Average Error: 34.4 → 0.1
Time: 21.5s
Precision: 64
Ground Truth: 128
\[\left(e^{x} - 2\right) + e^{-x}\]
⬇
\[\frac{1}{12} \cdot {x}^{4} + \left({x}^2 + \frac{1}{360} \cdot {x}^{6}\right)\]

Error

Bits error versus x

Target

Original34.4
Comparison8.6
Herbie0.1
\[ 4 \cdot {\left(\sinh \left(\frac{x}{2}\right)\right)}^2 \]

Derivation

  1. Initial program 34.4

    \[\left(e^{x} - 2\right) + e^{-x}\]

  2. Applied taylor 0.1

    \[\leadsto \frac{1}{12} \cdot {x}^{4} + \left({x}^2 + \frac{1}{360} \cdot {x}^{6}\right)\]

  3. Taylor expanded around 0 0.1

    \[\leadsto \color{blue}{\frac{1}{12} \cdot {x}^{4} + \left({x}^2 + \frac{1}{360} \cdot {x}^{6}\right)}\]
  4. Removed slow pow expressions

Runtime

Total time: 21.5s Debug log

Please include this information when filing a bug report:

herbie --seed '#(1226832526 4008574 3523729426 889023147 2109088460 1504769009)'
(FPCore (x)
  :name "NMSE problem 3.3.7"

  :target
  (* 4 (sqr (sinh (/ x 2))))

  (+ (- (exp x) 2) (exp (- x))))