Average Error: 44.5 → 8.0
Time: 44.2s
Precision: 64
Internal Precision: 2368
\[(x \cdot y + z)_* - \left(1 + \left(x \cdot y + z\right)\right)\]
\[\begin{array}{l} \mathbf{if}\;\log \left(e^{\log \left(e^{\left(\left((x \cdot y + z)_* - z\right) - y \cdot x\right) - 1}\right)}\right) \le -1.0000000000757885:\\ \;\;\;\;\log \left(e^{\left(\left((x \cdot y + z)_* - y \cdot x\right) - z\right) - 1}\right)\\ \mathbf{elif}\;\log \left(e^{\log \left(e^{\left(\left((x \cdot y + z)_* - z\right) - y \cdot x\right) - 1}\right)}\right) \le -0.9999999999999986:\\ \;\;\;\;\log \left(e^{\log \left(e^{\left(\left((x \cdot y + z)_* - z\right) - y \cdot x\right) - 1}\right)}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(e^{\left(\left((x \cdot y + z)_* - y \cdot x\right) - z\right) - 1}\right)\\ \end{array}\]

Error

Bits error versus x

Bits error versus y

Bits error versus z

Target

Original44.5
Target0
Herbie8.0
\[-1\]

Derivation

  1. Split input into 2 regimes
  2. if (log (exp (log (exp (- (- (- (fma x y z) z) (* y x)) 1))))) < -1.0000000000757885 or -0.9999999999999986 < (log (exp (log (exp (- (- (- (fma x y z) z) (* y x)) 1)))))

    1. Initial program 62.7

      \[(x \cdot y + z)_* - \left(1 + \left(x \cdot y + z\right)\right)\]
    2. Using strategy rm
    3. Applied add-log-exp63.2

      \[\leadsto (x \cdot y + z)_* - \color{blue}{\log \left(e^{1 + \left(x \cdot y + z\right)}\right)}\]
    4. Applied add-log-exp63.6

      \[\leadsto \color{blue}{\log \left(e^{(x \cdot y + z)_*}\right)} - \log \left(e^{1 + \left(x \cdot y + z\right)}\right)\]
    5. Applied diff-log63.6

      \[\leadsto \color{blue}{\log \left(\frac{e^{(x \cdot y + z)_*}}{e^{1 + \left(x \cdot y + z\right)}}\right)}\]
    6. Applied simplify62.7

      \[\leadsto \log \color{blue}{\left(e^{\left((x \cdot y + z)_* - y \cdot x\right) - \left(z + 1\right)}\right)}\]
    7. Using strategy rm
    8. Applied associate--r+33.7

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

    if -1.0000000000757885 < (log (exp (log (exp (- (- (- (fma x y z) z) (* y x)) 1))))) < -0.9999999999999986

    1. Initial program 38.9

      \[(x \cdot y + z)_* - \left(1 + \left(x \cdot y + z\right)\right)\]
    2. Using strategy rm
    3. Applied add-log-exp41.1

      \[\leadsto (x \cdot y + z)_* - \color{blue}{\log \left(e^{1 + \left(x \cdot y + z\right)}\right)}\]
    4. Applied add-log-exp41.6

      \[\leadsto \color{blue}{\log \left(e^{(x \cdot y + z)_*}\right)} - \log \left(e^{1 + \left(x \cdot y + z\right)}\right)\]
    5. Applied diff-log41.7

      \[\leadsto \color{blue}{\log \left(\frac{e^{(x \cdot y + z)_*}}{e^{1 + \left(x \cdot y + z\right)}}\right)}\]
    6. Applied simplify25.1

      \[\leadsto \log \color{blue}{\left(e^{\left((x \cdot y + z)_* - y \cdot x\right) - \left(z + 1\right)}\right)}\]
    7. Using strategy rm
    8. Applied add-log-exp26.2

      \[\leadsto \log \left(e^{\left((x \cdot y + z)_* - y \cdot x\right) - \color{blue}{\log \left(e^{z + 1}\right)}}\right)\]
    9. Applied add-log-exp41.2

      \[\leadsto \log \left(e^{\left((x \cdot y + z)_* - \color{blue}{\log \left(e^{y \cdot x}\right)}\right) - \log \left(e^{z + 1}\right)}\right)\]
    10. Applied add-log-exp41.6

      \[\leadsto \log \left(e^{\left(\color{blue}{\log \left(e^{(x \cdot y + z)_*}\right)} - \log \left(e^{y \cdot x}\right)\right) - \log \left(e^{z + 1}\right)}\right)\]
    11. Applied diff-log41.6

      \[\leadsto \log \left(e^{\color{blue}{\log \left(\frac{e^{(x \cdot y + z)_*}}{e^{y \cdot x}}\right)} - \log \left(e^{z + 1}\right)}\right)\]
    12. Applied diff-log41.6

      \[\leadsto \log \left(e^{\color{blue}{\log \left(\frac{\frac{e^{(x \cdot y + z)_*}}{e^{y \cdot x}}}{e^{z + 1}}\right)}}\right)\]
    13. Applied simplify21.0

      \[\leadsto \log \left(e^{\log \color{blue}{\left(e^{\left((x \cdot y + z)_* - z\right) - \left(y \cdot x + 1\right)}\right)}}\right)\]
    14. Using strategy rm
    15. Applied associate--r+0.0

      \[\leadsto \log \left(e^{\log \left(e^{\color{blue}{\left(\left((x \cdot y + z)_* - z\right) - y \cdot x\right) - 1}}\right)}\right)\]
  3. Recombined 2 regimes into one program.

Runtime

Time bar (total: 44.2s)Debug logProfile

herbie shell --seed 2018208 
(FPCore (x y z)
  :name "simple fma test"

  :herbie-target
  -1

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