Average Error: 59.7 → 2.3
Time: 1.6m
Precision: 64
Internal Precision: 1344
\[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\]
\[\frac{-1}{\frac{\pi}{4}} \cdot \log \left(\frac{\sqrt[3]{e^{\frac{\pi}{4} \cdot \left(-f\right)} + e^{\frac{\pi}{4} \cdot f}} \cdot \sqrt[3]{e^{\frac{\pi}{4} \cdot \left(-f\right)} + e^{\frac{\pi}{4} \cdot f}}}{\sqrt{\left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \left({f}^{5} \cdot {\pi}^{5}\right) \cdot \frac{1}{61440}\right) + \left(f \cdot \pi\right) \cdot \frac{1}{2}}}\right) + \left(-\frac{\log \left(\frac{\sqrt[3]{e^{\frac{-\pi}{\frac{4}{f}}} + e^{\frac{f \cdot \pi}{4}}}}{\sqrt{(\pi \cdot \left((\left(\left(\frac{1}{192} \cdot f\right) \cdot \left(f \cdot f\right)\right) \cdot \left(\pi \cdot \pi\right) + \left(f \cdot \frac{1}{2}\right))_*\right) + \left(\left({f}^{5} \cdot \frac{1}{61440}\right) \cdot {\pi}^{5}\right))_*}}\right)}{\frac{\pi}{4}}\right)\]

Error

Bits error versus f

Derivation

  1. Initial program 59.7

    \[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\]
  2. Taylor expanded around 0 2.3

    \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}}\right)\]
  3. Using strategy rm
  4. Applied add-sqr-sqrt2.3

    \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{\sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)} \cdot \sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}}}\right)\]
  5. Applied add-cube-cbrt2.3

    \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\color{blue}{\left(\sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}} \cdot \sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}\right) \cdot \sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}}}{\sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)} \cdot \sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}}\right)\]
  6. Applied times-frac2.3

    \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \color{blue}{\left(\frac{\sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}} \cdot \sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}}{\sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}} \cdot \frac{\sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}}{\sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}}\right)}\]
  7. Applied log-prod2.4

    \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \color{blue}{\left(\log \left(\frac{\sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}} \cdot \sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}}{\sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}}\right) + \log \left(\frac{\sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}}{\sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}}\right)\right)}\]
  8. Applied distribute-lft-in2.3

    \[\leadsto -\color{blue}{\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}} \cdot \sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}}{\sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}}\right) + \frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}}{\sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}}\right)\right)}\]
  9. Simplified2.3

    \[\leadsto -\left(\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{\sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}} \cdot \sqrt[3]{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}}{\sqrt{\frac{1}{2} \cdot \left(f \cdot \pi\right) + \left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \frac{1}{61440} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)}}\right) + \color{blue}{\frac{\log \left(\frac{\sqrt[3]{e^{\frac{-\pi}{\frac{4}{f}}} + e^{\frac{f \cdot \pi}{4}}}}{\sqrt{(\pi \cdot \left((\left(\left(\frac{1}{192} \cdot f\right) \cdot \left(f \cdot f\right)\right) \cdot \left(\pi \cdot \pi\right) + \left(\frac{1}{2} \cdot f\right))_*\right) + \left({\pi}^{5} \cdot \left({f}^{5} \cdot \frac{1}{61440}\right)\right))_*}}\right)}{\frac{\pi}{4}}}\right)\]
  10. Final simplification2.3

    \[\leadsto \frac{-1}{\frac{\pi}{4}} \cdot \log \left(\frac{\sqrt[3]{e^{\frac{\pi}{4} \cdot \left(-f\right)} + e^{\frac{\pi}{4} \cdot f}} \cdot \sqrt[3]{e^{\frac{\pi}{4} \cdot \left(-f\right)} + e^{\frac{\pi}{4} \cdot f}}}{\sqrt{\left(\frac{1}{192} \cdot \left({f}^{3} \cdot {\pi}^{3}\right) + \left({f}^{5} \cdot {\pi}^{5}\right) \cdot \frac{1}{61440}\right) + \left(f \cdot \pi\right) \cdot \frac{1}{2}}}\right) + \left(-\frac{\log \left(\frac{\sqrt[3]{e^{\frac{-\pi}{\frac{4}{f}}} + e^{\frac{f \cdot \pi}{4}}}}{\sqrt{(\pi \cdot \left((\left(\left(\frac{1}{192} \cdot f\right) \cdot \left(f \cdot f\right)\right) \cdot \left(\pi \cdot \pi\right) + \left(f \cdot \frac{1}{2}\right))_*\right) + \left(\left({f}^{5} \cdot \frac{1}{61440}\right) \cdot {\pi}^{5}\right))_*}}\right)}{\frac{\pi}{4}}\right)\]

Runtime

Time bar (total: 1.6m)Debug logProfile

BaselineHerbieOracleSpan%
Regimes2.32.31.60.70%
herbie shell --seed 2018285 +o rules:numerics
(FPCore (f)
  :name "VandenBroeck and Keller, Equation (20)"
  (- (* (/ 1 (/ PI 4)) (log (/ (+ (exp (* (/ PI 4) f)) (exp (- (* (/ PI 4) f)))) (- (exp (* (/ PI 4) f)) (exp (- (* (/ PI 4) f)))))))))