Average Error: 40.4 → 19.5
Time: 15.1s
Precision: 64
Internal precision: 128
\[\log \left(N + 1\right) - \log N\]
⬇
\[\begin{array}{l}
\mathbf{if}\;N \le 37798.39342058285:\\
\;\;\;\;\log \left(\frac{N + 1}{N}\right)\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{N} + \frac{\frac{\frac{1}{3}}{N} - \frac{1}{2}}{{N}^2}\\
\end{array}\]
Derivation
- Split input into 2 regimes.
-
if N < 37798.39342058285
Initial program 31.2
\[\log \left(N + 1\right) - \log N\]
- Using strategy
rm
Applied diff-log 28.9
\[\leadsto \color{blue}{\log \left(\frac{N + 1}{N}\right)}\]
if 37798.39342058285 < N
Initial program 59.5
\[\log \left(N + 1\right) - \log N\]
Applied taylor 0.0
\[\leadsto \left(\frac{1}{N} + \frac{1}{3} \cdot \frac{1}{{N}^{3}}\right) - \frac{1}{2} \cdot \frac{1}{{N}^2}\]
Taylor expanded around inf 0.0
\[\leadsto \color{blue}{\left(\frac{1}{N} + \frac{1}{3} \cdot \frac{1}{{N}^{3}}\right) - \frac{1}{2} \cdot \frac{1}{{N}^2}}\]
Applied simplify 0.0
\[\leadsto \color{blue}{\frac{1}{N} + \frac{\frac{1}{N}}{N} \cdot \left(\frac{\frac{1}{3}}{N} - \frac{1}{2}\right)}\]
Applied simplify 0.0
\[\leadsto \frac{1}{N} + \color{blue}{\frac{\frac{\frac{1}{3}}{N} - \frac{1}{2}}{{N}^2}}\]
- Recombined 2 regimes into one program.
- Removed slow pow expressions
Runtime
Please include this information when filing a bug report:
herbie --seed '#(3042209127 2022729764 3313166321 4075783413 705100875 65069737)'
(FPCore (N)
:name "2log (problem 3.3.6)"
(- (log (+ N 1)) (log N)))