Average Error: 0.4 → 0.5
Time: 1.1m
Precision: 64
Internal Precision: 128
\[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}\]
\[\frac{{2}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)} \cdot \left({n}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)} \cdot {\pi}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)}\right)}{\sqrt{k}}\]

Error

Bits error versus k

Bits error versus n

Derivation

  1. Initial program 0.4

    \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}\]
  2. Initial simplification0.4

    \[\leadsto \frac{{\left(\pi \cdot \left(n \cdot 2\right)\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}{\sqrt{k}}\]
  3. Taylor expanded around inf 17.7

    \[\leadsto \frac{\color{blue}{e^{\left(\frac{1}{2} - \frac{1}{2} \cdot k\right) \cdot \left(\log \left(2 \cdot \pi\right) - \log \left(\frac{1}{n}\right)\right)}}}{\sqrt{k}}\]
  4. Simplified0.6

    \[\leadsto \frac{\color{blue}{{\left(2 \cdot \pi\right)}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)} \cdot {n}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)}}}{\sqrt{k}}\]
  5. Using strategy rm
  6. Applied unpow-prod-down0.5

    \[\leadsto \frac{\color{blue}{\left({2}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)} \cdot {\pi}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)}\right)} \cdot {n}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)}}{\sqrt{k}}\]
  7. Applied associate-*l*0.5

    \[\leadsto \frac{\color{blue}{{2}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)} \cdot \left({\pi}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)} \cdot {n}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)}\right)}}{\sqrt{k}}\]
  8. Final simplification0.5

    \[\leadsto \frac{{2}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)} \cdot \left({n}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)} \cdot {\pi}^{\left((\frac{-1}{2} \cdot k + \frac{1}{2})_*\right)}\right)}{\sqrt{k}}\]

Runtime

Time bar (total: 1.1m)Debug logProfile

herbie shell --seed 2018349 +o rules:numerics
(FPCore (k n)
  :name "Migdal et al, Equation (51)"
  (* (/ 1 (sqrt k)) (pow (* (* 2 PI) n) (/ (- 1 k) 2))))