
(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:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(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}
(FPCore (v) :precision binary64 (/ 4.0 (* (PI) (* 3.0 (* (sqrt (fma -6.0 (* v v) 2.0)) (- 1.0 (* v v)))))))
\begin{array}{l}
\\
\frac{4}{\mathsf{PI}\left(\right) \cdot \left(3 \cdot \left(\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(1 - v \cdot v\right)\right)\right)}
\end{array}
Initial program 98.5%
lift-*.f64N/A
lift-*.f64N/A
associate-*l*N/A
lift-*.f64N/A
*-commutativeN/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
*-commutativeN/A
lower-*.f64100.0
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
lower-fma.f64N/A
metadata-eval100.0
Applied rewrites100.0%
(FPCore (v) :precision binary64 (/ 1.3333333333333333 (* (sqrt (fma -6.0 (* v v) 2.0)) (* (- 1.0 (* v v)) (PI)))))
\begin{array}{l}
\\
\frac{1.3333333333333333}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)} \cdot \left(\left(1 - v \cdot v\right) \cdot \mathsf{PI}\left(\right)\right)}
\end{array}
Initial program 98.5%
lift-*.f64N/A
lift-*.f64N/A
lift-*.f64N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
*-commutativeN/A
lower-*.f6498.5
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
lower-fma.f64N/A
metadata-eval98.5
Applied rewrites98.5%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f64100.0
lift-*.f64N/A
*-commutativeN/A
lower-*.f64100.0
Applied rewrites100.0%
(FPCore (v) :precision binary64 (/ (/ 4.0 (sqrt (fma -6.0 (* v v) 2.0))) (* (PI) 3.0)))
\begin{array}{l}
\\
\frac{\frac{4}{\sqrt{\mathsf{fma}\left(-6, v \cdot v, 2\right)}}}{\mathsf{PI}\left(\right) \cdot 3}
\end{array}
Initial program 98.5%
Taylor expanded in v around 0
Applied rewrites97.7%
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
metadata-evalN/A
+-commutativeN/A
lift-fma.f64N/A
associate-/r*N/A
lower-/.f64N/A
Applied rewrites99.2%
(FPCore (v) :precision binary64 (/ 1.3333333333333333 (* (- 1.0 (* v v)) (* (PI) (sqrt 2.0)))))
\begin{array}{l}
\\
\frac{1.3333333333333333}{\left(1 - v \cdot v\right) \cdot \left(\mathsf{PI}\left(\right) \cdot \sqrt{2}\right)}
\end{array}
Initial program 98.5%
lift-*.f64N/A
lift-*.f64N/A
lift-*.f64N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
*-commutativeN/A
lower-*.f6498.5
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
lower-fma.f64N/A
metadata-eval98.5
Applied rewrites98.5%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f64100.0
lift-*.f64N/A
*-commutativeN/A
lower-*.f64100.0
Applied rewrites100.0%
Taylor expanded in v around 0
Applied rewrites99.2%
lift-*.f64N/A
*-commutativeN/A
lift-*.f64N/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f6499.2
Applied rewrites99.2%
(FPCore (v) :precision binary64 (/ 1.3333333333333333 (* (sqrt 2.0) (* (- 1.0 (* v v)) (PI)))))
\begin{array}{l}
\\
\frac{1.3333333333333333}{\sqrt{2} \cdot \left(\left(1 - v \cdot v\right) \cdot \mathsf{PI}\left(\right)\right)}
\end{array}
Initial program 98.5%
lift-*.f64N/A
lift-*.f64N/A
lift-*.f64N/A
associate-*l*N/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
*-commutativeN/A
lower-*.f6498.5
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
lower-fma.f64N/A
metadata-eval98.5
Applied rewrites98.5%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f64100.0
lift-*.f64N/A
*-commutativeN/A
lower-*.f64100.0
Applied rewrites100.0%
Taylor expanded in v around 0
Applied rewrites99.2%
(FPCore (v) :precision binary64 (* (sqrt 0.5) (/ 1.3333333333333333 (PI))))
\begin{array}{l}
\\
\sqrt{0.5} \cdot \frac{1.3333333333333333}{\mathsf{PI}\left(\right)}
\end{array}
Initial program 98.5%
Taylor expanded in v around 0
Applied rewrites97.6%
Applied rewrites99.2%
herbie shell --seed 2025019
(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)))))))