\[{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\left(\frac{1}{3}\right)}\]
Test:
NMSE problem 3.3.4
Bits:
128 bits
Bits error versus x
Time: 20.9 s
Input Error: 9.6
Output Error: 12.9
Log:
Profile: 🕒
\(\begin{cases} {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {\left(\sqrt[3]{{x}^{\left(\frac{1}{3}\right)}}\right)}^3 & \text{when } x \le 4.6312522f+08 \\ (\left(\sqrt[3]{\frac{1}{{x}^{4}}}\right) * \frac{1}{3} + \left(\sqrt[3]{\frac{1}{x}}\right))_* - (\frac{1}{9} * \left(\sqrt[3]{\frac{1}{{x}^{7}}}\right) + \left({x}^{\frac{-1}{3}}\right))_* & \text{otherwise} \end{cases}\)

    if x < 4.6312522f+08

    1. Started with
      \[{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\left(\frac{1}{3}\right)}\]
      2.7
    2. Using strategy rm
      2.7
    3. Applied add-cube-cbrt to get
      \[{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - \color{red}{{x}^{\left(\frac{1}{3}\right)}} \leadsto {\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - \color{blue}{{\left(\sqrt[3]{{x}^{\left(\frac{1}{3}\right)}}\right)}^3}\]
      2.8

    if 4.6312522f+08 < x

    1. Started with
      \[{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\left(\frac{1}{3}\right)}\]
      20.3
    2. Using strategy rm
      20.3
    3. Applied expm1-log1p-u to get
      \[\color{red}{{\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\left(\frac{1}{3}\right)}} \leadsto \color{blue}{(e^{\log_* (1 + \left({\left(x + 1\right)}^{\left(\frac{1}{3}\right)} - {x}^{\left(\frac{1}{3}\right)}\right))} - 1)^*}\]
      20.3
    4. Using strategy rm
      20.3
    5. Applied add-sqr-sqrt to get
      \[(e^{\log_* (1 + \left(\color{red}{{\left(x + 1\right)}^{\left(\frac{1}{3}\right)}} - {x}^{\left(\frac{1}{3}\right)}\right))} - 1)^* \leadsto (e^{\log_* (1 + \left(\color{blue}{{\left(\sqrt{{\left(x + 1\right)}^{\left(\frac{1}{3}\right)}}\right)}^2} - {x}^{\left(\frac{1}{3}\right)}\right))} - 1)^*\]
      30.1
    6. Applied taylor to get
      \[(e^{\log_* (1 + \left({\left(\sqrt{{\left(x + 1\right)}^{\left(\frac{1}{3}\right)}}\right)}^2 - {x}^{\left(\frac{1}{3}\right)}\right))} - 1)^* \leadsto (e^{\log_* (1 + \left(\left(\frac{1}{3} \cdot {\left(\frac{1}{{x}^{4}}\right)}^{\frac{1}{3}} + {\left(\frac{1}{x}\right)}^{\frac{1}{3}}\right) - \left(\frac{1}{9} \cdot {\left(\frac{1}{{x}^{7}}\right)}^{\frac{1}{3}} + {x}^{\frac{-1}{3}}\right)\right))} - 1)^*\]
      20.4
    7. Taylor expanded around inf to get
      \[(e^{\log_* (1 + \color{red}{\left(\left(\frac{1}{3} \cdot {\left(\frac{1}{{x}^{4}}\right)}^{\frac{1}{3}} + {\left(\frac{1}{x}\right)}^{\frac{1}{3}}\right) - \left(\frac{1}{9} \cdot {\left(\frac{1}{{x}^{7}}\right)}^{\frac{1}{3}} + {x}^{\frac{-1}{3}}\right)\right)})} - 1)^* \leadsto (e^{\log_* (1 + \color{blue}{\left(\left(\frac{1}{3} \cdot {\left(\frac{1}{{x}^{4}}\right)}^{\frac{1}{3}} + {\left(\frac{1}{x}\right)}^{\frac{1}{3}}\right) - \left(\frac{1}{9} \cdot {\left(\frac{1}{{x}^{7}}\right)}^{\frac{1}{3}} + {x}^{\frac{-1}{3}}\right)\right)})} - 1)^*\]
      20.4
    8. Applied simplify to get
      \[(e^{\log_* (1 + \left(\left(\frac{1}{3} \cdot {\left(\frac{1}{{x}^{4}}\right)}^{\frac{1}{3}} + {\left(\frac{1}{x}\right)}^{\frac{1}{3}}\right) - \left(\frac{1}{9} \cdot {\left(\frac{1}{{x}^{7}}\right)}^{\frac{1}{3}} + {x}^{\frac{-1}{3}}\right)\right))} - 1)^* \leadsto (\left(\sqrt[3]{\frac{1}{{x}^{4}}}\right) * \frac{1}{3} + \left(\sqrt[3]{\frac{1}{x}}\right))_* - (\frac{1}{9} * \left(\sqrt[3]{\frac{1}{{x}^{7}}}\right) + \left({x}^{\frac{-1}{3}}\right))_*\]
      28.5

    9. Applied final simplification

  1. Removed slow pow expressions

Original test:


(lambda ((x default))
  #:name "NMSE problem 3.3.4"
  (- (pow (+ x 1) (/ 1 3)) (pow x (/ 1 3))))