2cbrt (problem 3.3.4)

Percentage Accurate: 6.9% → 97.2%
Time: 7.0s
Alternatives: 5
Speedup: 1.9×

Specification

?
\[x > 1 \land x < 10^{+308}\]
\[\begin{array}{l} \\ \sqrt[3]{x + 1} - \sqrt[3]{x} \end{array} \]
(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:

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 5 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: 6.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt[3]{x + 1} - \sqrt[3]{x} \end{array} \]
(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}

Alternative 1: 97.2% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \frac{\sqrt[3]{x}}{x \cdot 3} \end{array} \]
(FPCore (x) :precision binary64 (/ (cbrt x) (* x 3.0)))
double code(double x) {
	return cbrt(x) / (x * 3.0);
}
public static double code(double x) {
	return Math.cbrt(x) / (x * 3.0);
}
function code(x)
	return Float64(cbrt(x) / Float64(x * 3.0))
end
code[x_] := N[(N[Power[x, 1/3], $MachinePrecision] / N[(x * 3.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\sqrt[3]{x}}{x \cdot 3}
\end{array}
Derivation
  1. Initial program 6.4%

    \[\sqrt[3]{x + 1} - \sqrt[3]{x} \]
  2. Add Preprocessing
  3. Taylor expanded in x around inf

    \[\leadsto \color{blue}{\frac{1}{3} \cdot \sqrt[3]{\frac{1}{{x}^{2}}}} \]
  4. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \color{blue}{\sqrt[3]{\frac{1}{{x}^{2}}} \cdot \frac{1}{3}} \]
    2. lower-*.f64N/A

      \[\leadsto \color{blue}{\sqrt[3]{\frac{1}{{x}^{2}}} \cdot \frac{1}{3}} \]
    3. metadata-evalN/A

      \[\leadsto \sqrt[3]{\frac{\color{blue}{-1 \cdot -1}}{{x}^{2}}} \cdot \frac{1}{3} \]
    4. associate-*r/N/A

      \[\leadsto \sqrt[3]{\color{blue}{-1 \cdot \frac{-1}{{x}^{2}}}} \cdot \frac{1}{3} \]
    5. lower-cbrt.f64N/A

      \[\leadsto \color{blue}{\sqrt[3]{-1 \cdot \frac{-1}{{x}^{2}}}} \cdot \frac{1}{3} \]
    6. unpow2N/A

      \[\leadsto \sqrt[3]{-1 \cdot \frac{-1}{\color{blue}{x \cdot x}}} \cdot \frac{1}{3} \]
    7. associate-/r*N/A

      \[\leadsto \sqrt[3]{-1 \cdot \color{blue}{\frac{\frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
    8. associate-*r/N/A

      \[\leadsto \sqrt[3]{\color{blue}{\frac{-1 \cdot \frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
    9. lower-/.f64N/A

      \[\leadsto \sqrt[3]{\color{blue}{\frac{-1 \cdot \frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
    10. associate-*r/N/A

      \[\leadsto \sqrt[3]{\frac{\color{blue}{\frac{-1 \cdot -1}{x}}}{x}} \cdot \frac{1}{3} \]
    11. metadata-evalN/A

      \[\leadsto \sqrt[3]{\frac{\frac{\color{blue}{1}}{x}}{x}} \cdot \frac{1}{3} \]
    12. lower-/.f6446.5

      \[\leadsto \sqrt[3]{\frac{\color{blue}{\frac{1}{x}}}{x}} \cdot 0.3333333333333333 \]
  5. Applied rewrites46.5%

    \[\leadsto \color{blue}{\sqrt[3]{\frac{\frac{1}{x}}{x}} \cdot 0.3333333333333333} \]
  6. Step-by-step derivation
    1. Applied rewrites96.8%

      \[\leadsto \frac{0.3333333333333333}{\color{blue}{{\left(\sqrt[3]{x}\right)}^{2}}} \]
    2. Applied rewrites97.4%

      \[\leadsto \frac{0.3333333333333333}{\frac{x}{\color{blue}{\sqrt[3]{x}}}} \]
    3. Step-by-step derivation
      1. Applied rewrites97.5%

        \[\leadsto \frac{\sqrt[3]{x}}{\color{blue}{x \cdot 3}} \]
      2. Add Preprocessing

      Alternative 2: 97.2% accurate, 1.8× speedup?

      \[\begin{array}{l} \\ \frac{\sqrt[3]{x}}{x} \cdot 0.3333333333333333 \end{array} \]
      (FPCore (x) :precision binary64 (* (/ (cbrt x) x) 0.3333333333333333))
      double code(double x) {
      	return (cbrt(x) / x) * 0.3333333333333333;
      }
      
      public static double code(double x) {
      	return (Math.cbrt(x) / x) * 0.3333333333333333;
      }
      
      function code(x)
      	return Float64(Float64(cbrt(x) / x) * 0.3333333333333333)
      end
      
      code[x_] := N[(N[(N[Power[x, 1/3], $MachinePrecision] / x), $MachinePrecision] * 0.3333333333333333), $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      \frac{\sqrt[3]{x}}{x} \cdot 0.3333333333333333
      \end{array}
      
      Derivation
      1. Initial program 6.4%

        \[\sqrt[3]{x + 1} - \sqrt[3]{x} \]
      2. Add Preprocessing
      3. Taylor expanded in x around inf

        \[\leadsto \color{blue}{\frac{1}{3} \cdot \sqrt[3]{\frac{1}{{x}^{2}}}} \]
      4. Step-by-step derivation
        1. *-commutativeN/A

          \[\leadsto \color{blue}{\sqrt[3]{\frac{1}{{x}^{2}}} \cdot \frac{1}{3}} \]
        2. lower-*.f64N/A

          \[\leadsto \color{blue}{\sqrt[3]{\frac{1}{{x}^{2}}} \cdot \frac{1}{3}} \]
        3. metadata-evalN/A

          \[\leadsto \sqrt[3]{\frac{\color{blue}{-1 \cdot -1}}{{x}^{2}}} \cdot \frac{1}{3} \]
        4. associate-*r/N/A

          \[\leadsto \sqrt[3]{\color{blue}{-1 \cdot \frac{-1}{{x}^{2}}}} \cdot \frac{1}{3} \]
        5. lower-cbrt.f64N/A

          \[\leadsto \color{blue}{\sqrt[3]{-1 \cdot \frac{-1}{{x}^{2}}}} \cdot \frac{1}{3} \]
        6. unpow2N/A

          \[\leadsto \sqrt[3]{-1 \cdot \frac{-1}{\color{blue}{x \cdot x}}} \cdot \frac{1}{3} \]
        7. associate-/r*N/A

          \[\leadsto \sqrt[3]{-1 \cdot \color{blue}{\frac{\frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
        8. associate-*r/N/A

          \[\leadsto \sqrt[3]{\color{blue}{\frac{-1 \cdot \frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
        9. lower-/.f64N/A

          \[\leadsto \sqrt[3]{\color{blue}{\frac{-1 \cdot \frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
        10. associate-*r/N/A

          \[\leadsto \sqrt[3]{\frac{\color{blue}{\frac{-1 \cdot -1}{x}}}{x}} \cdot \frac{1}{3} \]
        11. metadata-evalN/A

          \[\leadsto \sqrt[3]{\frac{\frac{\color{blue}{1}}{x}}{x}} \cdot \frac{1}{3} \]
        12. lower-/.f6446.5

          \[\leadsto \sqrt[3]{\frac{\color{blue}{\frac{1}{x}}}{x}} \cdot 0.3333333333333333 \]
      5. Applied rewrites46.5%

        \[\leadsto \color{blue}{\sqrt[3]{\frac{\frac{1}{x}}{x}} \cdot 0.3333333333333333} \]
      6. Step-by-step derivation
        1. Applied rewrites89.0%

          \[\leadsto {x}^{-0.6666666666666666} \cdot 0.3333333333333333 \]
        2. Step-by-step derivation
          1. Applied rewrites97.5%

            \[\leadsto \frac{\sqrt[3]{x}}{x} \cdot 0.3333333333333333 \]
          2. Add Preprocessing

          Alternative 3: 88.9% accurate, 1.8× speedup?

          \[\begin{array}{l} \\ \frac{0.3333333333333333}{{x}^{0.6666666666666666}} \end{array} \]
          (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}
          
          \\
          \frac{0.3333333333333333}{{x}^{0.6666666666666666}}
          \end{array}
          
          Derivation
          1. Initial program 6.4%

            \[\sqrt[3]{x + 1} - \sqrt[3]{x} \]
          2. Add Preprocessing
          3. Taylor expanded in x around inf

            \[\leadsto \color{blue}{\frac{1}{3} \cdot \sqrt[3]{\frac{1}{{x}^{2}}}} \]
          4. Step-by-step derivation
            1. *-commutativeN/A

              \[\leadsto \color{blue}{\sqrt[3]{\frac{1}{{x}^{2}}} \cdot \frac{1}{3}} \]
            2. lower-*.f64N/A

              \[\leadsto \color{blue}{\sqrt[3]{\frac{1}{{x}^{2}}} \cdot \frac{1}{3}} \]
            3. metadata-evalN/A

              \[\leadsto \sqrt[3]{\frac{\color{blue}{-1 \cdot -1}}{{x}^{2}}} \cdot \frac{1}{3} \]
            4. associate-*r/N/A

              \[\leadsto \sqrt[3]{\color{blue}{-1 \cdot \frac{-1}{{x}^{2}}}} \cdot \frac{1}{3} \]
            5. lower-cbrt.f64N/A

              \[\leadsto \color{blue}{\sqrt[3]{-1 \cdot \frac{-1}{{x}^{2}}}} \cdot \frac{1}{3} \]
            6. unpow2N/A

              \[\leadsto \sqrt[3]{-1 \cdot \frac{-1}{\color{blue}{x \cdot x}}} \cdot \frac{1}{3} \]
            7. associate-/r*N/A

              \[\leadsto \sqrt[3]{-1 \cdot \color{blue}{\frac{\frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
            8. associate-*r/N/A

              \[\leadsto \sqrt[3]{\color{blue}{\frac{-1 \cdot \frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
            9. lower-/.f64N/A

              \[\leadsto \sqrt[3]{\color{blue}{\frac{-1 \cdot \frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
            10. associate-*r/N/A

              \[\leadsto \sqrt[3]{\frac{\color{blue}{\frac{-1 \cdot -1}{x}}}{x}} \cdot \frac{1}{3} \]
            11. metadata-evalN/A

              \[\leadsto \sqrt[3]{\frac{\frac{\color{blue}{1}}{x}}{x}} \cdot \frac{1}{3} \]
            12. lower-/.f6446.5

              \[\leadsto \sqrt[3]{\frac{\color{blue}{\frac{1}{x}}}{x}} \cdot 0.3333333333333333 \]
          5. Applied rewrites46.5%

            \[\leadsto \color{blue}{\sqrt[3]{\frac{\frac{1}{x}}{x}} \cdot 0.3333333333333333} \]
          6. Step-by-step derivation
            1. Applied rewrites96.8%

              \[\leadsto \frac{0.3333333333333333}{\color{blue}{{\left(\sqrt[3]{x}\right)}^{2}}} \]
            2. Step-by-step derivation
              1. Applied rewrites89.0%

                \[\leadsto \frac{0.3333333333333333}{{x}^{\color{blue}{0.6666666666666666}}} \]
              2. Add Preprocessing

              Alternative 4: 88.9% accurate, 1.9× speedup?

              \[\begin{array}{l} \\ {x}^{-0.6666666666666666} \cdot 0.3333333333333333 \end{array} \]
              (FPCore (x)
               :precision binary64
               (* (pow x -0.6666666666666666) 0.3333333333333333))
              double code(double x) {
              	return pow(x, -0.6666666666666666) * 0.3333333333333333;
              }
              
              real(8) function code(x)
                  real(8), intent (in) :: x
                  code = (x ** (-0.6666666666666666d0)) * 0.3333333333333333d0
              end function
              
              public static double code(double x) {
              	return Math.pow(x, -0.6666666666666666) * 0.3333333333333333;
              }
              
              def code(x):
              	return math.pow(x, -0.6666666666666666) * 0.3333333333333333
              
              function code(x)
              	return Float64((x ^ -0.6666666666666666) * 0.3333333333333333)
              end
              
              function tmp = code(x)
              	tmp = (x ^ -0.6666666666666666) * 0.3333333333333333;
              end
              
              code[x_] := N[(N[Power[x, -0.6666666666666666], $MachinePrecision] * 0.3333333333333333), $MachinePrecision]
              
              \begin{array}{l}
              
              \\
              {x}^{-0.6666666666666666} \cdot 0.3333333333333333
              \end{array}
              
              Derivation
              1. Initial program 6.4%

                \[\sqrt[3]{x + 1} - \sqrt[3]{x} \]
              2. Add Preprocessing
              3. Taylor expanded in x around inf

                \[\leadsto \color{blue}{\frac{1}{3} \cdot \sqrt[3]{\frac{1}{{x}^{2}}}} \]
              4. Step-by-step derivation
                1. *-commutativeN/A

                  \[\leadsto \color{blue}{\sqrt[3]{\frac{1}{{x}^{2}}} \cdot \frac{1}{3}} \]
                2. lower-*.f64N/A

                  \[\leadsto \color{blue}{\sqrt[3]{\frac{1}{{x}^{2}}} \cdot \frac{1}{3}} \]
                3. metadata-evalN/A

                  \[\leadsto \sqrt[3]{\frac{\color{blue}{-1 \cdot -1}}{{x}^{2}}} \cdot \frac{1}{3} \]
                4. associate-*r/N/A

                  \[\leadsto \sqrt[3]{\color{blue}{-1 \cdot \frac{-1}{{x}^{2}}}} \cdot \frac{1}{3} \]
                5. lower-cbrt.f64N/A

                  \[\leadsto \color{blue}{\sqrt[3]{-1 \cdot \frac{-1}{{x}^{2}}}} \cdot \frac{1}{3} \]
                6. unpow2N/A

                  \[\leadsto \sqrt[3]{-1 \cdot \frac{-1}{\color{blue}{x \cdot x}}} \cdot \frac{1}{3} \]
                7. associate-/r*N/A

                  \[\leadsto \sqrt[3]{-1 \cdot \color{blue}{\frac{\frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
                8. associate-*r/N/A

                  \[\leadsto \sqrt[3]{\color{blue}{\frac{-1 \cdot \frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
                9. lower-/.f64N/A

                  \[\leadsto \sqrt[3]{\color{blue}{\frac{-1 \cdot \frac{-1}{x}}{x}}} \cdot \frac{1}{3} \]
                10. associate-*r/N/A

                  \[\leadsto \sqrt[3]{\frac{\color{blue}{\frac{-1 \cdot -1}{x}}}{x}} \cdot \frac{1}{3} \]
                11. metadata-evalN/A

                  \[\leadsto \sqrt[3]{\frac{\frac{\color{blue}{1}}{x}}{x}} \cdot \frac{1}{3} \]
                12. lower-/.f6446.5

                  \[\leadsto \sqrt[3]{\frac{\color{blue}{\frac{1}{x}}}{x}} \cdot 0.3333333333333333 \]
              5. Applied rewrites46.5%

                \[\leadsto \color{blue}{\sqrt[3]{\frac{\frac{1}{x}}{x}} \cdot 0.3333333333333333} \]
              6. Step-by-step derivation
                1. Applied rewrites89.0%

                  \[\leadsto {x}^{-0.6666666666666666} \cdot 0.3333333333333333 \]
                2. Add Preprocessing

                Alternative 5: 4.2% accurate, 207.0× speedup?

                \[\begin{array}{l} \\ 0 \end{array} \]
                (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}
                
                Derivation
                1. Initial program 6.4%

                  \[\sqrt[3]{x + 1} - \sqrt[3]{x} \]
                2. Add Preprocessing
                3. Step-by-step derivation
                  1. rem-exp-logN/A

                    \[\leadsto \sqrt[3]{\color{blue}{e^{\log \left(x + 1\right)}}} - \sqrt[3]{x} \]
                  2. unpow1N/A

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

                    \[\leadsto \sqrt[3]{e^{\color{blue}{1 \cdot \log \left(x + 1\right)}}} - \sqrt[3]{x} \]
                  4. rem-cube-cbrtN/A

                    \[\leadsto \sqrt[3]{e^{1 \cdot \log \color{blue}{\left({\left(\sqrt[3]{x + 1}\right)}^{3}\right)}}} - \sqrt[3]{x} \]
                  5. lift-cbrt.f64N/A

                    \[\leadsto \sqrt[3]{e^{1 \cdot \log \left({\color{blue}{\left(\sqrt[3]{x + 1}\right)}}^{3}\right)}} - \sqrt[3]{x} \]
                  6. pow-to-expN/A

                    \[\leadsto \sqrt[3]{e^{1 \cdot \log \color{blue}{\left(e^{\log \left(\sqrt[3]{x + 1}\right) \cdot 3}\right)}}} - \sqrt[3]{x} \]
                  7. rem-log-expN/A

                    \[\leadsto \sqrt[3]{e^{1 \cdot \color{blue}{\left(\log \left(\sqrt[3]{x + 1}\right) \cdot 3\right)}}} - \sqrt[3]{x} \]
                  8. exp-prodN/A

                    \[\leadsto \sqrt[3]{\color{blue}{{\left(e^{1}\right)}^{\left(\log \left(\sqrt[3]{x + 1}\right) \cdot 3\right)}}} - \sqrt[3]{x} \]
                  9. lower-pow.f64N/A

                    \[\leadsto \sqrt[3]{\color{blue}{{\left(e^{1}\right)}^{\left(\log \left(\sqrt[3]{x + 1}\right) \cdot 3\right)}}} - \sqrt[3]{x} \]
                  10. lower-exp.f64N/A

                    \[\leadsto \sqrt[3]{{\color{blue}{\left(e^{1}\right)}}^{\left(\log \left(\sqrt[3]{x + 1}\right) \cdot 3\right)}} - \sqrt[3]{x} \]
                  11. rem-log-expN/A

                    \[\leadsto \sqrt[3]{{\left(e^{1}\right)}^{\color{blue}{\log \left(e^{\log \left(\sqrt[3]{x + 1}\right) \cdot 3}\right)}}} - \sqrt[3]{x} \]
                  12. pow-to-expN/A

                    \[\leadsto \sqrt[3]{{\left(e^{1}\right)}^{\log \color{blue}{\left({\left(\sqrt[3]{x + 1}\right)}^{3}\right)}}} - \sqrt[3]{x} \]
                  13. lift-cbrt.f64N/A

                    \[\leadsto \sqrt[3]{{\left(e^{1}\right)}^{\log \left({\color{blue}{\left(\sqrt[3]{x + 1}\right)}}^{3}\right)}} - \sqrt[3]{x} \]
                  14. rem-cube-cbrtN/A

                    \[\leadsto \sqrt[3]{{\left(e^{1}\right)}^{\log \color{blue}{\left(x + 1\right)}}} - \sqrt[3]{x} \]
                  15. lift-+.f64N/A

                    \[\leadsto \sqrt[3]{{\left(e^{1}\right)}^{\log \color{blue}{\left(x + 1\right)}}} - \sqrt[3]{x} \]
                  16. +-commutativeN/A

                    \[\leadsto \sqrt[3]{{\left(e^{1}\right)}^{\log \color{blue}{\left(1 + x\right)}}} - \sqrt[3]{x} \]
                  17. lower-log1p.f644.7

                    \[\leadsto \sqrt[3]{{\left(e^{1}\right)}^{\color{blue}{\left(\mathsf{log1p}\left(x\right)\right)}}} - \sqrt[3]{x} \]
                4. Applied rewrites4.7%

                  \[\leadsto \sqrt[3]{\color{blue}{{\left(e^{1}\right)}^{\left(\mathsf{log1p}\left(x\right)\right)}}} - \sqrt[3]{x} \]
                5. Taylor expanded in x around inf

                  \[\leadsto \color{blue}{0} \]
                6. Step-by-step derivation
                  1. Applied rewrites4.2%

                    \[\leadsto \color{blue}{0} \]
                  2. Add Preprocessing

                  Developer Target 1: 98.5% accurate, 0.3× speedup?

                  \[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt[3]{x + 1}\\ \frac{1}{\left(t\_0 \cdot t\_0 + \sqrt[3]{x} \cdot t\_0\right) + \sqrt[3]{x} \cdot \sqrt[3]{x}} \end{array} \end{array} \]
                  (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}
                  

                  Reproduce

                  ?
                  herbie shell --seed 2024322 
                  (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)))