
(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 3 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 98.5%
Applied rewrites100.0%
Taylor expanded in g around 0
distribute-lft-inN/A
*-commutativeN/A
associate-*l*N/A
associate-*r*N/A
metadata-evalN/A
distribute-lft-outN/A
mul-1-negN/A
lower-neg.f64N/A
Applied rewrites98.5%
Applied rewrites100.0%
(FPCore (g h) :precision binary64 (* 2.0 (cos (/ (fma (acos (/ (- g) h)) 3.0 (* 6.0 (PI))) 9.0))))
\begin{array}{l}
\\
2 \cdot \cos \left(\frac{\mathsf{fma}\left(\cos^{-1} \left(\frac{-g}{h}\right), 3, 6 \cdot \mathsf{PI}\left(\right)\right)}{9}\right)
\end{array}
Initial program 98.5%
lift-+.f64N/A
lift-/.f64N/A
lift-/.f64N/A
frac-addN/A
lower-/.f64N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
*-commutativeN/A
lift-*.f64N/A
associate-*r*N/A
metadata-evalN/A
metadata-evalN/A
lower-*.f64N/A
metadata-evalN/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 98.5%
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%
herbie shell --seed 2024322
(FPCore (g h)
:name "2-ancestry mixing, negative discriminant"
:precision binary64
(* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))