Average Error: 30.0 → 8.6
Time: 4.5s
Precision: binary64
\[\sqrt[3]{x + 1} - \sqrt[3]{x}\]
↓
\[\begin{array}{l} \mathbf{if}\;x \leq -692.6756517869045:\\ \;\;\;\;\left(0.3333333333333333 \cdot \sqrt[3]{\frac{1}{x \cdot x}} + 0.06172839506172839 \cdot \sqrt[3]{\frac{1}{{x}^{8}}}\right) - \left(0.1111111111111111 \cdot \sqrt[3]{\frac{1}{{x}^{5}}} + 0.0411522633744856 \cdot \sqrt[3]{\frac{1}{{x}^{11}}}\right)\\ \mathbf{elif}\;x \leq 3.839761141078324 \cdot 10^{-06}:\\ \;\;\;\;e^{\log \left(\sqrt[3]{x + 1} - \sqrt[3]{\sqrt[3]{x}} \cdot \left(\sqrt[3]{\sqrt[3]{x}} \cdot \sqrt[3]{\sqrt[3]{x}}\right)\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{{x}^{0.6666666666666666} + \sqrt[3]{x + 1} \cdot \left(\sqrt[3]{x + 1} + \sqrt[3]{x}\right)}\\ \end{array}\]
\sqrt[3]{x + 1} - \sqrt[3]{x}
↓
\begin{array}{l}
\mathbf{if}\;x \leq -692.6756517869045:\\
\;\;\;\;\left(0.3333333333333333 \cdot \sqrt[3]{\frac{1}{x \cdot x}} + 0.06172839506172839 \cdot \sqrt[3]{\frac{1}{{x}^{8}}}\right) - \left(0.1111111111111111 \cdot \sqrt[3]{\frac{1}{{x}^{5}}} + 0.0411522633744856 \cdot \sqrt[3]{\frac{1}{{x}^{11}}}\right)\\

\mathbf{elif}\;x \leq 3.839761141078324 \cdot 10^{-06}:\\
\;\;\;\;e^{\log \left(\sqrt[3]{x + 1} - \sqrt[3]{\sqrt[3]{x}} \cdot \left(\sqrt[3]{\sqrt[3]{x}} \cdot \sqrt[3]{\sqrt[3]{x}}\right)\right)}\\

\mathbf{else}:\\
\;\;\;\;\frac{1}{{x}^{0.6666666666666666} + \sqrt[3]{x + 1} \cdot \left(\sqrt[3]{x + 1} + \sqrt[3]{x}\right)}\\

\end{array}
(FPCore (x) :precision binary64 (- (cbrt (+ x 1.0)) (cbrt x)))
↓
(FPCore (x)
 :precision binary64
 (if (<= x -692.6756517869045)
   (-
    (+
     (* 0.3333333333333333 (cbrt (/ 1.0 (* x x))))
     (* 0.06172839506172839 (cbrt (/ 1.0 (pow x 8.0)))))
    (+
     (* 0.1111111111111111 (cbrt (/ 1.0 (pow x 5.0))))
     (* 0.0411522633744856 (cbrt (/ 1.0 (pow x 11.0))))))
   (if (<= x 3.839761141078324e-06)
     (exp
      (log
       (-
        (cbrt (+ x 1.0))
        (* (cbrt (cbrt x)) (* (cbrt (cbrt x)) (cbrt (cbrt x)))))))
     (/
      1.0
      (+
       (pow x 0.6666666666666666)
       (* (cbrt (+ x 1.0)) (+ (cbrt (+ x 1.0)) (cbrt x))))))))
double code(double x) {
	return cbrt(x + 1.0) - cbrt(x);
}
↓
double code(double x) {
	double tmp;
	if (x <= -692.6756517869045) {
		tmp = ((0.3333333333333333 * cbrt(1.0 / (x * x))) + (0.06172839506172839 * cbrt(1.0 / pow(x, 8.0)))) - ((0.1111111111111111 * cbrt(1.0 / pow(x, 5.0))) + (0.0411522633744856 * cbrt(1.0 / pow(x, 11.0))));
	} else if (x <= 3.839761141078324e-06) {
		tmp = exp(log(cbrt(x + 1.0) - (cbrt(cbrt(x)) * (cbrt(cbrt(x)) * cbrt(cbrt(x))))));
	} else {
		tmp = 1.0 / (pow(x, 0.6666666666666666) + (cbrt(x + 1.0) * (cbrt(x + 1.0) + cbrt(x))));
	}
	return tmp;
}

Error

Bits error versus x

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Split input into 3 regimes

  2. if x < -692.675651786904496

    1. Initial program 60.1

      \[\sqrt[3]{x + 1} - \sqrt[3]{x}\]

    2. Taylor expanded around inf 43.8

      \[\leadsto \color{blue}{\left(0.06172839506172839 \cdot {\left(\frac{1}{{x}^{8}}\right)}^{0.3333333333333333} + 0.3333333333333333 \cdot {\left(\frac{1}{{x}^{2}}\right)}^{0.3333333333333333}\right) - \left(0.0411522633744856 \cdot {\left(\frac{1}{{x}^{11}}\right)}^{0.3333333333333333} + 0.1111111111111111 \cdot {\left(\frac{1}{{x}^{5}}\right)}^{0.3333333333333333}\right)}\]

    3. Simplified30.2

      \[\leadsto \color{blue}{\left(0.3333333333333333 \cdot \sqrt[3]{\frac{1}{x \cdot x}} + 0.06172839506172839 \cdot \sqrt[3]{\frac{1}{{x}^{8}}}\right) - \left(0.1111111111111111 \cdot \sqrt[3]{\frac{1}{{x}^{5}}} + 0.0411522633744856 \cdot \sqrt[3]{\frac{1}{{x}^{11}}}\right)}\]

    if -692.675651786904496 < x < 3.8397611410783239e-6

    1. Initial program 0.0

      \[\sqrt[3]{x + 1} - \sqrt[3]{x}\]
    2. Using strategy rm

    3. Applied add-cube-cbrt_binary64_7950.1

      \[\leadsto \sqrt[3]{x + 1} - \color{blue}{\left(\sqrt[3]{\sqrt[3]{x}} \cdot \sqrt[3]{\sqrt[3]{x}}\right) \cdot \sqrt[3]{\sqrt[3]{x}}}\]
    4. Using strategy rm

    5. Applied add-exp-log_binary64_7980.1

      \[\leadsto \color{blue}{e^{\log \left(\sqrt[3]{x + 1} - \left(\sqrt[3]{\sqrt[3]{x}} \cdot \sqrt[3]{\sqrt[3]{x}}\right) \cdot \sqrt[3]{\sqrt[3]{x}}\right)}}\]

    if 3.8397611410783239e-6 < x

    1. Initial program 58.6

      \[\sqrt[3]{x + 1} - \sqrt[3]{x}\]
    2. Using strategy rm

    3. Applied flip3--_binary64_76458.4

      \[\leadsto \color{blue}{\frac{{\left(\sqrt[3]{x + 1}\right)}^{3} - {\left(\sqrt[3]{x}\right)}^{3}}{\sqrt[3]{x + 1} \cdot \sqrt[3]{x + 1} + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + \sqrt[3]{x + 1} \cdot \sqrt[3]{x}\right)}}\]

    4. Simplified1.0

      \[\leadsto \frac{\color{blue}{1}}{\sqrt[3]{x + 1} \cdot \sqrt[3]{x + 1} + \left(\sqrt[3]{x} \cdot \sqrt[3]{x} + \sqrt[3]{x + 1} \cdot \sqrt[3]{x}\right)}\]

    5. Simplified4.4

      \[\leadsto \frac{1}{\color{blue}{{x}^{0.6666666666666666} + \sqrt[3]{1 + x} \cdot \left(\sqrt[3]{x} + \sqrt[3]{1 + x}\right)}}\]
  3. Recombined 3 regimes into one program.

  4. Final simplification8.6

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -692.6756517869045:\\ \;\;\;\;\left(0.3333333333333333 \cdot \sqrt[3]{\frac{1}{x \cdot x}} + 0.06172839506172839 \cdot \sqrt[3]{\frac{1}{{x}^{8}}}\right) - \left(0.1111111111111111 \cdot \sqrt[3]{\frac{1}{{x}^{5}}} + 0.0411522633744856 \cdot \sqrt[3]{\frac{1}{{x}^{11}}}\right)\\ \mathbf{elif}\;x \leq 3.839761141078324 \cdot 10^{-06}:\\ \;\;\;\;e^{\log \left(\sqrt[3]{x + 1} - \sqrt[3]{\sqrt[3]{x}} \cdot \left(\sqrt[3]{\sqrt[3]{x}} \cdot \sqrt[3]{\sqrt[3]{x}}\right)\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{{x}^{0.6666666666666666} + \sqrt[3]{x + 1} \cdot \left(\sqrt[3]{x + 1} + \sqrt[3]{x}\right)}\\ \end{array}\]

Reproduce

herbie shell --seed 2021032 
(FPCore (x)
  :name "2cbrt (problem 3.3.4)"
  :precision binary64
  (- (cbrt (+ x 1.0)) (cbrt x)))