\[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}\]
Test:
NMSE problem 3.4.6
Bits:
128 bits
Bits error versus x
Bits error versus n
Time: 25.9 s
Input Error: 52.5
Output Error: 23.7
Log:
Profile: 🕒
\(\frac{\left(\frac{\frac{2}{x}}{n} - \frac{4}{x} \cdot \frac{\log x}{n \cdot n}\right) - \frac{\frac{1}{n}}{x \cdot x}}{{x}^{\left(\frac{1}{n}\right)} + {\left(1 + x\right)}^{\left(\frac{1}{n}\right)}}\)
  1. Started with
    \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}\]
    52.5
  2. Using strategy rm
    52.5
  3. Applied add-log-exp to get
    \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - \color{red}{{x}^{\left(\frac{1}{n}\right)}} \leadsto {\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - \color{blue}{\log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right)}\]
    52.6
  4. Applied add-log-exp to get
    \[\color{red}{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}} - \log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right) \leadsto \color{blue}{\log \left(e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}\right)} - \log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right)\]
    52.6
  5. Applied diff-log to get
    \[\color{red}{\log \left(e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}\right) - \log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right)} \leadsto \color{blue}{\log \left(\frac{e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}}{e^{{x}^{\left(\frac{1}{n}\right)}}}\right)}\]
    52.6
  6. Applied simplify to get
    \[\log \color{red}{\left(\frac{e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}}{e^{{x}^{\left(\frac{1}{n}\right)}}}\right)} \leadsto \log \color{blue}{\left(e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}}\right)}\]
    52.5
  7. Using strategy rm
    52.5
  8. Applied flip-- to get
    \[\log \left(e^{\color{red}{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}}}\right) \leadsto \log \left(e^{\color{blue}{\frac{{\left({\left(x + 1\right)}^{\left(\frac{1}{n}\right)}\right)}^2 - {\left({x}^{\left(\frac{1}{n}\right)}\right)}^2}{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} + {x}^{\left(\frac{1}{n}\right)}}}}\right)\]
    52.6
  9. Applied taylor to get
    \[\log \left(e^{\frac{{\left({\left(x + 1\right)}^{\left(\frac{1}{n}\right)}\right)}^2 - {\left({x}^{\left(\frac{1}{n}\right)}\right)}^2}{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} + {x}^{\left(\frac{1}{n}\right)}}}\right) \leadsto \log \left(e^{\frac{2 \cdot \frac{1}{n \cdot x} - \left(4 \cdot \frac{\log x}{{n}^2 \cdot x} + \frac{1}{n \cdot {x}^2}\right)}{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} + {x}^{\left(\frac{1}{n}\right)}}}\right)\]
    44.1
  10. Taylor expanded around inf to get
    \[\log \left(e^{\frac{\color{red}{2 \cdot \frac{1}{n \cdot x} - \left(4 \cdot \frac{\log x}{{n}^2 \cdot x} + \frac{1}{n \cdot {x}^2}\right)}}{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} + {x}^{\left(\frac{1}{n}\right)}}}\right) \leadsto \log \left(e^{\frac{\color{blue}{2 \cdot \frac{1}{n \cdot x} - \left(4 \cdot \frac{\log x}{{n}^2 \cdot x} + \frac{1}{n \cdot {x}^2}\right)}}{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} + {x}^{\left(\frac{1}{n}\right)}}}\right)\]
    44.1
  11. Applied simplify to get
    \[\log \left(e^{\frac{2 \cdot \frac{1}{n \cdot x} - \left(4 \cdot \frac{\log x}{{n}^2 \cdot x} + \frac{1}{n \cdot {x}^2}\right)}{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} + {x}^{\left(\frac{1}{n}\right)}}}\right) \leadsto \frac{\left(\frac{\frac{2}{x}}{n} - \frac{4}{x} \cdot \frac{\log x}{n \cdot n}\right) - \frac{\frac{1}{n}}{x \cdot x}}{{x}^{\left(\frac{1}{n}\right)} + {\left(1 + x\right)}^{\left(\frac{1}{n}\right)}}\]
    23.7

  12. Applied final simplification

Original test:


(lambda ((x default) (n default))
  #:name "NMSE problem 3.4.6"
  (- (pow (+ x 1) (/ 1 n)) (pow x (/ 1 n))))