\[\frac{e^{x}}{e^{x} - 1}\]
Test:
NMSE section 3.11
Bits:
128 bits
Bits error versus x
Time: 5.1 s
Input Error: 18.3
Output Error: 0.6
Log:
Profile: 🕒
\({\left(\frac{\sqrt[3]{e^{x}}}{\sqrt[3]{{x}^2 \cdot \left(x \cdot \frac{1}{6} + \frac{1}{2}\right) + x}}\right)}^3\)
  1. Started with
    \[\frac{e^{x}}{e^{x} - 1}\]
    18.3
  2. Applied taylor to get
    \[\frac{e^{x}}{e^{x} - 1} \leadsto \frac{e^{x}}{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}\]
    5.2
  3. Taylor expanded around 0 to get
    \[\frac{e^{x}}{\color{red}{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}} \leadsto \frac{e^{x}}{\color{blue}{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}}\]
    5.2
  4. Using strategy rm
    5.2
  5. Applied add-cube-cbrt to get
    \[\frac{e^{x}}{\color{red}{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}} \leadsto \frac{e^{x}}{\color{blue}{{\left(\sqrt[3]{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}\right)}^3}}\]
    5.6
  6. Applied add-cube-cbrt to get
    \[\frac{\color{red}{e^{x}}}{{\left(\sqrt[3]{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}\right)}^3} \leadsto \frac{\color{blue}{{\left(\sqrt[3]{e^{x}}\right)}^3}}{{\left(\sqrt[3]{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}\right)}^3}\]
    5.7
  7. Applied cube-undiv to get
    \[\color{red}{\frac{{\left(\sqrt[3]{e^{x}}\right)}^3}{{\left(\sqrt[3]{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}\right)}^3}} \leadsto \color{blue}{{\left(\frac{\sqrt[3]{e^{x}}}{\sqrt[3]{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}}\right)}^3}\]
    5.7
  8. Applied simplify to get
    \[{\color{red}{\left(\frac{\sqrt[3]{e^{x}}}{\sqrt[3]{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}}\right)}}^3 \leadsto {\color{blue}{\left(\frac{\sqrt[3]{e^{x}}}{\sqrt[3]{{x}^2 \cdot \left(x \cdot \frac{1}{6} + \frac{1}{2}\right) + x}}\right)}}^3\]
    0.6

Original test:


(lambda ((x default))
  #:name "NMSE section 3.11"
  (/ (exp x) (- (exp x) 1))
  #:target
  (/ 1 (- 1 (exp (- x)))))