
(FPCore (g h) :precision binary64 (* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))
\begin{array}{l}
\\
2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 5 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (g h) :precision binary64 (* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))
\begin{array}{l}
\\
2 \cdot \cos \left(\frac{2 \cdot \mathsf{PI}\left(\right)}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)
\end{array}
(FPCore (g h)
:precision binary64
(let* ((t_0 (acos (/ (- g) h))))
(fma
(* (sin (* t_0 0.3333333333333333)) (sin (* (PI) 0.6666666666666666)))
-2.0
(- (cos (* t_0 -0.3333333333333333))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \cos^{-1} \left(\frac{-g}{h}\right)\\
\mathsf{fma}\left(\sin \left(t\_0 \cdot 0.3333333333333333\right) \cdot \sin \left(\mathsf{PI}\left(\right) \cdot 0.6666666666666666\right), -2, -\cos \left(t\_0 \cdot -0.3333333333333333\right)\right)
\end{array}
\end{array}
Initial program 98.4%
Applied rewrites100.0%
Taylor expanded in g around 0
Applied rewrites98.5%
Applied rewrites100.0%
(FPCore (g h)
:precision binary64
(let* ((t_0 (acos (/ (- g) h))))
(fma
(* -2.0 (sin (* 0.6666666666666666 (PI))))
(sin (* t_0 0.3333333333333333))
(- (cos (* -0.3333333333333333 t_0))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \cos^{-1} \left(\frac{-g}{h}\right)\\
\mathsf{fma}\left(-2 \cdot \sin \left(0.6666666666666666 \cdot \mathsf{PI}\left(\right)\right), \sin \left(t\_0 \cdot 0.3333333333333333\right), -\cos \left(-0.3333333333333333 \cdot t\_0\right)\right)
\end{array}
\end{array}
Initial program 98.4%
Applied rewrites100.0%
Taylor expanded in g around 0
Applied rewrites98.5%
(FPCore (g h) :precision binary64 (* 2.0 (cos (/ (+ 3.0 (* (/ 1.5 (PI)) (acos (/ (- g) h)))) (/ 4.5 (PI))))))
\begin{array}{l}
\\
2 \cdot \cos \left(\frac{3 + \frac{1.5}{\mathsf{PI}\left(\right)} \cdot \cos^{-1} \left(\frac{-g}{h}\right)}{\frac{4.5}{\mathsf{PI}\left(\right)}}\right)
\end{array}
Initial program 98.4%
lift-+.f64N/A
lift-/.f64N/A
clear-numN/A
lift-/.f64N/A
frac-addN/A
lower-/.f64N/A
metadata-evalN/A
lower-+.f64N/A
lower-*.f64N/A
lift-*.f64N/A
associate-/r*N/A
lower-/.f64N/A
metadata-evalN/A
lower-*.f64N/A
Applied rewrites98.5%
lift-*.f64N/A
lift-/.f64N/A
associate-*l/N/A
lower-/.f64N/A
metadata-eval98.5
Applied rewrites98.5%
(FPCore (g h) :precision binary64 (* 2.0 (cos (fma (PI) 0.6666666666666666 (* 0.3333333333333333 (acos (/ (- g) h)))))))
\begin{array}{l}
\\
2 \cdot \cos \left(\mathsf{fma}\left(\mathsf{PI}\left(\right), 0.6666666666666666, 0.3333333333333333 \cdot \cos^{-1} \left(\frac{-g}{h}\right)\right)\right)
\end{array}
Initial program 98.4%
lift-+.f64N/A
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
*-commutativeN/A
associate-*l*N/A
lower-fma.f64N/A
metadata-evalN/A
metadata-eval98.5
lift-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
metadata-eval98.5
Applied rewrites98.5%
(FPCore (g h) :precision binary64 (* 2.0 (cos (* 0.3333333333333333 (fma (PI) 2.0 (acos (/ (- g) h)))))))
\begin{array}{l}
\\
2 \cdot \cos \left(0.3333333333333333 \cdot \mathsf{fma}\left(\mathsf{PI}\left(\right), 2, \cos^{-1} \left(\frac{-g}{h}\right)\right)\right)
\end{array}
Initial program 98.4%
lift-+.f64N/A
lift-/.f64N/A
div-invN/A
lift-/.f64N/A
div-invN/A
distribute-rgt-outN/A
lower-*.f64N/A
metadata-evalN/A
lift-*.f64N/A
*-commutativeN/A
lower-fma.f6498.4
Applied rewrites98.4%
herbie shell --seed 2024314
(FPCore (g h)
:name "2-ancestry mixing, negative discriminant"
:precision binary64
(* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))