Average Error: 59.7 → 2.2
Time: 2.5m
Precision: 64
Internal Precision: 1408
\[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\]
\[\left(-\frac{4}{\pi}\right) \cdot \log \left(\frac{\sqrt[3]{e^{\frac{-f}{\frac{4}{\pi}}} + e^{\frac{\pi}{4} \cdot f}} \cdot \sqrt[3]{e^{\frac{-f}{\frac{4}{\pi}}} + e^{\frac{\pi}{4} \cdot f}}}{\sqrt{(\pi \cdot \left((\left(\left(f \cdot f\right) \cdot \left(f \cdot \frac{1}{192}\right)\right) \cdot \left(\pi \cdot \pi\right) + \left(f \cdot \frac{1}{2}\right))_*\right) + \left(\frac{1}{61440} \cdot \left({\pi}^{5} \cdot {f}^{5}\right)\right))_*}}\right) + \left(-\frac{4}{\pi}\right) \cdot \log \left(\frac{\sqrt[3]{e^{\frac{-f}{\frac{4}{\pi}}} + e^{\frac{\pi}{4} \cdot f}}}{\sqrt{(\pi \cdot \left((\left(\left(f \cdot f\right) \cdot \left(f \cdot \frac{1}{192}\right)\right) \cdot \left(\pi \cdot \pi\right) + \left(f \cdot \frac{1}{2}\right))_*\right) + \left(\frac{1}{61440} \cdot \left({\pi}^{5} \cdot {f}^{5}\right)\right))_*}}\right)\]

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 2.2

    \[\leadsto -\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{\color{blue}{\frac{1}{61440} \cdot \left({\pi}^{5} \cdot {f}^{5}\right) + \left(\frac{1}{2} \cdot \left(\pi \cdot f\right) + \frac{1}{192} \cdot \left({\pi}^{3} \cdot {f}^{3}\right)\right)}}\right)\]
  3. Applied simplify2.2

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

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

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

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

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

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

Runtime

Time bar (total: 2.5m)Debug logProfile

herbie shell --seed '#(1070258749 1877548225 2229079127 1588002776 3179087814 1886870650)' +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)))))))))