Average Error: 29.0 → 0.2
Time: 41.9s
Precision: 64
Internal Precision: 1600
\[\log \left(N + 1\right) - \log N\]
\[\begin{array}{l} \mathbf{if}\;\log \left(N + 1\right) - \log N \le 3.158716666007422 \cdot 10^{-08}:\\ \;\;\;\;\frac{1}{N} + \frac{1}{N \cdot N} \cdot \left(\frac{\frac{1}{3}}{N} + \frac{-1}{2}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\sqrt[3]{N + 1} \cdot \sqrt[3]{N + 1}\right) + \left(\log \left(\sqrt[3]{N + 1}\right) - \log N\right)\\ \end{array}\]

Error

Bits error versus N

Derivation

  1. Split input into 2 regimes
  2. if (- (log (+ N 1)) (log N)) < 3.158716666007422e-08

    1. Initial program 60.0

      \[\log \left(N + 1\right) - \log N\]
    2. Taylor expanded around inf 0.0

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

      \[\leadsto \color{blue}{\frac{1}{N} + \frac{1}{N \cdot N} \cdot \left(\frac{\frac{1}{3}}{N} + \frac{-1}{2}\right)}\]

    if 3.158716666007422e-08 < (- (log (+ N 1)) (log N))

    1. Initial program 0.3

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

      \[\leadsto \log \color{blue}{\left(\left(\sqrt[3]{N + 1} \cdot \sqrt[3]{N + 1}\right) \cdot \sqrt[3]{N + 1}\right)} - \log N\]
    4. Applied log-prod0.3

      \[\leadsto \color{blue}{\left(\log \left(\sqrt[3]{N + 1} \cdot \sqrt[3]{N + 1}\right) + \log \left(\sqrt[3]{N + 1}\right)\right)} - \log N\]
    5. Applied associate--l+0.3

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

Runtime

Time bar (total: 41.9s)Debug logProfile

herbie shell --seed '#(1071373924 2949776965 1885069702 3247780810 90874544 2263903749)' 
(FPCore (N)
  :name "2log (problem 3.3.6)"
  (- (log (+ N 1)) (log N)))