Average Error: 59.7 → 2.3
Time: 1.7m
Precision: 64
Internal Precision: 1344
\[-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{e^{\frac{\pi}{4} \cdot f} + e^{-\frac{\pi}{4} \cdot f}}{e^{\frac{\pi}{4} \cdot f} - e^{-\frac{\pi}{4} \cdot f}}\right)\]
\[-\left(\left(\left(f \cdot f\right) \cdot \left(\frac{1}{12} \cdot \pi\right) + \left(\left(\pi \cdot \pi\right) \cdot \left(\pi \cdot \frac{-7}{5760}\right)\right) \cdot {f}^{4}\right) - \left(\frac{4}{\pi} \cdot \left(\log f - \log 4\right) + \frac{4}{\pi} \cdot \log \pi\right)\right)\]

Error

Bits error versus f

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Your Program's Arguments

Results

Enter valid numbers for all inputs

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

    \[\leadsto -\color{blue}{\left(\left(4 \cdot \frac{\log \left(\frac{4}{\pi}\right)}{\pi} + \frac{1}{12} \cdot \left({f}^{2} \cdot \pi\right)\right) - \left(4 \cdot \frac{\log f}{\pi} + \frac{7}{5760} \cdot \left({f}^{4} \cdot {\pi}^{3}\right)\right)\right)}\]
  3. Simplified2.2

    \[\leadsto -\color{blue}{\left(\left(\left(\frac{1}{12} \cdot \pi\right) \cdot \left(f \cdot f\right) + {f}^{4} \cdot \left(\left(\pi \cdot \pi\right) \cdot \left(\frac{-7}{5760} \cdot \pi\right)\right)\right) - \frac{4}{\pi} \cdot \left(\log f - \log \left(\frac{4}{\pi}\right)\right)\right)}\]
  4. Using strategy rm
  5. Applied log-div2.2

    \[\leadsto -\left(\left(\left(\frac{1}{12} \cdot \pi\right) \cdot \left(f \cdot f\right) + {f}^{4} \cdot \left(\left(\pi \cdot \pi\right) \cdot \left(\frac{-7}{5760} \cdot \pi\right)\right)\right) - \frac{4}{\pi} \cdot \left(\log f - \color{blue}{\left(\log 4 - \log \pi\right)}\right)\right)\]
  6. Applied associate--r-2.3

    \[\leadsto -\left(\left(\left(\frac{1}{12} \cdot \pi\right) \cdot \left(f \cdot f\right) + {f}^{4} \cdot \left(\left(\pi \cdot \pi\right) \cdot \left(\frac{-7}{5760} \cdot \pi\right)\right)\right) - \frac{4}{\pi} \cdot \color{blue}{\left(\left(\log f - \log 4\right) + \log \pi\right)}\right)\]
  7. Applied distribute-lft-in2.3

    \[\leadsto -\left(\left(\left(\frac{1}{12} \cdot \pi\right) \cdot \left(f \cdot f\right) + {f}^{4} \cdot \left(\left(\pi \cdot \pi\right) \cdot \left(\frac{-7}{5760} \cdot \pi\right)\right)\right) - \color{blue}{\left(\frac{4}{\pi} \cdot \left(\log f - \log 4\right) + \frac{4}{\pi} \cdot \log \pi\right)}\right)\]
  8. Using strategy rm
  9. Applied *-commutative2.3

    \[\leadsto -\left(\left(\left(\frac{1}{12} \cdot \pi\right) \cdot \left(f \cdot f\right) + {f}^{4} \cdot \left(\left(\pi \cdot \pi\right) \cdot \left(\frac{-7}{5760} \cdot \pi\right)\right)\right) - \left(\color{blue}{\left(\log f - \log 4\right) \cdot \frac{4}{\pi}} + \frac{4}{\pi} \cdot \log \pi\right)\right)\]
  10. Using strategy rm
  11. Applied *-commutative2.3

    \[\leadsto -\left(\left(\left(\frac{1}{12} \cdot \pi\right) \cdot \left(f \cdot f\right) + {f}^{4} \cdot \left(\left(\pi \cdot \pi\right) \cdot \left(\frac{-7}{5760} \cdot \pi\right)\right)\right) - \left(\color{blue}{\frac{4}{\pi} \cdot \left(\log f - \log 4\right)} + \frac{4}{\pi} \cdot \log \pi\right)\right)\]
  12. Final simplification2.3

    \[\leadsto -\left(\left(\left(f \cdot f\right) \cdot \left(\frac{1}{12} \cdot \pi\right) + \left(\left(\pi \cdot \pi\right) \cdot \left(\pi \cdot \frac{-7}{5760}\right)\right) \cdot {f}^{4}\right) - \left(\frac{4}{\pi} \cdot \left(\log f - \log 4\right) + \frac{4}{\pi} \cdot \log \pi\right)\right)\]

Runtime

Time bar (total: 1.7m)Debug logProfile

herbie shell --seed 2018251 
(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)))))))))