Average Error: 0.5 → 0.3
Time: 2.1m
Precision: 64
Internal Precision: 128
\[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}\]
\[\frac{\frac{\frac{1}{\pi}}{t}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}} \cdot \frac{\sqrt{1 - 5 \cdot \left(v \cdot v\right)}}{\frac{1 - v \cdot v}{\sqrt{1 - 5 \cdot \left(v \cdot v\right)}}}\]

Error

Bits error versus v

Bits error versus t

Derivation

  1. Initial program 0.5

    \[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}\]
  2. Taylor expanded around 0 0.5

    \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\color{blue}{\left(t \cdot \pi\right)} \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}\]
  3. Using strategy rm
  4. Applied *-un-lft-identity0.5

    \[\leadsto \frac{\color{blue}{1 \cdot \left(1 - 5 \cdot \left(v \cdot v\right)\right)}}{\left(\left(t \cdot \pi\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}\]
  5. Applied times-frac0.5

    \[\leadsto \color{blue}{\frac{1}{\left(t \cdot \pi\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}} \cdot \frac{1 - 5 \cdot \left(v \cdot v\right)}{1 - v \cdot v}}\]
  6. Simplified0.3

    \[\leadsto \color{blue}{\frac{\frac{\frac{1}{\pi}}{t}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}} \cdot \frac{1 - 5 \cdot \left(v \cdot v\right)}{1 - v \cdot v}\]
  7. Using strategy rm
  8. Applied add-sqr-sqrt0.3

    \[\leadsto \frac{\frac{\frac{1}{\pi}}{t}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}} \cdot \frac{\color{blue}{\sqrt{1 - 5 \cdot \left(v \cdot v\right)} \cdot \sqrt{1 - 5 \cdot \left(v \cdot v\right)}}}{1 - v \cdot v}\]
  9. Applied associate-/l*0.3

    \[\leadsto \frac{\frac{\frac{1}{\pi}}{t}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}} \cdot \color{blue}{\frac{\sqrt{1 - 5 \cdot \left(v \cdot v\right)}}{\frac{1 - v \cdot v}{\sqrt{1 - 5 \cdot \left(v \cdot v\right)}}}}\]
  10. Final simplification0.3

    \[\leadsto \frac{\frac{\frac{1}{\pi}}{t}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}} \cdot \frac{\sqrt{1 - 5 \cdot \left(v \cdot v\right)}}{\frac{1 - v \cdot v}{\sqrt{1 - 5 \cdot \left(v \cdot v\right)}}}\]

Reproduce

herbie shell --seed 2019089 +o rules:numerics
(FPCore (v t)
  :name "Falkner and Boettcher, Equation (20:1,3)"
  (/ (- 1 (* 5 (* v v))) (* (* (* PI t) (sqrt (* 2 (- 1 (* 3 (* v v)))))) (- 1 (* v v)))))