Average Error: 15.0 → 0.0
Time: 30.1s
Precision: 64
Internal Precision: 384
\[\frac{x}{x \cdot x + 1}\]
\[\begin{array}{l} \mathbf{if}\;x \le -5794719.831835442:\\ \;\;\;\;\left(\frac{1}{{x}^{5}} + \frac{1}{x}\right) - \frac{1}{{x}^{3}}\\ \mathbf{if}\;x \le 243137.8576605884:\\ \;\;\;\;\left(\left(1 - x \cdot x\right) + \left(x \cdot x\right) \cdot \left(x \cdot x\right)\right) \cdot \frac{x}{(\left({x}^{3}\right) \cdot \left({x}^{3}\right) + 1)_*}\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{1}{{x}^{5}} + \frac{1}{x}\right) - \frac{1}{{x}^{3}}\\ \end{array}\]

Error

Bits error versus x

Target

Original15.0
Target0.1
Herbie0.0
\[\frac{1}{x + \frac{1}{x}}\]

Derivation

  1. Split input into 2 regimes
  2. if x < -5794719.831835442 or 243137.8576605884 < x

    1. Initial program 30.6

      \[\frac{x}{x \cdot x + 1}\]
    2. Taylor expanded around inf 0.0

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

    if -5794719.831835442 < x < 243137.8576605884

    1. Initial program 0.0

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

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

      \[\leadsto \color{blue}{\frac{x}{{\left(x \cdot x\right)}^{3} + {1}^{3}} \cdot \left(\left(x \cdot x\right) \cdot \left(x \cdot x\right) + \left(1 \cdot 1 - \left(x \cdot x\right) \cdot 1\right)\right)}\]
    5. Applied simplify0.0

      \[\leadsto \color{blue}{\frac{x}{(\left({x}^{3}\right) \cdot \left({x}^{3}\right) + 1)_*}} \cdot \left(\left(x \cdot x\right) \cdot \left(x \cdot x\right) + \left(1 \cdot 1 - \left(x \cdot x\right) \cdot 1\right)\right)\]
  3. Recombined 2 regimes into one program.
  4. Applied simplify0.0

    \[\leadsto \color{blue}{\begin{array}{l} \mathbf{if}\;x \le -5794719.831835442:\\ \;\;\;\;\left(\frac{1}{{x}^{5}} + \frac{1}{x}\right) - \frac{1}{{x}^{3}}\\ \mathbf{if}\;x \le 243137.8576605884:\\ \;\;\;\;\left(\left(1 - x \cdot x\right) + \left(x \cdot x\right) \cdot \left(x \cdot x\right)\right) \cdot \frac{x}{(\left({x}^{3}\right) \cdot \left({x}^{3}\right) + 1)_*}\\ \mathbf{else}:\\ \;\;\;\;\left(\frac{1}{{x}^{5}} + \frac{1}{x}\right) - \frac{1}{{x}^{3}}\\ \end{array}}\]

Runtime

Time bar (total: 30.1s)Debug logProfile

herbie shell --seed '#(1064173506 2580572819 2847706409 4129882574 1125180799 1845288547)' +o rules:numerics
(FPCore (x)
  :name "x / (x^2 + 1)"

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

  (/ x (+ (* x x) 1)))