
(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 6 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 (+ x 1.0))))
(if (<= (- t_0 (cbrt x)) 0.0)
(* 0.3333333333333333 (/ (cbrt x) x))
(/
(- (+ x 1.0) x)
(+
(pow (+ x 1.0) 0.6666666666666666)
(+ (pow x 0.6666666666666666) (* (cbrt x) t_0)))))))
double code(double x) {
double t_0 = cbrt((x + 1.0));
double tmp;
if ((t_0 - cbrt(x)) <= 0.0) {
tmp = 0.3333333333333333 * (cbrt(x) / x);
} else {
tmp = ((x + 1.0) - x) / (pow((x + 1.0), 0.6666666666666666) + (pow(x, 0.6666666666666666) + (cbrt(x) * t_0)));
}
return tmp;
}
public static double code(double x) {
double t_0 = Math.cbrt((x + 1.0));
double tmp;
if ((t_0 - Math.cbrt(x)) <= 0.0) {
tmp = 0.3333333333333333 * (Math.cbrt(x) / x);
} else {
tmp = ((x + 1.0) - x) / (Math.pow((x + 1.0), 0.6666666666666666) + (Math.pow(x, 0.6666666666666666) + (Math.cbrt(x) * t_0)));
}
return tmp;
}
function code(x) t_0 = cbrt(Float64(x + 1.0)) tmp = 0.0 if (Float64(t_0 - cbrt(x)) <= 0.0) tmp = Float64(0.3333333333333333 * Float64(cbrt(x) / x)); else tmp = Float64(Float64(Float64(x + 1.0) - x) / Float64((Float64(x + 1.0) ^ 0.6666666666666666) + Float64((x ^ 0.6666666666666666) + Float64(cbrt(x) * t_0)))); end return tmp end
code[x_] := Block[{t$95$0 = N[Power[N[(x + 1.0), $MachinePrecision], 1/3], $MachinePrecision]}, If[LessEqual[N[(t$95$0 - N[Power[x, 1/3], $MachinePrecision]), $MachinePrecision], 0.0], N[(0.3333333333333333 * N[(N[Power[x, 1/3], $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision], N[(N[(N[(x + 1.0), $MachinePrecision] - x), $MachinePrecision] / N[(N[Power[N[(x + 1.0), $MachinePrecision], 0.6666666666666666], $MachinePrecision] + N[(N[Power[x, 0.6666666666666666], $MachinePrecision] + N[(N[Power[x, 1/3], $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{x + 1}\\
\mathbf{if}\;t\_0 - \sqrt[3]{x} \leq 0:\\
\;\;\;\;0.3333333333333333 \cdot \frac{\sqrt[3]{x}}{x}\\
\mathbf{else}:\\
\;\;\;\;\frac{\left(x + 1\right) - x}{{\left(x + 1\right)}^{0.6666666666666666} + \left({x}^{0.6666666666666666} + \sqrt[3]{x} \cdot t\_0\right)}\\
\end{array}
\end{array}
if (-.f64 (cbrt.f64 (+.f64 x #s(literal 1 binary64))) (cbrt.f64 x)) < 0.0Initial program 4.2%
Taylor expanded in x around inf
*-lowering-*.f64N/A
metadata-evalN/A
associate-*r/N/A
cbrt-lowering-cbrt.f64N/A
associate-*r/N/A
metadata-evalN/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f6450.3%
Simplified50.3%
associate-/r*N/A
frac-2negN/A
cbrt-divN/A
/-lowering-/.f64N/A
cbrt-lowering-cbrt.f64N/A
neg-lowering-neg.f64N/A
/-lowering-/.f64N/A
rem-cube-cbrtN/A
cube-negN/A
neg-mul-1N/A
unpow-prod-downN/A
metadata-evalN/A
rem-cube-cbrtN/A
*-commutativeN/A
cbrt-lowering-cbrt.f64N/A
*-commutativeN/A
metadata-evalN/A
rem-cube-cbrtN/A
unpow-prod-downN/A
neg-mul-1N/A
cube-negN/A
rem-cube-cbrtN/A
neg-lowering-neg.f6498.5%
Applied egg-rr98.5%
distribute-neg-fracN/A
metadata-evalN/A
/-lowering-/.f6498.5%
Applied egg-rr98.5%
cbrt-undivN/A
associate-/l/N/A
metadata-evalN/A
distribute-lft-neg-inN/A
frac-2negN/A
cbrt-divN/A
metadata-evalN/A
pow1/3N/A
pow2N/A
pow-powN/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
pow-divN/A
pow2N/A
pow-powN/A
pow1/3N/A
clear-numN/A
associate-/r*N/A
div-invN/A
Applied egg-rr99.2%
if 0.0 < (-.f64 (cbrt.f64 (+.f64 x #s(literal 1 binary64))) (cbrt.f64 x)) Initial program 56.8%
rem-exp-logN/A
pow1/3N/A
log-powN/A
exp-prodN/A
pow-lowering-pow.f64N/A
exp-lowering-exp.f64N/A
log-lowering-log.f6456.0%
Applied egg-rr56.0%
Applied egg-rr97.3%
Final simplification99.1%
(FPCore (x)
:precision binary64
(if (<= x 4e+14)
(/
(- (+ x 1.0) x)
(+
(pow (+ x 1.0) 0.6666666666666666)
(+ (pow x 0.6666666666666666) (cbrt (* x (+ x 1.0))))))
(* 0.3333333333333333 (/ (cbrt x) x))))
double code(double x) {
double tmp;
if (x <= 4e+14) {
tmp = ((x + 1.0) - x) / (pow((x + 1.0), 0.6666666666666666) + (pow(x, 0.6666666666666666) + cbrt((x * (x + 1.0)))));
} else {
tmp = 0.3333333333333333 * (cbrt(x) / x);
}
return tmp;
}
public static double code(double x) {
double tmp;
if (x <= 4e+14) {
tmp = ((x + 1.0) - x) / (Math.pow((x + 1.0), 0.6666666666666666) + (Math.pow(x, 0.6666666666666666) + Math.cbrt((x * (x + 1.0)))));
} else {
tmp = 0.3333333333333333 * (Math.cbrt(x) / x);
}
return tmp;
}
function code(x) tmp = 0.0 if (x <= 4e+14) tmp = Float64(Float64(Float64(x + 1.0) - x) / Float64((Float64(x + 1.0) ^ 0.6666666666666666) + Float64((x ^ 0.6666666666666666) + cbrt(Float64(x * Float64(x + 1.0)))))); else tmp = Float64(0.3333333333333333 * Float64(cbrt(x) / x)); end return tmp end
code[x_] := If[LessEqual[x, 4e+14], N[(N[(N[(x + 1.0), $MachinePrecision] - x), $MachinePrecision] / N[(N[Power[N[(x + 1.0), $MachinePrecision], 0.6666666666666666], $MachinePrecision] + N[(N[Power[x, 0.6666666666666666], $MachinePrecision] + N[Power[N[(x * N[(x + 1.0), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(0.3333333333333333 * N[(N[Power[x, 1/3], $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq 4 \cdot 10^{+14}:\\
\;\;\;\;\frac{\left(x + 1\right) - x}{{\left(x + 1\right)}^{0.6666666666666666} + \left({x}^{0.6666666666666666} + \sqrt[3]{x \cdot \left(x + 1\right)}\right)}\\
\mathbf{else}:\\
\;\;\;\;0.3333333333333333 \cdot \frac{\sqrt[3]{x}}{x}\\
\end{array}
\end{array}
if x < 4e14Initial program 56.8%
rem-exp-logN/A
pow1/3N/A
log-powN/A
exp-prodN/A
pow-lowering-pow.f64N/A
exp-lowering-exp.f64N/A
log-lowering-log.f6456.0%
Applied egg-rr56.0%
Applied egg-rr97.1%
if 4e14 < x Initial program 4.2%
Taylor expanded in x around inf
*-lowering-*.f64N/A
metadata-evalN/A
associate-*r/N/A
cbrt-lowering-cbrt.f64N/A
associate-*r/N/A
metadata-evalN/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f6450.3%
Simplified50.3%
associate-/r*N/A
frac-2negN/A
cbrt-divN/A
/-lowering-/.f64N/A
cbrt-lowering-cbrt.f64N/A
neg-lowering-neg.f64N/A
/-lowering-/.f64N/A
rem-cube-cbrtN/A
cube-negN/A
neg-mul-1N/A
unpow-prod-downN/A
metadata-evalN/A
rem-cube-cbrtN/A
*-commutativeN/A
cbrt-lowering-cbrt.f64N/A
*-commutativeN/A
metadata-evalN/A
rem-cube-cbrtN/A
unpow-prod-downN/A
neg-mul-1N/A
cube-negN/A
rem-cube-cbrtN/A
neg-lowering-neg.f6498.5%
Applied egg-rr98.5%
distribute-neg-fracN/A
metadata-evalN/A
/-lowering-/.f6498.5%
Applied egg-rr98.5%
cbrt-undivN/A
associate-/l/N/A
metadata-evalN/A
distribute-lft-neg-inN/A
frac-2negN/A
cbrt-divN/A
metadata-evalN/A
pow1/3N/A
pow2N/A
pow-powN/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
pow-divN/A
pow2N/A
pow-powN/A
pow1/3N/A
clear-numN/A
associate-/r*N/A
div-invN/A
Applied egg-rr99.2%
Final simplification99.1%
(FPCore (x) :precision binary64 (* 0.3333333333333333 (/ (cbrt x) x)))
double code(double x) {
return 0.3333333333333333 * (cbrt(x) / x);
}
public static double code(double x) {
return 0.3333333333333333 * (Math.cbrt(x) / x);
}
function code(x) return Float64(0.3333333333333333 * Float64(cbrt(x) / x)) end
code[x_] := N[(0.3333333333333333 * N[(N[Power[x, 1/3], $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
0.3333333333333333 \cdot \frac{\sqrt[3]{x}}{x}
\end{array}
Initial program 6.7%
Taylor expanded in x around inf
*-lowering-*.f64N/A
metadata-evalN/A
associate-*r/N/A
cbrt-lowering-cbrt.f64N/A
associate-*r/N/A
metadata-evalN/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f6450.9%
Simplified50.9%
associate-/r*N/A
frac-2negN/A
cbrt-divN/A
/-lowering-/.f64N/A
cbrt-lowering-cbrt.f64N/A
neg-lowering-neg.f64N/A
/-lowering-/.f64N/A
rem-cube-cbrtN/A
cube-negN/A
neg-mul-1N/A
unpow-prod-downN/A
metadata-evalN/A
rem-cube-cbrtN/A
*-commutativeN/A
cbrt-lowering-cbrt.f64N/A
*-commutativeN/A
metadata-evalN/A
rem-cube-cbrtN/A
unpow-prod-downN/A
neg-mul-1N/A
cube-negN/A
rem-cube-cbrtN/A
neg-lowering-neg.f6496.8%
Applied egg-rr96.8%
distribute-neg-fracN/A
metadata-evalN/A
/-lowering-/.f6496.8%
Applied egg-rr96.8%
cbrt-undivN/A
associate-/l/N/A
metadata-evalN/A
distribute-lft-neg-inN/A
frac-2negN/A
cbrt-divN/A
metadata-evalN/A
pow1/3N/A
pow2N/A
pow-powN/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
pow-divN/A
pow2N/A
pow-powN/A
pow1/3N/A
clear-numN/A
associate-/r*N/A
div-invN/A
Applied egg-rr97.5%
(FPCore (x) :precision binary64 (* 0.3333333333333333 (pow x -0.6666666666666666)))
double code(double x) {
return 0.3333333333333333 * pow(x, -0.6666666666666666);
}
real(8) function code(x)
real(8), intent (in) :: x
code = 0.3333333333333333d0 * (x ** (-0.6666666666666666d0))
end function
public static double code(double x) {
return 0.3333333333333333 * Math.pow(x, -0.6666666666666666);
}
def code(x): return 0.3333333333333333 * math.pow(x, -0.6666666666666666)
function code(x) return Float64(0.3333333333333333 * (x ^ -0.6666666666666666)) end
function tmp = code(x) tmp = 0.3333333333333333 * (x ^ -0.6666666666666666); end
code[x_] := N[(0.3333333333333333 * N[Power[x, -0.6666666666666666], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
0.3333333333333333 \cdot {x}^{-0.6666666666666666}
\end{array}
Initial program 6.7%
Taylor expanded in x around inf
*-lowering-*.f64N/A
metadata-evalN/A
associate-*r/N/A
cbrt-lowering-cbrt.f64N/A
associate-*r/N/A
metadata-evalN/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f6450.9%
Simplified50.9%
*-commutativeN/A
*-lowering-*.f64N/A
pow1/3N/A
inv-powN/A
pow-powN/A
pow2N/A
pow-powN/A
pow-lowering-pow.f64N/A
metadata-evalN/A
metadata-eval89.1%
Applied egg-rr89.1%
Final simplification89.1%
(FPCore (x) :precision binary64 (cbrt x))
double code(double x) {
return cbrt(x);
}
public static double code(double x) {
return Math.cbrt(x);
}
function code(x) return cbrt(x) end
code[x_] := N[Power[x, 1/3], $MachinePrecision]
\begin{array}{l}
\\
\sqrt[3]{x}
\end{array}
Initial program 6.7%
rem-exp-logN/A
pow1/3N/A
log-powN/A
exp-prodN/A
pow-lowering-pow.f64N/A
exp-lowering-exp.f64N/A
log-lowering-log.f646.9%
Applied egg-rr6.9%
Taylor expanded in x around inf
cbrt-lowering-cbrt.f645.4%
Simplified5.4%
(FPCore (x) :precision binary64 0.0)
double code(double x) {
return 0.0;
}
real(8) function code(x)
real(8), intent (in) :: x
code = 0.0d0
end function
public static double code(double x) {
return 0.0;
}
def code(x): return 0.0
function code(x) return 0.0 end
function tmp = code(x) tmp = 0.0; end
code[x_] := 0.0
\begin{array}{l}
\\
0
\end{array}
Initial program 6.7%
rem-exp-logN/A
pow1/3N/A
log-powN/A
exp-prodN/A
pow-lowering-pow.f64N/A
exp-lowering-exp.f64N/A
log-lowering-log.f646.9%
Applied egg-rr6.9%
Taylor expanded in x around inf
distribute-rgt1-inN/A
metadata-evalN/A
mul0-lftN/A
mul0-rgt4.1%
Simplified4.1%
(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 2024192
(FPCore (x)
:name "2cbrt (problem 3.3.4)"
:precision binary64
:pre (and (> x 1.0) (< x 1e+308))
:alt
(! :herbie-platform default (/ 1 (+ (* (cbrt (+ x 1)) (cbrt (+ x 1))) (* (cbrt x) (cbrt (+ x 1))) (* (cbrt x) (cbrt x)))))
(- (cbrt (+ x 1.0)) (cbrt x)))