Average Error: 13.9 → 13.9
Time: 1.3m
Precision: 64
Internal Precision: 384
\[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|}\]
\[1 - \frac{1}{\left|x\right| \cdot 0.3275911 + 1} \cdot \frac{e^{\log \left(\left(1.421413741 + \frac{-1.453152027}{\left|x\right| \cdot 0.3275911 + 1}\right) + \frac{\frac{1.061405429}{\left|x\right| \cdot 0.3275911 + 1}}{\left|x\right| \cdot 0.3275911 + 1}\right) - \left(\log \left(\left|x\right| \cdot 0.3275911 + 1\right) - \left(-\log \left(\left|x\right| \cdot 0.3275911 + 1\right)\right)\right)} + \left(0.254829592 + \frac{-0.284496736}{\left|x\right| \cdot 0.3275911 + 1}\right)}{e^{\left|x\right| \cdot \left|x\right|}}\]

Error

Bits error versus x

Derivation

  1. Initial program 13.9

    \[1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|}\]
  2. Using strategy rm
  3. Applied add-sqr-sqrt13.9

    \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{1}{\color{blue}{\sqrt{1 + 0.3275911 \cdot \left|x\right|} \cdot \sqrt{1 + 0.3275911 \cdot \left|x\right|}}} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|}\]
  4. Applied associate-/r*13.9

    \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \color{blue}{\frac{\frac{1}{\sqrt{1 + 0.3275911 \cdot \left|x\right|}}}{\sqrt{1 + 0.3275911 \cdot \left|x\right|}}} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|}\]
  5. Taylor expanded around 0 13.9

    \[\leadsto 1 - \left(\frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(0.254829592 + \color{blue}{\frac{1}{0.3275911 \cdot \left|x\right| + 1}} \cdot \left(-0.284496736 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(1.421413741 + \frac{1}{1 + 0.3275911 \cdot \left|x\right|} \cdot \left(-1.453152027 + \frac{\frac{1}{\sqrt{1 + 0.3275911 \cdot \left|x\right|}}}{\sqrt{1 + 0.3275911 \cdot \left|x\right|}} \cdot 1.061405429\right)\right)\right)\right)\right) \cdot e^{-\left|x\right| \cdot \left|x\right|}\]
  6. Applied simplify13.9

    \[\leadsto \color{blue}{1 - \frac{1}{\left|x\right| \cdot 0.3275911 + 1} \cdot \frac{\frac{\left(1.421413741 + \frac{-1.453152027}{\left|x\right| \cdot 0.3275911 + 1}\right) + \frac{\frac{1.061405429}{\left|x\right| \cdot 0.3275911 + 1}}{\left|x\right| \cdot 0.3275911 + 1}}{\frac{\left|x\right| \cdot 0.3275911 + 1}{\frac{1}{\left|x\right| \cdot 0.3275911 + 1}}} + \left(0.254829592 + \frac{-0.284496736}{\left|x\right| \cdot 0.3275911 + 1}\right)}{e^{\left|x\right| \cdot \left|x\right|}}}\]
  7. Using strategy rm
  8. Applied add-exp-log13.9

    \[\leadsto 1 - \frac{1}{\left|x\right| \cdot 0.3275911 + 1} \cdot \frac{\frac{\left(1.421413741 + \frac{-1.453152027}{\left|x\right| \cdot 0.3275911 + 1}\right) + \frac{\frac{1.061405429}{\left|x\right| \cdot 0.3275911 + 1}}{\left|x\right| \cdot 0.3275911 + 1}}{\frac{\left|x\right| \cdot 0.3275911 + 1}{\frac{1}{\color{blue}{e^{\log \left(\left|x\right| \cdot 0.3275911 + 1\right)}}}}} + \left(0.254829592 + \frac{-0.284496736}{\left|x\right| \cdot 0.3275911 + 1}\right)}{e^{\left|x\right| \cdot \left|x\right|}}\]
  9. Applied rec-exp13.9

    \[\leadsto 1 - \frac{1}{\left|x\right| \cdot 0.3275911 + 1} \cdot \frac{\frac{\left(1.421413741 + \frac{-1.453152027}{\left|x\right| \cdot 0.3275911 + 1}\right) + \frac{\frac{1.061405429}{\left|x\right| \cdot 0.3275911 + 1}}{\left|x\right| \cdot 0.3275911 + 1}}{\frac{\left|x\right| \cdot 0.3275911 + 1}{\color{blue}{e^{-\log \left(\left|x\right| \cdot 0.3275911 + 1\right)}}}} + \left(0.254829592 + \frac{-0.284496736}{\left|x\right| \cdot 0.3275911 + 1}\right)}{e^{\left|x\right| \cdot \left|x\right|}}\]
  10. Applied add-exp-log13.9

    \[\leadsto 1 - \frac{1}{\left|x\right| \cdot 0.3275911 + 1} \cdot \frac{\frac{\left(1.421413741 + \frac{-1.453152027}{\left|x\right| \cdot 0.3275911 + 1}\right) + \frac{\frac{1.061405429}{\left|x\right| \cdot 0.3275911 + 1}}{\left|x\right| \cdot 0.3275911 + 1}}{\frac{\color{blue}{e^{\log \left(\left|x\right| \cdot 0.3275911 + 1\right)}}}{e^{-\log \left(\left|x\right| \cdot 0.3275911 + 1\right)}}} + \left(0.254829592 + \frac{-0.284496736}{\left|x\right| \cdot 0.3275911 + 1}\right)}{e^{\left|x\right| \cdot \left|x\right|}}\]
  11. Applied div-exp13.9

    \[\leadsto 1 - \frac{1}{\left|x\right| \cdot 0.3275911 + 1} \cdot \frac{\frac{\left(1.421413741 + \frac{-1.453152027}{\left|x\right| \cdot 0.3275911 + 1}\right) + \frac{\frac{1.061405429}{\left|x\right| \cdot 0.3275911 + 1}}{\left|x\right| \cdot 0.3275911 + 1}}{\color{blue}{e^{\log \left(\left|x\right| \cdot 0.3275911 + 1\right) - \left(-\log \left(\left|x\right| \cdot 0.3275911 + 1\right)\right)}}} + \left(0.254829592 + \frac{-0.284496736}{\left|x\right| \cdot 0.3275911 + 1}\right)}{e^{\left|x\right| \cdot \left|x\right|}}\]
  12. Applied add-exp-log13.9

    \[\leadsto 1 - \frac{1}{\left|x\right| \cdot 0.3275911 + 1} \cdot \frac{\frac{\color{blue}{e^{\log \left(\left(1.421413741 + \frac{-1.453152027}{\left|x\right| \cdot 0.3275911 + 1}\right) + \frac{\frac{1.061405429}{\left|x\right| \cdot 0.3275911 + 1}}{\left|x\right| \cdot 0.3275911 + 1}\right)}}}{e^{\log \left(\left|x\right| \cdot 0.3275911 + 1\right) - \left(-\log \left(\left|x\right| \cdot 0.3275911 + 1\right)\right)}} + \left(0.254829592 + \frac{-0.284496736}{\left|x\right| \cdot 0.3275911 + 1}\right)}{e^{\left|x\right| \cdot \left|x\right|}}\]
  13. Applied div-exp13.9

    \[\leadsto 1 - \frac{1}{\left|x\right| \cdot 0.3275911 + 1} \cdot \frac{\color{blue}{e^{\log \left(\left(1.421413741 + \frac{-1.453152027}{\left|x\right| \cdot 0.3275911 + 1}\right) + \frac{\frac{1.061405429}{\left|x\right| \cdot 0.3275911 + 1}}{\left|x\right| \cdot 0.3275911 + 1}\right) - \left(\log \left(\left|x\right| \cdot 0.3275911 + 1\right) - \left(-\log \left(\left|x\right| \cdot 0.3275911 + 1\right)\right)\right)}} + \left(0.254829592 + \frac{-0.284496736}{\left|x\right| \cdot 0.3275911 + 1}\right)}{e^{\left|x\right| \cdot \left|x\right|}}\]

Runtime

Time bar (total: 1.3m)Debug logProfile

herbie shell --seed '#(1064300848 3212030778 2049303162 3567222883 2277747821 1384278011)' 
(FPCore (x)
  :name "Jmat.Real.erf"
  (- 1 (* (* (/ 1 (+ 1 (* 0.3275911 (fabs x)))) (+ 0.254829592 (* (/ 1 (+ 1 (* 0.3275911 (fabs x)))) (+ -0.284496736 (* (/ 1 (+ 1 (* 0.3275911 (fabs x)))) (+ 1.421413741 (* (/ 1 (+ 1 (* 0.3275911 (fabs x)))) (+ -1.453152027 (* (/ 1 (+ 1 (* 0.3275911 (fabs x)))) 1.061405429))))))))) (exp (- (* (fabs x) (fabs x)))))))