Average Error: 58.5 → 0.2
Time: 58.5s
Precision: 64
Internal Precision: 1408
\[\log \left(\frac{1 - \varepsilon}{1 + \varepsilon}\right)\]
\[(\left((\left(\frac{1}{3} \cdot \varepsilon\right) \cdot \left(\varepsilon \cdot \varepsilon\right) + \varepsilon)_*\right) \cdot \left(\sqrt[3]{-8}\right) + \left({\varepsilon}^{5} \cdot \frac{-2}{5}\right))_*\]

Error

Bits error versus eps

Target

Original58.5
Target0.2
Herbie0.2
\[-2 \cdot \left(\left(\varepsilon + \frac{{\varepsilon}^{3}}{3}\right) + \frac{{\varepsilon}^{5}}{5}\right)\]

Derivation

  1. Initial program 58.5

    \[\log \left(\frac{1 - \varepsilon}{1 + \varepsilon}\right)\]
  2. Taylor expanded around 0 0.2

    \[\leadsto \color{blue}{-\left(\frac{2}{3} \cdot {\varepsilon}^{3} + \left(\frac{2}{5} \cdot {\varepsilon}^{5} + 2 \cdot \varepsilon\right)\right)}\]
  3. Applied simplify0.2

    \[\leadsto \color{blue}{(\left((\frac{-2}{3} \cdot \left(\varepsilon \cdot \varepsilon\right) + -2)_*\right) \cdot \varepsilon + \left(\frac{-2}{5} \cdot {\varepsilon}^{5}\right))_*}\]
  4. Using strategy rm
  5. Applied add-cbrt-cube0.2

    \[\leadsto (\color{blue}{\left(\sqrt[3]{\left((\frac{-2}{3} \cdot \left(\varepsilon \cdot \varepsilon\right) + -2)_* \cdot (\frac{-2}{3} \cdot \left(\varepsilon \cdot \varepsilon\right) + -2)_*\right) \cdot (\frac{-2}{3} \cdot \left(\varepsilon \cdot \varepsilon\right) + -2)_*}\right)} \cdot \varepsilon + \left(\frac{-2}{5} \cdot {\varepsilon}^{5}\right))_*\]
  6. Applied simplify0.2

    \[\leadsto (\left(\sqrt[3]{\color{blue}{{\left((\left(\varepsilon \cdot \varepsilon\right) \cdot \frac{-2}{3} + -2)_*\right)}^{3}}}\right) \cdot \varepsilon + \left(\frac{-2}{5} \cdot {\varepsilon}^{5}\right))_*\]
  7. Taylor expanded around 0 62.9

    \[\leadsto (\color{blue}{\left({\left({-2}^{3}\right)}^{\frac{1}{3}} + \frac{1}{3} \cdot \left({\varepsilon}^{2} \cdot {-8}^{\frac{1}{3}}\right)\right)} \cdot \varepsilon + \left(\frac{-2}{5} \cdot {\varepsilon}^{5}\right))_*\]
  8. Applied simplify0.2

    \[\leadsto \color{blue}{(\left((\left(\frac{1}{3} \cdot \varepsilon\right) \cdot \left(\varepsilon \cdot \varepsilon\right) + \varepsilon)_*\right) \cdot \left(\sqrt[3]{-8}\right) + \left({\varepsilon}^{5} \cdot \frac{-2}{5}\right))_*}\]

Runtime

Time bar (total: 58.5s)Debug logProfile

herbie shell --seed '#(1070991898 1055468627 4280279443 640792587 928206309 3646738750)' +o rules:numerics
(FPCore (eps)
  :name "logq (problem 3.4.3)"

  :herbie-target
  (* -2 (+ (+ eps (/ (pow eps 3) 3)) (/ (pow eps 5) 5)))

  (log (/ (- 1 eps) (+ 1 eps))))