + cbrt((x + 1.0))), exp((log1p(x) * 0.6666666666666666)));
}
return tmp;
}
function code(x) tmp = 0.0 if (x <= 1.55e+231) tmp = Float64(Float64(1.0 / x) * Float64(fma(0.3333333333333333, (cbrt(x) ^ 4.0), cbrt(Float64(x * -0.0013717421124828531))) / x)); else tmp = Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + cbrt(Float64(x + 1.0))), exp(Float64(log1p(x) * 0.6666666666666666)))); end return tmp end
code[x_] := If[LessEqual[x, 1.55e+231], N[(N[(1.0 / x), $MachinePrecision] * N[(N[(0.3333333333333333 * N[Power[N[Power[x, 1/3], $MachinePrecision], 4.0], $MachinePrecision] + N[Power[N[(x * -0.0013717421124828531), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] + N[Exp[N[(N[Log[1 + x], $MachinePrecision] * 0.6666666666666666), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq 1.55 \cdot 10^{+231}:\\
\;\;\;\;\frac{1}{x} \cdot \frac{\mathsf{fma}\left(0.3333333333333333, {\left(\sqrt[3]{x}\right)}^{4}, \sqrt[3]{x \cdot -0.0013717421124828531}\right)}{x}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + \sqrt[3]{x + 1}, e^{\mathsf{log1p}\left(x\right) \cdot 0.6666666666666666}\right)}\\
\end{array}
\end{array}
if x < 1.54999999999999995e231Initial program 5.4%
Taylor expanded in x around inf 33.1%
pow1/330.7%
pow-pow62.5%
metadata-eval62.5%
Applied egg-rr62.5%
Applied egg-rr97.5%
if 1.54999999999999995e231 < x Initial program 5.1%
flip3--5.1%
div-inv5.1%
rem-cube-cbrt3.0%
rem-cube-cbrt5.1%
+-commutative5.1%
distribute-rgt-out5.1%
+-commutative5.1%
fma-define5.1%
add-exp-log5.1%
Applied egg-rr5.1%
associate-*r/5.1%
*-rgt-identity5.1%
+-commutative5.1%
associate--l+91.3%
+-inverses91.3%
metadata-eval91.3%
+-commutative91.3%
exp-prod90.5%
Simplified90.5%
add-exp-log90.8%
log-pow91.3%
rem-log-exp91.3%
Applied egg-rr91.3%
Final simplification96.2%
(FPCore (x)
:precision binary64
(if (<= x 1.55e+231)
(*
(/ 1.0 x)
(/
(fma
0.3333333333333333
(pow (cbrt x) 4.0)
(cbrt (* x -0.0013717421124828531)))
x))
(/ 1.0 (fma (cbrt x) (+ (cbrt x) (cbrt (+ x 1.0))) 1.0))))
double code(double x) {
double tmp;
if (x <= 1.55e+231) {
tmp = (1.0 / x) * (fma(0.3333333333333333, pow(cbrt(x), 4.0), cbrt((x * -0.0013717421124828531))) / x);
} else {
tmp = 1.0 / fma(cbrt(x), (cbrt(x) + cbrt((x + 1.0))), 1.0);
}
return tmp;
}
function code(x) tmp = 0.0 if (x <= 1.55e+231) tmp = Float64(Float64(1.0 / x) * Float64(fma(0.3333333333333333, (cbrt(x) ^ 4.0), cbrt(Float64(x * -0.0013717421124828531))) / x)); else tmp = Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + cbrt(Float64(x + 1.0))), 1.0)); end return tmp end
code[x_] := If[LessEqual[x, 1.55e+231], N[(N[(1.0 / x), $MachinePrecision] * N[(N[(0.3333333333333333 * N[Power[N[Power[x, 1/3], $MachinePrecision], 4.0], $MachinePrecision] + N[Power[N[(x * -0.0013717421124828531), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq 1.55 \cdot 10^{+231}:\\
\;\;\;\;\frac{1}{x} \cdot \frac{\mathsf{fma}\left(0.3333333333333333, {\left(\sqrt[3]{x}\right)}^{4}, \sqrt[3]{x \cdot -0.0013717421124828531}\right)}{x}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + \sqrt[3]{x + 1}, 1\right)}\\
\end{array}
\end{array}
if x < 1.54999999999999995e231Initial program 5.4%
Taylor expanded in x around inf 33.1%
pow1/330.7%
pow-pow62.5%
metadata-eval62.5%
Applied egg-rr62.5%
Applied egg-rr97.5%
if 1.54999999999999995e231 < x Initial program 5.1%
flip3--5.1%
div-inv5.1%
rem-cube-cbrt3.0%
rem-cube-cbrt5.1%
+-commutative5.1%
distribute-rgt-out5.1%
+-commutative5.1%
fma-define5.1%
add-exp-log5.1%
Applied egg-rr5.1%
associate-*r/5.1%
*-rgt-identity5.1%
+-commutative5.1%
associate--l+91.3%
+-inverses91.3%
metadata-eval91.3%
+-commutative91.3%
exp-prod90.5%
Simplified90.5%
Taylor expanded in x around 0 20.0%
Final simplification82.0%
(FPCore (x)
:precision binary64
(if (<= x 1.35e+154)
(/
(+ (* (cbrt x) -0.1111111111111111) (* 0.3333333333333333 (* x (cbrt x))))
(pow x 2.0))
(/ 1.0 (fma (cbrt x) (+ (cbrt x) (cbrt (+ x 1.0))) 1.0))))
double code(double x) {
double tmp;
if (x <= 1.35e+154) {
tmp = ((cbrt(x) * -0.1111111111111111) + (0.3333333333333333 * (x * cbrt(x)))) / pow(x, 2.0);
} else {
tmp = 1.0 / fma(cbrt(x), (cbrt(x) + cbrt((x + 1.0))), 1.0);
}
return tmp;
}
function code(x) tmp = 0.0 if (x <= 1.35e+154) tmp = Float64(Float64(Float64(cbrt(x) * -0.1111111111111111) + Float64(0.3333333333333333 * Float64(x * cbrt(x)))) / (x ^ 2.0)); else tmp = Float64(1.0 / fma(cbrt(x), Float64(cbrt(x) + cbrt(Float64(x + 1.0))), 1.0)); end return tmp end
code[x_] := If[LessEqual[x, 1.35e+154], N[(N[(N[(N[Power[x, 1/3], $MachinePrecision] * -0.1111111111111111), $MachinePrecision] + N[(0.3333333333333333 * N[(x * N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[x, 2.0], $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[Power[x, 1/3], $MachinePrecision] * N[(N[Power[x, 1/3], $MachinePrecision] + N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq 1.35 \cdot 10^{+154}:\\
\;\;\;\;\frac{\sqrt[3]{x} \cdot -0.1111111111111111 + 0.3333333333333333 \cdot \left(x \cdot \sqrt[3]{x}\right)}{{x}^{2}}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(\sqrt[3]{x}, \sqrt[3]{x} + \sqrt[3]{x + 1}, 1\right)}\\
\end{array}
\end{array}
if x < 1.35000000000000003e154Initial program 5.9%
Taylor expanded in x around inf 48.8%
pow1/345.3%
pow-pow90.1%
metadata-eval90.1%
Applied egg-rr90.1%
metadata-eval90.1%
pow-pow90.1%
pow1/397.3%
metadata-eval97.3%
pow-sqr97.3%
unpow297.3%
associate-*l*97.2%
unpow297.2%
cube-mult97.3%
rem-cube-cbrt98.6%
Applied egg-rr98.6%
if 1.35000000000000003e154 < x Initial program 4.7%
flip3--4.7%
div-inv4.7%
rem-cube-cbrt3.2%
rem-cube-cbrt4.7%
+-commutative4.7%
distribute-rgt-out4.7%
+-commutative4.7%
fma-define4.7%
add-exp-log4.7%
Applied egg-rr4.7%
associate-*r/4.7%
*-rgt-identity4.7%
+-commutative4.7%
associate--l+91.8%
+-inverses91.8%
metadata-eval91.8%
+-commutative91.8%
exp-prod90.9%
Simplified90.9%
Taylor expanded in x around 0 20.0%
Final simplification62.6%
(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 5.3%
Taylor expanded in x around inf 54.9%
Final simplification54.9%
(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 5.3%
Taylor expanded in x around inf 4.1%
pow1/35.9%
Applied egg-rr5.9%
Final simplification5.9%
(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 5.3%
Taylor expanded in x around 0 1.8%
sub-neg1.8%
rem-square-sqrt0.0%
fabs-sqr0.0%
rem-square-sqrt5.4%
fabs-neg5.4%
unpow1/35.4%
metadata-eval5.4%
pow-sqr5.4%
fabs-sqr5.4%
pow-sqr5.4%
metadata-eval5.4%
unpow1/35.4%
Simplified5.4%
Final simplification5.4%
(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 2024081
(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)))