Average Error: 0.6 → 0.6
Time: 22.6s
Precision: 64
Internal Precision: 576
\[\log \left(1 + e^{x}\right) - x \cdot y\]
\[\left(\log \left(\sqrt{{\left(e^{x}\right)}^{3} + 1}\right) + \left(\log \left(\sqrt{\sqrt{{\left(e^{x}\right)}^{3} + 1}}\right) + \log \left(\sqrt{\sqrt{{\left(e^{x}\right)}^{3} + 1}}\right)\right)\right) - \left(\log \left(1 + \left(e^{x} \cdot e^{x} - e^{x}\right)\right) + x \cdot y\right)\]

Error

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Bits error versus y

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Results

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Target

Original0.6
Target0.1
Herbie0.6
\[\begin{array}{l} \mathbf{if}\;x \le 0:\\ \;\;\;\;\log \left(1 + e^{x}\right) - x \cdot y\\ \mathbf{else}:\\ \;\;\;\;\log \left(1 + e^{-x}\right) - \left(-x\right) \cdot \left(1 - y\right)\\ \end{array}\]

Derivation

  1. Initial program 0.6

    \[\log \left(1 + e^{x}\right) - x \cdot y\]
  2. Initial simplification0.6

    \[\leadsto \log \left(1 + e^{x}\right) - y \cdot x\]
  3. Using strategy rm
  4. Applied flip3-+0.6

    \[\leadsto \log \color{blue}{\left(\frac{{1}^{3} + {\left(e^{x}\right)}^{3}}{1 \cdot 1 + \left(e^{x} \cdot e^{x} - 1 \cdot e^{x}\right)}\right)} - y \cdot x\]
  5. Applied log-div0.6

    \[\leadsto \color{blue}{\left(\log \left({1}^{3} + {\left(e^{x}\right)}^{3}\right) - \log \left(1 \cdot 1 + \left(e^{x} \cdot e^{x} - 1 \cdot e^{x}\right)\right)\right)} - y \cdot x\]
  6. Applied associate--l-0.6

    \[\leadsto \color{blue}{\log \left({1}^{3} + {\left(e^{x}\right)}^{3}\right) - \left(\log \left(1 \cdot 1 + \left(e^{x} \cdot e^{x} - 1 \cdot e^{x}\right)\right) + y \cdot x\right)}\]
  7. Simplified0.6

    \[\leadsto \color{blue}{\log \left({\left(e^{x}\right)}^{3} + 1\right)} - \left(\log \left(1 \cdot 1 + \left(e^{x} \cdot e^{x} - 1 \cdot e^{x}\right)\right) + y \cdot x\right)\]
  8. Using strategy rm
  9. Applied add-sqr-sqrt1.4

    \[\leadsto \log \color{blue}{\left(\sqrt{{\left(e^{x}\right)}^{3} + 1} \cdot \sqrt{{\left(e^{x}\right)}^{3} + 1}\right)} - \left(\log \left(1 \cdot 1 + \left(e^{x} \cdot e^{x} - 1 \cdot e^{x}\right)\right) + y \cdot x\right)\]
  10. Applied log-prod1.1

    \[\leadsto \color{blue}{\left(\log \left(\sqrt{{\left(e^{x}\right)}^{3} + 1}\right) + \log \left(\sqrt{{\left(e^{x}\right)}^{3} + 1}\right)\right)} - \left(\log \left(1 \cdot 1 + \left(e^{x} \cdot e^{x} - 1 \cdot e^{x}\right)\right) + y \cdot x\right)\]
  11. Using strategy rm
  12. Applied add-sqr-sqrt1.1

    \[\leadsto \left(\log \left(\sqrt{{\left(e^{x}\right)}^{3} + 1}\right) + \log \left(\sqrt{\color{blue}{\sqrt{{\left(e^{x}\right)}^{3} + 1} \cdot \sqrt{{\left(e^{x}\right)}^{3} + 1}}}\right)\right) - \left(\log \left(1 \cdot 1 + \left(e^{x} \cdot e^{x} - 1 \cdot e^{x}\right)\right) + y \cdot x\right)\]
  13. Applied sqrt-prod0.6

    \[\leadsto \left(\log \left(\sqrt{{\left(e^{x}\right)}^{3} + 1}\right) + \log \color{blue}{\left(\sqrt{\sqrt{{\left(e^{x}\right)}^{3} + 1}} \cdot \sqrt{\sqrt{{\left(e^{x}\right)}^{3} + 1}}\right)}\right) - \left(\log \left(1 \cdot 1 + \left(e^{x} \cdot e^{x} - 1 \cdot e^{x}\right)\right) + y \cdot x\right)\]
  14. Applied log-prod0.6

    \[\leadsto \left(\log \left(\sqrt{{\left(e^{x}\right)}^{3} + 1}\right) + \color{blue}{\left(\log \left(\sqrt{\sqrt{{\left(e^{x}\right)}^{3} + 1}}\right) + \log \left(\sqrt{\sqrt{{\left(e^{x}\right)}^{3} + 1}}\right)\right)}\right) - \left(\log \left(1 \cdot 1 + \left(e^{x} \cdot e^{x} - 1 \cdot e^{x}\right)\right) + y \cdot x\right)\]
  15. Final simplification0.6

    \[\leadsto \left(\log \left(\sqrt{{\left(e^{x}\right)}^{3} + 1}\right) + \left(\log \left(\sqrt{\sqrt{{\left(e^{x}\right)}^{3} + 1}}\right) + \log \left(\sqrt{\sqrt{{\left(e^{x}\right)}^{3} + 1}}\right)\right)\right) - \left(\log \left(1 + \left(e^{x} \cdot e^{x} - e^{x}\right)\right) + x \cdot y\right)\]

Runtime

Time bar (total: 22.6s)Debug logProfile

herbie shell --seed 2018250 
(FPCore (x y)
  :name "Logistic regression 2"

  :herbie-target
  (if (<= x 0) (- (log (+ 1 (exp x))) (* x y)) (- (log (+ 1 (exp (- x)))) (* (- x) (- 1 y))))

  (- (log (+ 1 (exp x))) (* x y)))