Average Error: 32.8 → 17.7
Time: 1.4m
Precision: 64
Internal Precision: 1408
\[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}\]
\[\begin{array}{l} \mathbf{if}\;x \le 1.5640286848259907 \cdot 10^{-237}:\\ \;\;\;\;\left(-\frac{\log x}{n}\right) - \left(\frac{\log x}{\frac{n}{\frac{1}{2}}} \cdot \frac{\log x}{n} - \left({\left(1 + x\right)}^{\left(\frac{1}{n}\right)} - 1\right)\right)\\ \mathbf{if}\;x \le 7.696574555670648 \cdot 10^{-204}:\\ \;\;\;\;\log \left(e^{{\left(1 + x\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}}\right)\\ \mathbf{if}\;x \le 0.7612041009958095:\\ \;\;\;\;\left(-\frac{\log x}{n}\right) - \left(\frac{\log x}{\frac{n}{\frac{1}{2}}} \cdot \frac{\log x}{n} - \left({\left(1 + x\right)}^{\left(\frac{1}{n}\right)} - 1\right)\right)\\ \mathbf{if}\;x \le 7.962327402555374 \cdot 10^{+221}:\\ \;\;\;\;\left(\log 1 + \frac{\frac{\log x}{n \cdot n}}{x}\right) + \left(\frac{1}{n} \cdot \frac{1}{x} - \frac{\frac{\frac{1}{2}}{n}}{x \cdot x}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(e^{{\left(1 + x\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}}\right)\\ \end{array}\]

Error

Bits error versus x

Bits error versus n

Derivation

  1. Split input into 4 regimes
  2. if x < 1.5640286848259907e-237 or 7.696574555670648e-204 < x < 0.7612041009958095

    1. Initial program 47.5

      \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}\]
    2. Taylor expanded around inf 60.0

      \[\leadsto {\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - \color{blue}{\left(\left(\frac{1}{2} \cdot \frac{{\left(\log \left(\frac{1}{x}\right)\right)}^{2}}{{n}^{2}} + 1\right) - \frac{\log \left(\frac{1}{x}\right)}{n}\right)}\]
    3. Applied simplify14.3

      \[\leadsto \color{blue}{\left(-\frac{\log x}{n}\right) - \left(\frac{\log x}{\frac{n}{\frac{1}{2}}} \cdot \frac{\log x}{n} - \left({\left(1 + x\right)}^{\left(\frac{1}{n}\right)} - 1\right)\right)}\]

    if 1.5640286848259907e-237 < x < 7.696574555670648e-204

    1. Initial program 42.6

      \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}\]
    2. Using strategy rm
    3. Applied add-log-exp42.6

      \[\leadsto {\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - \color{blue}{\log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right)}\]
    4. Applied add-log-exp42.6

      \[\leadsto \color{blue}{\log \left(e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}\right)} - \log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right)\]
    5. Applied diff-log42.6

      \[\leadsto \color{blue}{\log \left(\frac{e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}}{e^{{x}^{\left(\frac{1}{n}\right)}}}\right)}\]
    6. Applied simplify42.6

      \[\leadsto \log \color{blue}{\left(e^{{\left(1 + x\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}}\right)}\]

    if 0.7612041009958095 < x < 7.962327402555374e+221

    1. Initial program 26.2

      \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}\]
    2. Using strategy rm
    3. Applied add-log-exp26.2

      \[\leadsto {\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - \color{blue}{\log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right)}\]
    4. Applied add-log-exp26.2

      \[\leadsto \color{blue}{\log \left(e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}\right)} - \log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right)\]
    5. Applied diff-log26.2

      \[\leadsto \color{blue}{\log \left(\frac{e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}}{e^{{x}^{\left(\frac{1}{n}\right)}}}\right)}\]
    6. Applied simplify26.2

      \[\leadsto \log \color{blue}{\left(e^{{\left(1 + x\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}}\right)}\]
    7. Taylor expanded around -inf 63.0

      \[\leadsto \log \left(e^{\color{blue}{\left(\frac{\log -1}{{n}^{2} \cdot x} + \frac{1}{n \cdot x}\right) - \left(\frac{\log \left(\frac{-1}{x}\right)}{{n}^{2} \cdot x} + \frac{1}{2} \cdot \frac{1}{n \cdot {x}^{2}}\right)}}\right)\]
    8. Applied simplify22.2

      \[\leadsto \color{blue}{\left(\log 1 + \frac{\frac{\log x}{n \cdot n}}{x}\right) + \left(\frac{\frac{1}{n}}{x} - \frac{\frac{\frac{1}{2}}{n}}{x \cdot x}\right)}\]
    9. Using strategy rm
    10. Applied div-inv22.2

      \[\leadsto \left(\log 1 + \frac{\frac{\log x}{n \cdot n}}{x}\right) + \left(\color{blue}{\frac{1}{n} \cdot \frac{1}{x}} - \frac{\frac{\frac{1}{2}}{n}}{x \cdot x}\right)\]

    if 7.962327402555374e+221 < x

    1. Initial program 7.0

      \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}\]
    2. Using strategy rm
    3. Applied add-log-exp7.2

      \[\leadsto {\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - \color{blue}{\log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right)}\]
    4. Applied add-log-exp7.0

      \[\leadsto \color{blue}{\log \left(e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}\right)} - \log \left(e^{{x}^{\left(\frac{1}{n}\right)}}\right)\]
    5. Applied diff-log7.0

      \[\leadsto \color{blue}{\log \left(\frac{e^{{\left(x + 1\right)}^{\left(\frac{1}{n}\right)}}}{e^{{x}^{\left(\frac{1}{n}\right)}}}\right)}\]
    6. Applied simplify7.0

      \[\leadsto \log \color{blue}{\left(e^{{\left(1 + x\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}}\right)}\]
  3. Recombined 4 regimes into one program.

Runtime

Time bar (total: 1.4m)Debug logProfile

herbie shell --seed '#(1064397287 3527694221 3797617954 1138343853 2854031332 1153838279)' 
(FPCore (x n)
  :name "2nthrt (problem 3.4.6)"
  (- (pow (+ x 1) (/ 1 n)) (pow x (/ 1 n))))