Average Error: 40.0 → 0.3
Time: 27.7s
Precision: 64
Internal Precision: 1408
\[\frac{e^{x} - 1}{x}\]
\[\begin{array}{l} \mathbf{if}\;x \le -0.00014688974838714762:\\ \;\;\;\;\frac{\frac{{\left(e^{2}\right)}^{\left(x + x\right)} - 1}{\left(e^{x} \cdot e^{x} - 1\right) \cdot \left(e^{x} \cdot e^{x} + 1\right)} \cdot \left(e^{x} - 1\right)}{x}\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{6} \cdot {x}^{2} + \left(1 + \frac{1}{2} \cdot x\right)\\ \end{array}\]

Error

Bits error versus x

Target

Original40.0
Target39.1
Herbie0.3
\[\begin{array}{l} \mathbf{if}\;x \lt 1 \land x \gt -1:\\ \;\;\;\;\frac{e^{x} - 1}{\log \left(e^{x}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{e^{x} - 1}{x}\\ \end{array}\]

Derivation

  1. Split input into 2 regimes
  2. if x < -0.00014688974838714762

    1. Initial program 0.1

      \[\frac{e^{x} - 1}{x}\]
    2. Using strategy rm
    3. Applied flip--0.1

      \[\leadsto \frac{\color{blue}{\frac{e^{x} \cdot e^{x} - 1 \cdot 1}{e^{x} + 1}}}{x}\]
    4. Applied simplify0.0

      \[\leadsto \frac{\frac{\color{blue}{e^{x + x} - 1}}{e^{x} + 1}}{x}\]
    5. Using strategy rm
    6. Applied flip--0.1

      \[\leadsto \frac{\frac{\color{blue}{\frac{e^{x + x} \cdot e^{x + x} - 1 \cdot 1}{e^{x + x} + 1}}}{e^{x} + 1}}{x}\]
    7. Applied simplify0.0

      \[\leadsto \frac{\frac{\frac{\color{blue}{{\left(e^{2}\right)}^{\left(x + x\right)} - 1}}{e^{x + x} + 1}}{e^{x} + 1}}{x}\]
    8. Using strategy rm
    9. Applied flip-+0.0

      \[\leadsto \frac{\frac{\frac{{\left(e^{2}\right)}^{\left(x + x\right)} - 1}{e^{x + x} + 1}}{\color{blue}{\frac{e^{x} \cdot e^{x} - 1 \cdot 1}{e^{x} - 1}}}}{x}\]
    10. Applied associate-/r/0.0

      \[\leadsto \frac{\color{blue}{\frac{\frac{{\left(e^{2}\right)}^{\left(x + x\right)} - 1}{e^{x + x} + 1}}{e^{x} \cdot e^{x} - 1 \cdot 1} \cdot \left(e^{x} - 1\right)}}{x}\]
    11. Applied simplify0.0

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

    if -0.00014688974838714762 < x

    1. Initial program 60.1

      \[\frac{e^{x} - 1}{x}\]
    2. Taylor expanded around 0 0.4

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

Runtime

Time bar (total: 27.7s)Debug logProfile

herbie shell --seed '#(1064397287 3527694221 3797617954 1138343853 2854031332 1153838279)' 
(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))