Average Error: 39.9 → 0.4
Time: 15.2s
Precision: 64
Internal Precision: 128
\[\frac{e^{x} - 1}{x}\]
↓
\[\begin{array}{l} \mathbf{if}\;x \le -0.00013237463699387517:\\ \;\;\;\;\frac{\log \left(e^{-1 + e^{x}}\right)}{x}\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{1}{6} \cdot x + \left(\frac{1}{36} \cdot {x}^{2} + 1\right)\right) \cdot \left(\left(\frac{1}{6} \cdot x + \left(\frac{1}{36} \cdot {x}^{2} + 1\right)\right) \cdot \sqrt[3]{\left(1 + \frac{1}{6} \cdot {x}^{2}\right) + x \cdot \frac{1}{2}}\right)\\ \end{array}\]

Error

Bits error versus x

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original39.9
Target39.0
Herbie0.4
\[\begin{array}{l} \mathbf{if}\;x \lt 1 \land x \gt -1:\\ \;\;\;\;\frac{e^{x} - 1}{\log \left(e^{x}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{e^{x} - 1}{x}\\ \end{array}\]

Derivation

  1. Split input into 2 regimes

  2. if x < -0.00013237463699387517

    1. Initial program 0.0

      \[\frac{e^{x} - 1}{x}\]

    2. Initial simplification0.0

      \[\leadsto \frac{-1 + e^{x}}{x}\]
    3. Using strategy rm

    4. Applied add-log-exp0.0

      \[\leadsto \frac{\color{blue}{\log \left(e^{-1 + e^{x}}\right)}}{x}\]

    if -0.00013237463699387517 < x

    1. Initial program 59.9

      \[\frac{e^{x} - 1}{x}\]

    2. Initial simplification59.9

      \[\leadsto \frac{-1 + e^{x}}{x}\]

    3. Taylor expanded around 0 0.6

      \[\leadsto \color{blue}{\frac{1}{2} \cdot x + \left(\frac{1}{6} \cdot {x}^{2} + 1\right)}\]
    4. Using strategy rm

    5. Applied add-cube-cbrt0.6

      \[\leadsto \color{blue}{\left(\sqrt[3]{\frac{1}{2} \cdot x + \left(\frac{1}{6} \cdot {x}^{2} + 1\right)} \cdot \sqrt[3]{\frac{1}{2} \cdot x + \left(\frac{1}{6} \cdot {x}^{2} + 1\right)}\right) \cdot \sqrt[3]{\frac{1}{2} \cdot x + \left(\frac{1}{6} \cdot {x}^{2} + 1\right)}}\]

    6. Taylor expanded around 0 0.6

      \[\leadsto \left(\color{blue}{\left(\frac{1}{6} \cdot x + \left(\frac{1}{36} \cdot {x}^{2} + 1\right)\right)} \cdot \sqrt[3]{\frac{1}{2} \cdot x + \left(\frac{1}{6} \cdot {x}^{2} + 1\right)}\right) \cdot \sqrt[3]{\frac{1}{2} \cdot x + \left(\frac{1}{6} \cdot {x}^{2} + 1\right)}\]

    7. Taylor expanded around 0 0.6

      \[\leadsto \left(\left(\frac{1}{6} \cdot x + \left(\frac{1}{36} \cdot {x}^{2} + 1\right)\right) \cdot \sqrt[3]{\frac{1}{2} \cdot x + \left(\frac{1}{6} \cdot {x}^{2} + 1\right)}\right) \cdot \color{blue}{\left(\frac{1}{6} \cdot x + \left(\frac{1}{36} \cdot {x}^{2} + 1\right)\right)}\]
  3. Recombined 2 regimes into one program.

  4. Final simplification0.4

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \le -0.00013237463699387517:\\ \;\;\;\;\frac{\log \left(e^{-1 + e^{x}}\right)}{x}\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{1}{6} \cdot x + \left(\frac{1}{36} \cdot {x}^{2} + 1\right)\right) \cdot \left(\left(\frac{1}{6} \cdot x + \left(\frac{1}{36} \cdot {x}^{2} + 1\right)\right) \cdot \sqrt[3]{\left(1 + \frac{1}{6} \cdot {x}^{2}\right) + x \cdot \frac{1}{2}}\right)\\ \end{array}\]

Runtime

Time bar (total: 15.2s)Debug logProfile

BaselineHerbieOracleSpan%
Regimes21.00.40.220.899.1%
herbie shell --seed 2018353 
(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))