Average Error: 40.4 → 0.5
Time: 9.0s
Precision: 64
Internal Precision: 1344
\[\frac{e^{x}}{e^{x} - 1}\]
\[\begin{array}{l} \mathbf{if}\;x \le -0.0018546157771360632:\\ \;\;\;\;\frac{e^{x}}{{\left(e^{x}\right)}^{3} - 1} \cdot \left(\left(e^{x} + 1\right) + e^{x + x}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{1}{2} + \frac{1}{x}\right) + \sqrt[3]{x \cdot \frac{1}{12}} \cdot {e}^{\left(\log \left(\sqrt[3]{x \cdot \frac{1}{12}} \cdot \sqrt[3]{x \cdot \frac{1}{12}}\right)\right)}\\ \end{array}\]

Error

Bits error versus x

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original40.4
Target40.0
Herbie0.5
\[\frac{1}{1 - e^{-x}}\]

Derivation

  1. Split input into 2 regimes
  2. if x < -0.0018546157771360632

    1. Initial program 0.0

      \[\frac{e^{x}}{e^{x} - 1}\]
    2. Using strategy rm
    3. Applied flip3--0.0

      \[\leadsto \frac{e^{x}}{\color{blue}{\frac{{\left(e^{x}\right)}^{3} - {1}^{3}}{e^{x} \cdot e^{x} + \left(1 \cdot 1 + e^{x} \cdot 1\right)}}}\]
    4. Applied associate-/r/0.0

      \[\leadsto \color{blue}{\frac{e^{x}}{{\left(e^{x}\right)}^{3} - {1}^{3}} \cdot \left(e^{x} \cdot e^{x} + \left(1 \cdot 1 + e^{x} \cdot 1\right)\right)}\]
    5. Simplified0.0

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

    if -0.0018546157771360632 < x

    1. Initial program 60.3

      \[\frac{e^{x}}{e^{x} - 1}\]
    2. Taylor expanded around 0 0.8

      \[\leadsto \color{blue}{\frac{1}{12} \cdot x + \left(\frac{1}{x} + \frac{1}{2}\right)}\]
    3. Using strategy rm
    4. Applied add-cube-cbrt0.8

      \[\leadsto \color{blue}{\left(\sqrt[3]{\frac{1}{12} \cdot x} \cdot \sqrt[3]{\frac{1}{12} \cdot x}\right) \cdot \sqrt[3]{\frac{1}{12} \cdot x}} + \left(\frac{1}{x} + \frac{1}{2}\right)\]
    5. Using strategy rm
    6. Applied add-exp-log0.8

      \[\leadsto \color{blue}{e^{\log \left(\sqrt[3]{\frac{1}{12} \cdot x} \cdot \sqrt[3]{\frac{1}{12} \cdot x}\right)}} \cdot \sqrt[3]{\frac{1}{12} \cdot x} + \left(\frac{1}{x} + \frac{1}{2}\right)\]
    7. Using strategy rm
    8. Applied *-un-lft-identity0.8

      \[\leadsto e^{\color{blue}{1 \cdot \log \left(\sqrt[3]{\frac{1}{12} \cdot x} \cdot \sqrt[3]{\frac{1}{12} \cdot x}\right)}} \cdot \sqrt[3]{\frac{1}{12} \cdot x} + \left(\frac{1}{x} + \frac{1}{2}\right)\]
    9. Applied exp-prod0.8

      \[\leadsto \color{blue}{{\left(e^{1}\right)}^{\left(\log \left(\sqrt[3]{\frac{1}{12} \cdot x} \cdot \sqrt[3]{\frac{1}{12} \cdot x}\right)\right)}} \cdot \sqrt[3]{\frac{1}{12} \cdot x} + \left(\frac{1}{x} + \frac{1}{2}\right)\]
    10. Simplified0.8

      \[\leadsto {\color{blue}{e}}^{\left(\log \left(\sqrt[3]{\frac{1}{12} \cdot x} \cdot \sqrt[3]{\frac{1}{12} \cdot x}\right)\right)} \cdot \sqrt[3]{\frac{1}{12} \cdot x} + \left(\frac{1}{x} + \frac{1}{2}\right)\]
  3. Recombined 2 regimes into one program.
  4. Final simplification0.5

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \le -0.0018546157771360632:\\ \;\;\;\;\frac{e^{x}}{{\left(e^{x}\right)}^{3} - 1} \cdot \left(\left(e^{x} + 1\right) + e^{x + x}\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{1}{2} + \frac{1}{x}\right) + \sqrt[3]{x \cdot \frac{1}{12}} \cdot {e}^{\left(\log \left(\sqrt[3]{x \cdot \frac{1}{12}} \cdot \sqrt[3]{x \cdot \frac{1}{12}}\right)\right)}\\ \end{array}\]

Runtime

Time bar (total: 9.0s)Debug logProfile

BaselineHerbieOracleSpan%
Regimes21.10.50.420.799.2%
herbie shell --seed 2018297 
(FPCore (x)
  :name "expq2 (section 3.11)"

  :herbie-target
  (/ 1 (- 1 (exp (- x))))

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