Average Error: 30.0 → 0.3
Time: 40.9s
Precision: 64
Internal Precision: 1408
\[\log \left(N + 1\right) - \log N\]
\[\begin{array}{l} \mathbf{if}\;\log \left(N + 1\right) - \log N \le 3.887471677899157 \cdot 10^{-09}:\\ \;\;\;\;\frac{1}{N} - (\left(\frac{1}{N}\right) \cdot \left(\frac{\frac{1}{2}}{N}\right) + \left(\log 1\right))_*\\ \mathbf{else}:\\ \;\;\;\;(\left(\sqrt[3]{\log \left(N + 1\right)} \cdot \sqrt[3]{\log \left(N + 1\right)}\right) \cdot \left(\sqrt[3]{\log \left(N + 1\right)}\right) + \left(-\log N\right))_*\\ \end{array}\]

Error

Bits error versus N

Derivation

  1. Split input into 2 regimes
  2. if (- (log (+ N 1)) (log N)) < 3.887471677899157e-09

    1. Initial program 60.1

      \[\log \left(N + 1\right) - \log N\]
    2. Taylor expanded around inf 60.1

      \[\leadsto \color{blue}{\left(\frac{1}{N} - \left(\log \left(\frac{1}{N}\right) + \frac{1}{2} \cdot \frac{1}{{N}^{2}}\right)\right)} - \log N\]
    3. Applied simplify0.0

      \[\leadsto \color{blue}{\frac{1}{N} - (\left(\frac{1}{N}\right) \cdot \left(\frac{\frac{1}{2}}{N}\right) + \left(\log 1\right))_*}\]

    if 3.887471677899157e-09 < (- (log (+ N 1)) (log N))

    1. Initial program 0.4

      \[\log \left(N + 1\right) - \log N\]
    2. Using strategy rm
    3. Applied add-cube-cbrt0.5

      \[\leadsto \color{blue}{\left(\sqrt[3]{\log \left(N + 1\right)} \cdot \sqrt[3]{\log \left(N + 1\right)}\right) \cdot \sqrt[3]{\log \left(N + 1\right)}} - \log N\]
    4. Applied fma-neg0.5

      \[\leadsto \color{blue}{(\left(\sqrt[3]{\log \left(N + 1\right)} \cdot \sqrt[3]{\log \left(N + 1\right)}\right) \cdot \left(\sqrt[3]{\log \left(N + 1\right)}\right) + \left(-\log N\right))_*}\]
  3. Recombined 2 regimes into one program.

Runtime

Time bar (total: 40.9s)Debug logProfile

herbie shell --seed '#(1070100504 930361288 1279167582 284574201 1450237281 2578255382)' +o rules:numerics
(FPCore (N)
  :name "2log (problem 3.3.6)"
  (- (log (+ N 1)) (log N)))