Average Error: 0.5 → 0.3
Time: 1.2m
Precision: 64
Internal Precision: 128
\[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}\]
\[\frac{\frac{\frac{\sqrt{1 - \left(v \cdot v\right) \cdot 5}}{\pi}}{\sqrt{2}} \cdot \frac{\frac{\sqrt{1 - \left(v \cdot v\right) \cdot 5}}{t}}{\sqrt{1 - 3 \cdot \left(v \cdot v\right)}}}{1 - v \cdot v}\]

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. Using strategy rm
  3. Applied associate-/r*0.5

    \[\leadsto \color{blue}{\frac{\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}}}{1 - v \cdot v}}\]
  4. Using strategy rm
  5. Applied associate-/r*0.5

    \[\leadsto \frac{\color{blue}{\frac{\frac{1 - 5 \cdot \left(v \cdot v\right)}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}}}}{1 - v \cdot v}\]
  6. Using strategy rm
  7. Applied sqrt-prod0.5

    \[\leadsto \frac{\frac{\frac{1 - 5 \cdot \left(v \cdot v\right)}{\pi \cdot t}}{\color{blue}{\sqrt{2} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}}}}{1 - v \cdot v}\]
  8. Applied add-sqr-sqrt0.5

    \[\leadsto \frac{\frac{\frac{\color{blue}{\sqrt{1 - 5 \cdot \left(v \cdot v\right)} \cdot \sqrt{1 - 5 \cdot \left(v \cdot v\right)}}}{\pi \cdot t}}{\sqrt{2} \cdot \sqrt{1 - 3 \cdot \left(v \cdot v\right)}}}{1 - v \cdot v}\]
  9. Applied times-frac0.4

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

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

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

Reproduce

herbie shell --seed 2019090 
(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)))))