Average Error: 45.3 → 7.8
Time: 18.8s
Precision: 64
Internal Precision: 2368
\[(x \cdot y + z)_* - \left(1 + \left(x \cdot y + z\right)\right)\]
\[\log \left(e^{-1 - \left(\left(y \cdot x + z\right) - (x \cdot y + z)_*\right)}\right)\]

Error

Bits error versus x

Bits error versus y

Bits error versus z

Target

Original45.3
Target0
Herbie7.8
\[-1\]

Derivation

  1. Initial program 45.3

    \[(x \cdot y + z)_* - \left(1 + \left(x \cdot y + z\right)\right)\]
  2. Initial simplification45.3

    \[\leadsto (x \cdot y + z)_* + \left(\left(-1 - z\right) - x \cdot y\right)\]
  3. Using strategy rm
  4. Applied add-log-exp46.2

    \[\leadsto (x \cdot y + z)_* + \left(\left(-1 - z\right) - \color{blue}{\log \left(e^{x \cdot y}\right)}\right)\]
  5. Applied add-log-exp47.1

    \[\leadsto (x \cdot y + z)_* + \left(\color{blue}{\log \left(e^{-1 - z}\right)} - \log \left(e^{x \cdot y}\right)\right)\]
  6. Applied diff-log47.1

    \[\leadsto (x \cdot y + z)_* + \color{blue}{\log \left(\frac{e^{-1 - z}}{e^{x \cdot y}}\right)}\]
  7. Applied add-log-exp47.5

    \[\leadsto \color{blue}{\log \left(e^{(x \cdot y + z)_*}\right)} + \log \left(\frac{e^{-1 - z}}{e^{x \cdot y}}\right)\]
  8. Applied sum-log47.5

    \[\leadsto \color{blue}{\log \left(e^{(x \cdot y + z)_*} \cdot \frac{e^{-1 - z}}{e^{x \cdot y}}\right)}\]
  9. Simplified31.0

    \[\leadsto \log \color{blue}{\left(e^{\left(-1 - x \cdot y\right) - \left(z - (x \cdot y + z)_*\right)}\right)}\]
  10. Using strategy rm
  11. Applied associate--l-14.9

    \[\leadsto \log \left(e^{\color{blue}{-1 - \left(x \cdot y + \left(z - (x \cdot y + z)_*\right)\right)}}\right)\]
  12. Using strategy rm
  13. Applied associate-+r-7.8

    \[\leadsto \log \left(e^{-1 - \color{blue}{\left(\left(x \cdot y + z\right) - (x \cdot y + z)_*\right)}}\right)\]
  14. Final simplification7.8

    \[\leadsto \log \left(e^{-1 - \left(\left(y \cdot x + z\right) - (x \cdot y + z)_*\right)}\right)\]

Runtime

Time bar (total: 18.8s)Debug logProfile

herbie shell --seed 2018234 
(FPCore (x y z)
  :name "simple fma test"

  :herbie-target
  -1

  (- (fma x y z) (+ 1 (+ (* x y) z))))