Average Error: 40.8 → 40.8
Time: 10.7s
Precision: 64
Internal Precision: 128
\[\frac{e^{x} - 1}{x}\]
\[\frac{(\left(\sqrt{e^{x}}\right) \cdot \left(\sqrt[3]{\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}} \cdot \left(\sqrt[3]{\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}} \cdot \sqrt[3]{\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}}\right)\right) + -1)_*}{x}\]

Error

Bits error versus x

Target

Original40.8
Target62.2
Herbie40.8
\[\begin{array}{l} \mathbf{if}\;x \lt 1 \land x \gt -1:\\ \;\;\;\;\frac{e^{x} - 1}{\log \left(e^{x}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{e^{x} - 1}{x}\\ \end{array}\]

Derivation

  1. Initial program 40.8

    \[\frac{e^{x} - 1}{x}\]
  2. Using strategy rm
  3. Applied add-sqr-sqrt40.8

    \[\leadsto \frac{\color{blue}{\sqrt{e^{x}} \cdot \sqrt{e^{x}}} - 1}{x}\]
  4. Applied fma-neg40.8

    \[\leadsto \frac{\color{blue}{(\left(\sqrt{e^{x}}\right) \cdot \left(\sqrt{e^{x}}\right) + \left(-1\right))_*}}{x}\]
  5. Using strategy rm
  6. Applied add-sqr-sqrt40.8

    \[\leadsto \frac{(\left(\sqrt{e^{x}}\right) \cdot \left(\sqrt{\color{blue}{\sqrt{e^{x}} \cdot \sqrt{e^{x}}}}\right) + \left(-1\right))_*}{x}\]
  7. Applied sqrt-prod40.8

    \[\leadsto \frac{(\left(\sqrt{e^{x}}\right) \cdot \color{blue}{\left(\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}\right)} + \left(-1\right))_*}{x}\]
  8. Using strategy rm
  9. Applied add-cube-cbrt40.8

    \[\leadsto \frac{(\left(\sqrt{e^{x}}\right) \cdot \color{blue}{\left(\left(\sqrt[3]{\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}} \cdot \sqrt[3]{\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}}\right) \cdot \sqrt[3]{\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}}\right)} + \left(-1\right))_*}{x}\]
  10. Final simplification40.8

    \[\leadsto \frac{(\left(\sqrt{e^{x}}\right) \cdot \left(\sqrt[3]{\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}} \cdot \left(\sqrt[3]{\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}} \cdot \sqrt[3]{\sqrt{\sqrt{e^{x}}} \cdot \sqrt{\sqrt{e^{x}}}}\right)\right) + -1)_*}{x}\]

Runtime

Time bar (total: 10.7s)Debug logProfile

herbie shell --seed 2018255 +o rules:numerics
(FPCore (x)
  :name "Kahan's exp quotient"

  :herbie-target
  (if (and (< x 1) (> x -1)) (/ (- (exp x) 1) (log (exp x))) (/ (- (exp x) 1) x))

  (/ (- (exp x) 1) x))