Average Error: 29.5 → 0.0
Time: 1.2m
Precision: 64
Internal Precision: 1344
\[\frac{x}{x + 1} - \frac{x + 1}{x - 1}\]
\[\begin{array}{l} \mathbf{if}\;x \le -7533157453258729.0 \lor \neg \left(x \le 116650.87853212819\right):\\ \;\;\;\;(\left(\frac{-1}{x \cdot x}\right) \cdot \left(\frac{3}{x}\right) + \left(\frac{-1}{x \cdot x} - \frac{3}{x}\right))_*\\ \mathbf{else}:\\ \;\;\;\;\frac{-3 \cdot x + -1}{(x \cdot x + -1)_*}\\ \end{array}\]

Error

Bits error versus x

Derivation

  1. Split input into 2 regimes
  2. if x < -7533157453258729.0 or 116650.87853212819 < x

    1. Initial program 59.9

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1}\]
    2. Taylor expanded around inf 0.3

      \[\leadsto \color{blue}{-\left(3 \cdot \frac{1}{{x}^{3}} + \left(\frac{1}{{x}^{2}} + 3 \cdot \frac{1}{x}\right)\right)}\]
    3. Simplified0.0

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

    if -7533157453258729.0 < x < 116650.87853212819

    1. Initial program 0.6

      \[\frac{x}{x + 1} - \frac{x + 1}{x - 1}\]
    2. Using strategy rm
    3. Applied add-cube-cbrt0.7

      \[\leadsto \frac{x}{x + 1} - \frac{x + 1}{\color{blue}{\left(\sqrt[3]{x - 1} \cdot \sqrt[3]{x - 1}\right) \cdot \sqrt[3]{x - 1}}}\]
    4. Applied *-un-lft-identity0.7

      \[\leadsto \frac{x}{x + 1} - \frac{\color{blue}{1 \cdot \left(x + 1\right)}}{\left(\sqrt[3]{x - 1} \cdot \sqrt[3]{x - 1}\right) \cdot \sqrt[3]{x - 1}}\]
    5. Applied times-frac0.7

      \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{1}{\sqrt[3]{x - 1} \cdot \sqrt[3]{x - 1}} \cdot \frac{x + 1}{\sqrt[3]{x - 1}}}\]
    6. Using strategy rm
    7. Applied frac-times0.7

      \[\leadsto \frac{x}{x + 1} - \color{blue}{\frac{1 \cdot \left(x + 1\right)}{\left(\sqrt[3]{x - 1} \cdot \sqrt[3]{x - 1}\right) \cdot \sqrt[3]{x - 1}}}\]
    8. Applied frac-sub0.7

      \[\leadsto \color{blue}{\frac{x \cdot \left(\left(\sqrt[3]{x - 1} \cdot \sqrt[3]{x - 1}\right) \cdot \sqrt[3]{x - 1}\right) - \left(x + 1\right) \cdot \left(1 \cdot \left(x + 1\right)\right)}{\left(x + 1\right) \cdot \left(\left(\sqrt[3]{x - 1} \cdot \sqrt[3]{x - 1}\right) \cdot \sqrt[3]{x - 1}\right)}}\]
    9. Simplified0.1

      \[\leadsto \frac{\color{blue}{(x \cdot \left(x - \left(x + 2\right)\right) + \left(-1 - x\right))_*}}{\left(x + 1\right) \cdot \left(\left(\sqrt[3]{x - 1} \cdot \sqrt[3]{x - 1}\right) \cdot \sqrt[3]{x - 1}\right)}\]
    10. Simplified0.0

      \[\leadsto \frac{(x \cdot \left(x - \left(x + 2\right)\right) + \left(-1 - x\right))_*}{\color{blue}{(x \cdot \left(-1 + x\right) + \left(-1 + x\right))_*}}\]
    11. Using strategy rm
    12. Applied *-un-lft-identity0.0

      \[\leadsto \frac{(x \cdot \left(x - \left(x + 2\right)\right) + \left(-1 - x\right))_*}{\color{blue}{1 \cdot (x \cdot \left(-1 + x\right) + \left(-1 + x\right))_*}}\]
    13. Applied *-un-lft-identity0.0

      \[\leadsto \frac{\color{blue}{1 \cdot (x \cdot \left(x - \left(x + 2\right)\right) + \left(-1 - x\right))_*}}{1 \cdot (x \cdot \left(-1 + x\right) + \left(-1 + x\right))_*}\]
    14. Applied times-frac0.0

      \[\leadsto \color{blue}{\frac{1}{1} \cdot \frac{(x \cdot \left(x - \left(x + 2\right)\right) + \left(-1 - x\right))_*}{(x \cdot \left(-1 + x\right) + \left(-1 + x\right))_*}}\]
    15. Simplified0.0

      \[\leadsto \color{blue}{1} \cdot \frac{(x \cdot \left(x - \left(x + 2\right)\right) + \left(-1 - x\right))_*}{(x \cdot \left(-1 + x\right) + \left(-1 + x\right))_*}\]
    16. Simplified0.0

      \[\leadsto 1 \cdot \color{blue}{\frac{x \cdot -3 + -1}{(x \cdot x + -1)_*}}\]
  3. Recombined 2 regimes into one program.
  4. Final simplification0.0

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \le -7533157453258729.0 \lor \neg \left(x \le 116650.87853212819\right):\\ \;\;\;\;(\left(\frac{-1}{x \cdot x}\right) \cdot \left(\frac{3}{x}\right) + \left(\frac{-1}{x \cdot x} - \frac{3}{x}\right))_*\\ \mathbf{else}:\\ \;\;\;\;\frac{-3 \cdot x + -1}{(x \cdot x + -1)_*}\\ \end{array}\]

Runtime

Time bar (total: 1.2m)Debug logProfile

BaselineHerbieOracleSpan%
Regimes15.20.00.015.2100%
herbie shell --seed 2018285 +o rules:numerics
(FPCore (x)
  :name "Asymptote C"
  (- (/ x (+ x 1)) (/ (+ x 1) (- x 1))))