Average Error: 58.7 → 0.2
Time: 36.5s
Precision: 64
Internal Precision: 1344
\[\frac{1}{2} \cdot \log \left(\frac{1 + x}{1 - x}\right)\]
↓
\[\left(\left(\frac{1}{3} \cdot x\right) \cdot \left(x \cdot x\right) + {x}^{5} \cdot \frac{1}{5}\right) + x\]

Error

Bits error versus x

Derivation

  1. Initial program 58.7

    \[\frac{1}{2} \cdot \log \left(\frac{1 + x}{1 - x}\right)\]

  2. Taylor expanded around 0 0.2

    \[\leadsto \frac{1}{2} \cdot \color{blue}{\left(\frac{2}{3} \cdot {x}^{3} + \left(\frac{2}{5} \cdot {x}^{5} + 2 \cdot x\right)\right)}\]

  3. Applied simplify0.2

    \[\leadsto \color{blue}{\left(\left(\frac{1}{3} \cdot x\right) \cdot \left(x \cdot x\right) + {x}^{5} \cdot \frac{1}{5}\right) + x}\]

Runtime

Time bar (total: 36.5s)Debug logProfile

herbie shell --seed '#(1071373924 2949776965 1885069702 3247780810 90874544 2263903749)' 
(FPCore (x)
  :name "Hyperbolic arc-(co)tangent"
  (* (/ 1 2) (log (/ (+ 1 x) (- 1 x)))))