Average Error: 59.4 → 0.1
Time: 1.2m
Precision: 64
Ground Truth: 128
\[\log \left(\frac{1 - \varepsilon}{1 + \varepsilon}\right)\]
\[\left(-\left(\varepsilon + \varepsilon\right)\right) + \left(\varepsilon \cdot \left(\varepsilon \cdot \frac{1}{3}\right) + {\varepsilon}^{4} \cdot \frac{1}{5}\right) \cdot \left(-\left(\varepsilon + \varepsilon\right)\right)\]

Error

Bits error versus eps

Target

Original59.4
Comparison0.1
Herbie0.1
\[ -2 \cdot \left(\left(\varepsilon + \frac{{\varepsilon}^{3}}{3}\right) + \frac{{\varepsilon}^{5}}{5}\right) \]

Derivation

  1. Initial program 59.4

    \[\log \left(\frac{1 - \varepsilon}{1 + \varepsilon}\right)\]
  2. Applied taylor 0.1

    \[\leadsto -\left(\frac{2}{3} \cdot {\varepsilon}^{3} + \left(2 \cdot \varepsilon + \frac{2}{5} \cdot {\varepsilon}^{5}\right)\right)\]
  3. Taylor expanded around 0 0.1

    \[\leadsto \color{blue}{-\left(\frac{2}{3} \cdot {\varepsilon}^{3} + \left(2 \cdot \varepsilon + \frac{2}{5} \cdot {\varepsilon}^{5}\right)\right)}\]
  4. Using strategy rm
  5. Applied add-cube-cbrt 1.5

    \[\leadsto -\color{blue}{{\left(\sqrt[3]{\frac{2}{3} \cdot {\varepsilon}^{3} + \left(2 \cdot \varepsilon + \frac{2}{5} \cdot {\varepsilon}^{5}\right)}\right)}^3}\]
  6. Applied simplify 1.5

    \[\leadsto -{\color{blue}{\left(\sqrt[3]{\left({\varepsilon}^{5} \cdot \frac{2}{5} + \varepsilon\right) + \left(\varepsilon + \frac{2}{3} \cdot {\varepsilon}^3\right)}\right)}}^3\]
  7. Applied taylor 34.9

    \[\leadsto -\left(\frac{1}{3} \cdot \left({\varepsilon}^2 \cdot e^{\log 2 + \log \varepsilon}\right) + \left(e^{\log 2 + \log \varepsilon} + \frac{1}{5} \cdot \left({\varepsilon}^{4} \cdot e^{\log 2 + \log \varepsilon}\right)\right)\right)\]
  8. Taylor expanded around 0 34.9

    \[\leadsto -\color{blue}{\left(\frac{1}{3} \cdot \left({\varepsilon}^2 \cdot e^{\log 2 + \log \varepsilon}\right) + \left(e^{\log 2 + \log \varepsilon} + \frac{1}{5} \cdot \left({\varepsilon}^{4} \cdot e^{\log 2 + \log \varepsilon}\right)\right)\right)}\]
  9. Applied simplify 0.1

    \[\leadsto \color{blue}{\left(-\left(\varepsilon + \varepsilon\right)\right) + \left(\varepsilon \cdot \left(\varepsilon \cdot \frac{1}{3}\right) + {\varepsilon}^{4} \cdot \frac{1}{5}\right) \cdot \left(-\left(\varepsilon + \varepsilon\right)\right)}\]
  10. Removed slow pow expressions

Runtime

Total time: 1.2m Debug log

Please include this information when filing a bug report:

herbie --seed '#(2203242623 426597144 979971308 414682266 34629041 1017857168)'
(FPCore (eps)
  :name "NMSE problem 3.4.3"

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

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