Average Error: 0.4 → 0.3
Time: 1.2m
Precision: 64
Internal Precision: 128
\[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}\]
\[\frac{\sqrt{1 - \left(v \cdot v\right) \cdot 5}}{1 - v \cdot v} \cdot \left(\left(\frac{\frac{\frac{1}{\pi}}{\sqrt{2}}}{t} - \frac{\frac{v}{t} \cdot v}{\pi \cdot \sqrt{2}}\right) - \frac{\left(v \cdot v\right) \cdot \left(\frac{7}{2} \cdot \left(v \cdot v\right)\right)}{\left(\pi \cdot \sqrt{2}\right) \cdot t}\right)\]

Error

Bits error versus v

Bits error versus t

Derivation

  1. Initial program 0.4

    \[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}\]
  2. Using strategy rm
  3. Applied add-sqr-sqrt0.4

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

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

    \[\leadsto \color{blue}{\left(\frac{1}{t \cdot \left(\sqrt{2} \cdot \pi\right)} - \left(\frac{7}{2} \cdot \frac{{v}^{4}}{t \cdot \left(\sqrt{2} \cdot \pi\right)} + \frac{{v}^{2}}{t \cdot \left(\sqrt{2} \cdot \pi\right)}\right)\right)} \cdot \frac{\sqrt{1 - 5 \cdot \left(v \cdot v\right)}}{1 - v \cdot v}\]
  6. Simplified0.3

    \[\leadsto \color{blue}{\left(\left(\frac{\frac{\frac{1}{\pi}}{\sqrt{2}}}{t} - \frac{v \cdot \frac{v}{t}}{\sqrt{2} \cdot \pi}\right) - \frac{\left(v \cdot v\right) \cdot \left(\left(v \cdot v\right) \cdot \frac{7}{2}\right)}{\left(\sqrt{2} \cdot \pi\right) \cdot t}\right)} \cdot \frac{\sqrt{1 - 5 \cdot \left(v \cdot v\right)}}{1 - v \cdot v}\]
  7. Final simplification0.3

    \[\leadsto \frac{\sqrt{1 - \left(v \cdot v\right) \cdot 5}}{1 - v \cdot v} \cdot \left(\left(\frac{\frac{\frac{1}{\pi}}{\sqrt{2}}}{t} - \frac{\frac{v}{t} \cdot v}{\pi \cdot \sqrt{2}}\right) - \frac{\left(v \cdot v\right) \cdot \left(\frac{7}{2} \cdot \left(v \cdot v\right)\right)}{\left(\pi \cdot \sqrt{2}\right) \cdot t}\right)\]

Reproduce

herbie shell --seed 2019094 
(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)))))