Average Error: 20.4 → 0.0
Time: 27.4s
Precision: 64
Internal Precision: 128
\[\frac{\left(x - y\right) \cdot \left(x + y\right)}{x \cdot x + y \cdot y}\]
\[\log_* (1 + (e^{\frac{\frac{x - y}{\sqrt{x^2 + y^2}^*} \cdot x + y \cdot \frac{x - y}{\sqrt{x^2 + y^2}^*}}{\sqrt{x^2 + y^2}^*}} - 1)^*)\]

Error

Bits error versus x

Bits error versus y

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Your Program's Arguments

Results

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Target

Original20.4
Target0.1
Herbie0.0
\[\begin{array}{l} \mathbf{if}\;0.5 \lt \left|\frac{x}{y}\right| \lt 2:\\ \;\;\;\;\frac{\left(x - y\right) \cdot \left(x + y\right)}{x \cdot x + y \cdot y}\\ \mathbf{else}:\\ \;\;\;\;1 - \frac{2}{1 + \frac{x}{y} \cdot \frac{x}{y}}\\ \end{array}\]

Derivation

  1. Initial program 20.4

    \[\frac{\left(x - y\right) \cdot \left(x + y\right)}{x \cdot x + y \cdot y}\]
  2. Initial simplification20.4

    \[\leadsto \frac{\left(x - y\right) \cdot \left(y + x\right)}{(x \cdot x + \left(y \cdot y\right))_*}\]
  3. Using strategy rm
  4. Applied add-sqr-sqrt20.4

    \[\leadsto \frac{\left(x - y\right) \cdot \left(y + x\right)}{\color{blue}{\sqrt{(x \cdot x + \left(y \cdot y\right))_*} \cdot \sqrt{(x \cdot x + \left(y \cdot y\right))_*}}}\]
  5. Applied times-frac20.4

    \[\leadsto \color{blue}{\frac{x - y}{\sqrt{(x \cdot x + \left(y \cdot y\right))_*}} \cdot \frac{y + x}{\sqrt{(x \cdot x + \left(y \cdot y\right))_*}}}\]
  6. Simplified20.4

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

    \[\leadsto \frac{x - y}{\sqrt{x^2 + y^2}^*} \cdot \color{blue}{\frac{x + y}{\sqrt{x^2 + y^2}^*}}\]
  8. Using strategy rm
  9. Applied associate-*r/0.0

    \[\leadsto \color{blue}{\frac{\frac{x - y}{\sqrt{x^2 + y^2}^*} \cdot \left(x + y\right)}{\sqrt{x^2 + y^2}^*}}\]
  10. Using strategy rm
  11. Applied distribute-lft-in0.0

    \[\leadsto \frac{\color{blue}{\frac{x - y}{\sqrt{x^2 + y^2}^*} \cdot x + \frac{x - y}{\sqrt{x^2 + y^2}^*} \cdot y}}{\sqrt{x^2 + y^2}^*}\]
  12. Using strategy rm
  13. Applied log1p-expm1-u0.0

    \[\leadsto \color{blue}{\log_* (1 + (e^{\frac{\frac{x - y}{\sqrt{x^2 + y^2}^*} \cdot x + \frac{x - y}{\sqrt{x^2 + y^2}^*} \cdot y}{\sqrt{x^2 + y^2}^*}} - 1)^*)}\]
  14. Final simplification0.0

    \[\leadsto \log_* (1 + (e^{\frac{\frac{x - y}{\sqrt{x^2 + y^2}^*} \cdot x + y \cdot \frac{x - y}{\sqrt{x^2 + y^2}^*}}{\sqrt{x^2 + y^2}^*}} - 1)^*)\]

Runtime

Time bar (total: 27.4s)Debug logProfile

BaselineHerbieOracleSpan%
Regimes0.00.00.00.00%
herbie shell --seed 2018352 +o rules:numerics
(FPCore (x y)
  :name "Kahan p9 Example"
  :pre (and (< 0 x 1) (< y 1))

  :herbie-target
  (if (< 0.5 (fabs (/ x y)) 2) (/ (* (- x y) (+ x y)) (+ (* x x) (* y y))) (- 1 (/ 2 (+ 1 (* (/ x y) (/ x y))))))

  (/ (* (- x y) (+ x y)) (+ (* x x) (* y y))))