Average Error: 29.4 → 1.1
Time: 5.2m
Precision: 64
Internal Precision: 1344
\[\frac{\left(1 + \frac{1}{\varepsilon}\right) \cdot e^{-\left(1 - \varepsilon\right) \cdot x} - \left(\frac{1}{\varepsilon} - 1\right) \cdot e^{-\left(1 + \varepsilon\right) \cdot x}}{2}\]
\[\begin{array}{l} \mathbf{if}\;x \le 0.6224483931737788:\\ \;\;\;\;\frac{\frac{\left(4 + \left(\frac{1}{16} \cdot {x}^{12} + \left(\frac{1}{6} \cdot {x}^{11} + \frac{8}{3} \cdot {x}^{3}\right)\right)\right) - \left({x}^{4} + \frac{1}{4} \cdot {x}^{8}\right)}{\left(2 + \frac{2}{3} \cdot {x}^{3}\right) + {x}^{2}}}{2}\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(1 + \frac{1}{\varepsilon}\right) \cdot e^{-\left(1 - \varepsilon\right) \cdot x} - \left(\frac{1}{\varepsilon} - 1\right) \cdot e^{-\sqrt[3]{{\left(x \cdot \varepsilon + x\right)}^{3}}}}{2}\\ \end{array}\]

Error

Bits error versus x

Bits error versus eps

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Split input into 2 regimes
  2. if x < 0.6224483931737788

    1. Initial program 39.3

      \[\frac{\left(1 + \frac{1}{\varepsilon}\right) \cdot e^{-\left(1 - \varepsilon\right) \cdot x} - \left(\frac{1}{\varepsilon} - 1\right) \cdot e^{-\left(1 + \varepsilon\right) \cdot x}}{2}\]
    2. Taylor expanded around 0 1.2

      \[\leadsto \frac{\color{blue}{\left(2 + \frac{2}{3} \cdot {x}^{3}\right) - {x}^{2}}}{2}\]
    3. Using strategy rm
    4. Applied flip--1.2

      \[\leadsto \frac{\color{blue}{\frac{\left(2 + \frac{2}{3} \cdot {x}^{3}\right) \cdot \left(2 + \frac{2}{3} \cdot {x}^{3}\right) - {x}^{2} \cdot {x}^{2}}{\left(2 + \frac{2}{3} \cdot {x}^{3}\right) + {x}^{2}}}}{2}\]
    5. Using strategy rm
    6. Applied flip--1.2

      \[\leadsto \frac{\frac{\color{blue}{\frac{\left(\left(2 + \frac{2}{3} \cdot {x}^{3}\right) \cdot \left(2 + \frac{2}{3} \cdot {x}^{3}\right)\right) \cdot \left(\left(2 + \frac{2}{3} \cdot {x}^{3}\right) \cdot \left(2 + \frac{2}{3} \cdot {x}^{3}\right)\right) - \left({x}^{2} \cdot {x}^{2}\right) \cdot \left({x}^{2} \cdot {x}^{2}\right)}{\left(2 + \frac{2}{3} \cdot {x}^{3}\right) \cdot \left(2 + \frac{2}{3} \cdot {x}^{3}\right) + {x}^{2} \cdot {x}^{2}}}}{\left(2 + \frac{2}{3} \cdot {x}^{3}\right) + {x}^{2}}}{2}\]
    7. Applied simplify1.2

      \[\leadsto \frac{\frac{\frac{\color{blue}{{\left(2 + \left(x \cdot x\right) \cdot \left(x \cdot \frac{2}{3}\right)\right)}^{\left(3 + 1\right)} - {\left(x \cdot x\right)}^{\left(3 + 1\right)}}}{\left(2 + \frac{2}{3} \cdot {x}^{3}\right) \cdot \left(2 + \frac{2}{3} \cdot {x}^{3}\right) + {x}^{2} \cdot {x}^{2}}}{\left(2 + \frac{2}{3} \cdot {x}^{3}\right) + {x}^{2}}}{2}\]
    8. Taylor expanded around 0 1.2

      \[\leadsto \frac{\frac{\color{blue}{\left(4 + \left(\frac{1}{16} \cdot {x}^{12} + \left(\frac{1}{6} \cdot {x}^{11} + \frac{8}{3} \cdot {x}^{3}\right)\right)\right) - \left({x}^{4} + \frac{1}{4} \cdot {x}^{8}\right)}}{\left(2 + \frac{2}{3} \cdot {x}^{3}\right) + {x}^{2}}}{2}\]

    if 0.6224483931737788 < x

    1. Initial program 0.7

      \[\frac{\left(1 + \frac{1}{\varepsilon}\right) \cdot e^{-\left(1 - \varepsilon\right) \cdot x} - \left(\frac{1}{\varepsilon} - 1\right) \cdot e^{-\left(1 + \varepsilon\right) \cdot x}}{2}\]
    2. Using strategy rm
    3. Applied add-cbrt-cube0.7

      \[\leadsto \frac{\left(1 + \frac{1}{\varepsilon}\right) \cdot e^{-\left(1 - \varepsilon\right) \cdot x} - \left(\frac{1}{\varepsilon} - 1\right) \cdot e^{-\color{blue}{\sqrt[3]{\left(\left(\left(1 + \varepsilon\right) \cdot x\right) \cdot \left(\left(1 + \varepsilon\right) \cdot x\right)\right) \cdot \left(\left(1 + \varepsilon\right) \cdot x\right)}}}}{2}\]
    4. Applied simplify0.7

      \[\leadsto \frac{\left(1 + \frac{1}{\varepsilon}\right) \cdot e^{-\left(1 - \varepsilon\right) \cdot x} - \left(\frac{1}{\varepsilon} - 1\right) \cdot e^{-\sqrt[3]{\color{blue}{{\left(x \cdot \varepsilon + x\right)}^{3}}}}}{2}\]
  3. Recombined 2 regimes into one program.

Runtime

Time bar (total: 5.2m)Debug logProfile

herbie shell --seed 2018201 
(FPCore (x eps)
  :name "NMSE Section 6.1 mentioned, A"
  (/ (- (* (+ 1 (/ 1 eps)) (exp (- (* (- 1 eps) x)))) (* (- (/ 1 eps) 1) (exp (- (* (+ 1 eps) x))))) 2))