Falkner and Boettcher, Equation (22+)

Percentage Accurate: 98.5% → 100.0%
Time: 6.3s
Alternatives: 5
Speedup: 2.1×

Specification

?
\[\begin{array}{l} \\ \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \end{array} \]
(FPCore (v)
 :precision binary64
 (/ 4.0 (* (* (* 3.0 (PI)) (- 1.0 (* v v))) (sqrt (- 2.0 (* 6.0 (* v v)))))))
\begin{array}{l}

\\
\frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 5 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 98.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \end{array} \]
(FPCore (v)
 :precision binary64
 (/ 4.0 (* (* (* 3.0 (PI)) (- 1.0 (* v v))) (sqrt (- 2.0 (* 6.0 (* v v)))))))
\begin{array}{l}

\\
\frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}
\end{array}

Alternative 1: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{4}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)\right)} \end{array} \]
(FPCore (v)
 :precision binary64
 (/ 4.0 (* (PI) (* 3.0 (* (- 1.0 (* v v)) (sqrt (fma (* v v) -6.0 2.0)))))))
\begin{array}{l}

\\
\frac{4}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)\right)}
\end{array}
Derivation
  1. Initial program 98.5%

    \[\frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. lift-*.f64N/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - \color{blue}{6 \cdot \left(v \cdot v\right)}}} \]
    3. fp-cancel-sub-sign-invN/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{2 + \left(\mathsf{neg}\left(6\right)\right) \cdot \left(v \cdot v\right)}}} \]
    4. +-commutativeN/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{\left(\mathsf{neg}\left(6\right)\right) \cdot \left(v \cdot v\right) + 2}}} \]
    5. *-commutativeN/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{\left(v \cdot v\right) \cdot \left(\mathsf{neg}\left(6\right)\right)} + 2}} \]
    6. lower-fma.f64N/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{\mathsf{fma}\left(v \cdot v, \mathsf{neg}\left(6\right), 2\right)}}} \]
    7. metadata-eval98.5

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, \color{blue}{-6}, 2\right)}} \]
  4. Applied rewrites98.5%

    \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}} \]
  5. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}} \]
    2. lift-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right)} \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}} \]
    3. associate-*l*N/A

      \[\leadsto \frac{4}{\color{blue}{\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)}} \]
    4. lift-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\left(3 \cdot \mathsf{PI}\left(\right)\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)} \]
    5. *-commutativeN/A

      \[\leadsto \frac{4}{\color{blue}{\left(\mathsf{PI}\left(\right) \cdot 3\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)} \]
    6. lift-fma.f64N/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\color{blue}{\left(v \cdot v\right) \cdot -6 + 2}}\right)} \]
    7. +-commutativeN/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\color{blue}{2 + \left(v \cdot v\right) \cdot -6}}\right)} \]
    8. *-commutativeN/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 + \color{blue}{-6 \cdot \left(v \cdot v\right)}}\right)} \]
    9. metadata-evalN/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 + \color{blue}{\left(\mathsf{neg}\left(6\right)\right)} \cdot \left(v \cdot v\right)}\right)} \]
    10. fp-cancel-sub-sign-invN/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\color{blue}{2 - 6 \cdot \left(v \cdot v\right)}}\right)} \]
    11. lift-*.f64N/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 - \color{blue}{6 \cdot \left(v \cdot v\right)}}\right)} \]
    12. lift--.f64N/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\color{blue}{2 - 6 \cdot \left(v \cdot v\right)}}\right)} \]
    13. associate-*l*N/A

      \[\leadsto \frac{4}{\color{blue}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}\right)\right)}} \]
    14. lower-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}\right)\right)}} \]
    15. lower-*.f64N/A

      \[\leadsto \frac{4}{\mathsf{PI}\left(\right) \cdot \color{blue}{\left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}\right)\right)}} \]
  6. Applied rewrites100.0%

    \[\leadsto \frac{4}{\color{blue}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)\right)}} \]
  7. Add Preprocessing

Alternative 2: 99.0% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \frac{4}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(1 \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)\right)} \end{array} \]
(FPCore (v)
 :precision binary64
 (/ 4.0 (* (PI) (* 3.0 (* 1.0 (sqrt (fma (* v v) -6.0 2.0)))))))
\begin{array}{l}

\\
\frac{4}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(1 \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)\right)}
\end{array}
Derivation
  1. Initial program 98.5%

    \[\frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{2 - 6 \cdot \left(v \cdot v\right)}}} \]
    2. lift-*.f64N/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - \color{blue}{6 \cdot \left(v \cdot v\right)}}} \]
    3. fp-cancel-sub-sign-invN/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{2 + \left(\mathsf{neg}\left(6\right)\right) \cdot \left(v \cdot v\right)}}} \]
    4. +-commutativeN/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{\left(\mathsf{neg}\left(6\right)\right) \cdot \left(v \cdot v\right) + 2}}} \]
    5. *-commutativeN/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{\left(v \cdot v\right) \cdot \left(\mathsf{neg}\left(6\right)\right)} + 2}} \]
    6. lower-fma.f64N/A

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{\mathsf{fma}\left(v \cdot v, \mathsf{neg}\left(6\right), 2\right)}}} \]
    7. metadata-eval98.5

      \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, \color{blue}{-6}, 2\right)}} \]
  4. Applied rewrites98.5%

    \[\leadsto \frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\color{blue}{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}} \]
  5. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}}} \]
    2. lift-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right)} \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}} \]
    3. associate-*l*N/A

      \[\leadsto \frac{4}{\color{blue}{\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)}} \]
    4. lift-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\left(3 \cdot \mathsf{PI}\left(\right)\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)} \]
    5. *-commutativeN/A

      \[\leadsto \frac{4}{\color{blue}{\left(\mathsf{PI}\left(\right) \cdot 3\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)} \]
    6. lift-fma.f64N/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\color{blue}{\left(v \cdot v\right) \cdot -6 + 2}}\right)} \]
    7. +-commutativeN/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\color{blue}{2 + \left(v \cdot v\right) \cdot -6}}\right)} \]
    8. *-commutativeN/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 + \color{blue}{-6 \cdot \left(v \cdot v\right)}}\right)} \]
    9. metadata-evalN/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 + \color{blue}{\left(\mathsf{neg}\left(6\right)\right)} \cdot \left(v \cdot v\right)}\right)} \]
    10. fp-cancel-sub-sign-invN/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\color{blue}{2 - 6 \cdot \left(v \cdot v\right)}}\right)} \]
    11. lift-*.f64N/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 - \color{blue}{6 \cdot \left(v \cdot v\right)}}\right)} \]
    12. lift--.f64N/A

      \[\leadsto \frac{4}{\left(\mathsf{PI}\left(\right) \cdot 3\right) \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\color{blue}{2 - 6 \cdot \left(v \cdot v\right)}}\right)} \]
    13. associate-*l*N/A

      \[\leadsto \frac{4}{\color{blue}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}\right)\right)}} \]
    14. lower-*.f64N/A

      \[\leadsto \frac{4}{\color{blue}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}\right)\right)}} \]
    15. lower-*.f64N/A

      \[\leadsto \frac{4}{\mathsf{PI}\left(\right) \cdot \color{blue}{\left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}\right)\right)}} \]
  6. Applied rewrites100.0%

    \[\leadsto \frac{4}{\color{blue}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)\right)}} \]
  7. Taylor expanded in v around 0

    \[\leadsto \frac{4}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\color{blue}{1} \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)\right)} \]
  8. Step-by-step derivation
    1. Applied rewrites99.0%

      \[\leadsto \frac{4}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\color{blue}{1} \cdot \sqrt{\mathsf{fma}\left(v \cdot v, -6, 2\right)}\right)\right)} \]
    2. Add Preprocessing

    Alternative 3: 99.0% accurate, 1.5× speedup?

    \[\begin{array}{l} \\ \frac{1.3333333333333333}{\mathsf{PI}\left(\right) \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \end{array} \]
    (FPCore (v)
     :precision binary64
     (/ 1.3333333333333333 (* (PI) (sqrt (fma -6.0 (* v v) 2.0)))))
    \begin{array}{l}
    
    \\
    \frac{1.3333333333333333}{\mathsf{PI}\left(\right) \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}
    \end{array}
    
    Derivation
    1. Initial program 98.5%

      \[\frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    2. Add Preprocessing
    3. Applied rewrites99.0%

      \[\leadsto \color{blue}{\frac{1.3333333333333333}{\left(\mathsf{fma}\left(v, v, 1\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}} \]
    4. Taylor expanded in v around 0

      \[\leadsto \frac{\frac{4}{3}}{\color{blue}{\mathsf{PI}\left(\right)} \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    5. Step-by-step derivation
      1. lower-PI.f6499.0

        \[\leadsto \frac{1.3333333333333333}{\color{blue}{\mathsf{PI}\left(\right)} \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    6. Applied rewrites99.0%

      \[\leadsto \frac{1.3333333333333333}{\color{blue}{\mathsf{PI}\left(\right)} \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}} \]
    7. Add Preprocessing

    Alternative 4: 98.9% accurate, 2.1× speedup?

    \[\begin{array}{l} \\ \frac{1.3333333333333333}{\sqrt{2} \cdot \mathsf{PI}\left(\right)} \end{array} \]
    (FPCore (v) :precision binary64 (/ 1.3333333333333333 (* (sqrt 2.0) (PI))))
    \begin{array}{l}
    
    \\
    \frac{1.3333333333333333}{\sqrt{2} \cdot \mathsf{PI}\left(\right)}
    \end{array}
    
    Derivation
    1. Initial program 98.5%

      \[\frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    2. Add Preprocessing
    3. Applied rewrites99.0%

      \[\leadsto \color{blue}{\frac{1.3333333333333333}{\left(\mathsf{fma}\left(v, v, 1\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}} \]
    4. Taylor expanded in v around 0

      \[\leadsto \frac{\frac{4}{3}}{\color{blue}{\mathsf{PI}\left(\right) \cdot \sqrt{2}}} \]
    5. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\frac{4}{3}}{\color{blue}{\sqrt{2} \cdot \mathsf{PI}\left(\right)}} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\frac{4}{3}}{\color{blue}{\sqrt{2} \cdot \mathsf{PI}\left(\right)}} \]
      3. lower-sqrt.f64N/A

        \[\leadsto \frac{\frac{4}{3}}{\color{blue}{\sqrt{2}} \cdot \mathsf{PI}\left(\right)} \]
      4. lower-PI.f6499.0

        \[\leadsto \frac{1.3333333333333333}{\sqrt{2} \cdot \color{blue}{\mathsf{PI}\left(\right)}} \]
    6. Applied rewrites99.0%

      \[\leadsto \frac{1.3333333333333333}{\color{blue}{\sqrt{2} \cdot \mathsf{PI}\left(\right)}} \]
    7. Add Preprocessing

    Alternative 5: 97.4% accurate, 2.1× speedup?

    \[\begin{array}{l} \\ \frac{\sqrt{0.5}}{\mathsf{PI}\left(\right)} \cdot 1.3333333333333333 \end{array} \]
    (FPCore (v) :precision binary64 (* (/ (sqrt 0.5) (PI)) 1.3333333333333333))
    \begin{array}{l}
    
    \\
    \frac{\sqrt{0.5}}{\mathsf{PI}\left(\right)} \cdot 1.3333333333333333
    \end{array}
    
    Derivation
    1. Initial program 98.5%

      \[\frac{4}{\left(\left(3 \cdot \mathsf{PI}\left(\right)\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}} \]
    2. Add Preprocessing
    3. Taylor expanded in v around 0

      \[\leadsto \color{blue}{\frac{4}{3} \cdot \frac{\sqrt{\frac{1}{2}}}{\mathsf{PI}\left(\right)}} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\frac{\sqrt{\frac{1}{2}}}{\mathsf{PI}\left(\right)} \cdot \frac{4}{3}} \]
      2. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{\sqrt{\frac{1}{2}}}{\mathsf{PI}\left(\right)} \cdot \frac{4}{3}} \]
      3. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{\sqrt{\frac{1}{2}}}{\mathsf{PI}\left(\right)}} \cdot \frac{4}{3} \]
      4. lower-sqrt.f64N/A

        \[\leadsto \frac{\color{blue}{\sqrt{\frac{1}{2}}}}{\mathsf{PI}\left(\right)} \cdot \frac{4}{3} \]
      5. lower-PI.f6497.5

        \[\leadsto \frac{\sqrt{0.5}}{\color{blue}{\mathsf{PI}\left(\right)}} \cdot 1.3333333333333333 \]
    5. Applied rewrites97.5%

      \[\leadsto \color{blue}{\frac{\sqrt{0.5}}{\mathsf{PI}\left(\right)} \cdot 1.3333333333333333} \]
    6. Add Preprocessing

    Reproduce

    ?
    herbie shell --seed 2024351 
    (FPCore (v)
      :name "Falkner and Boettcher, Equation (22+)"
      :precision binary64
      (/ 4.0 (* (* (* 3.0 (PI)) (- 1.0 (* v v))) (sqrt (- 2.0 (* 6.0 (* v v)))))))