
(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 7 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 (sqrt (PI)))
(t_1 (* -0.1111111111111111 (* (acos (/ (- g) h)) -3.0))))
(*
(-
(* (cos (* 0.6666666666666666 (PI))) (cos t_1))
(* (sin (* (* t_0 0.6666666666666666) t_0)) (sin t_1)))
2.0)))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\mathsf{PI}\left(\right)}\\
t_1 := -0.1111111111111111 \cdot \left(\cos^{-1} \left(\frac{-g}{h}\right) \cdot -3\right)\\
\left(\cos \left(0.6666666666666666 \cdot \mathsf{PI}\left(\right)\right) \cdot \cos t\_1 - \sin \left(\left(t\_0 \cdot 0.6666666666666666\right) \cdot t\_0\right) \cdot \sin t\_1\right) \cdot 2
\end{array}
\end{array}
Initial program 98.4%
lift-+.f64N/A
+-commutativeN/A
lift-/.f64N/A
lift-/.f64N/A
frac-2negN/A
frac-addN/A
clear-numN/A
lower-/.f64N/A
lower-/.f64N/A
metadata-evalN/A
metadata-evalN/A
distribute-rgt-neg-outN/A
*-commutativeN/A
distribute-lft-neg-outN/A
lower-fma.f64N/A
Applied rewrites98.5%
lift-cos.f64N/A
lift-/.f64N/A
lift-/.f64N/A
associate-/r/N/A
lift-fma.f64N/A
distribute-rgt-inN/A
cos-sumN/A
lower--.f64N/A
Applied rewrites98.4%
lift-*.f64N/A
*-commutativeN/A
lift-*.f64N/A
associate-*r*N/A
metadata-evalN/A
lift-PI.f64N/A
add-sqr-sqrtN/A
associate-*r*N/A
lower-*.f64N/A
lower-*.f64N/A
lift-PI.f64N/A
lower-sqrt.f64N/A
lift-PI.f64N/A
lower-sqrt.f64100.0
Applied rewrites100.0%
lift-*.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-*l*N/A
metadata-evalN/A
lift-*.f64100.0
Applied rewrites100.0%
Final simplification100.0%
(FPCore (g h)
:precision binary64
(let* ((t_0 (acos (/ (- g) h)))
(t_1 (cos (fma 0.3333333333333333 t_0 (* -0.6666666666666666 (PI))))))
(*
(/
(* (cos (fma 0.3333333333333333 t_0 (* 0.6666666666666666 (PI)))) 2.0)
t_1)
t_1)))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \cos^{-1} \left(\frac{-g}{h}\right)\\
t_1 := \cos \left(\mathsf{fma}\left(0.3333333333333333, t\_0, -0.6666666666666666 \cdot \mathsf{PI}\left(\right)\right)\right)\\
\frac{\cos \left(\mathsf{fma}\left(0.3333333333333333, t\_0, 0.6666666666666666 \cdot \mathsf{PI}\left(\right)\right)\right) \cdot 2}{t\_1} \cdot t\_1
\end{array}
\end{array}
Initial program 98.4%
Applied rewrites98.4%
Applied rewrites99.9%
(FPCore (g h)
:precision binary64
(let* ((t_0 (* -0.6666666666666666 (PI))) (t_1 (acos (/ (- g) h))))
(*
(*
(cos (fma t_1 0.3333333333333333 (* 0.6666666666666666 (PI))))
(/ 2.0 (cos (fma t_1 0.3333333333333333 t_0))))
(cos (fma 0.3333333333333333 t_1 t_0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := -0.6666666666666666 \cdot \mathsf{PI}\left(\right)\\
t_1 := \cos^{-1} \left(\frac{-g}{h}\right)\\
\left(\cos \left(\mathsf{fma}\left(t\_1, 0.3333333333333333, 0.6666666666666666 \cdot \mathsf{PI}\left(\right)\right)\right) \cdot \frac{2}{\cos \left(\mathsf{fma}\left(t\_1, 0.3333333333333333, t\_0\right)\right)}\right) \cdot \cos \left(\mathsf{fma}\left(0.3333333333333333, t\_1, t\_0\right)\right)
\end{array}
\end{array}
Initial program 98.4%
Applied rewrites98.4%
Applied rewrites99.9%
lift-/.f64N/A
lift-*.f64N/A
associate-/l*N/A
*-commutativeN/A
lower-*.f64N/A
lower-/.f6499.9
lift-fma.f64N/A
*-commutativeN/A
lower-fma.f6499.9
Applied rewrites99.9%
Final simplification99.9%
(FPCore (g h) :precision binary64 (* (cos (/ (fma (/ 1.5 (PI)) (acos (/ (- g) h)) 3.0) (/ -4.5 (PI)))) 2.0))
\begin{array}{l}
\\
\cos \left(\frac{\mathsf{fma}\left(\frac{1.5}{\mathsf{PI}\left(\right)}, \cos^{-1} \left(\frac{-g}{h}\right), 3\right)}{\frac{-4.5}{\mathsf{PI}\left(\right)}}\right) \cdot 2
\end{array}
Initial program 98.4%
lift-+.f64N/A
+-commutativeN/A
lift-/.f64N/A
lift-/.f64N/A
clear-numN/A
frac-addN/A
lower-/.f64N/A
metadata-evalN/A
lower-fma.f64N/A
lift-*.f64N/A
associate-/r*N/A
lower-/.f64N/A
metadata-evalN/A
lower-*.f64N/A
lift-*.f64N/A
associate-/r*N/A
lower-/.f64N/A
metadata-eval98.5
Applied rewrites98.5%
lift-*.f64N/A
*-commutativeN/A
lower-*.f6498.5
Applied rewrites98.5%
(FPCore (g h) :precision binary64 (* (cos (/ 1.0 (/ -9.0 (fma (acos (/ (- g) h)) -3.0 (* -6.0 (PI)))))) 2.0))
\begin{array}{l}
\\
\cos \left(\frac{1}{\frac{-9}{\mathsf{fma}\left(\cos^{-1} \left(\frac{-g}{h}\right), -3, -6 \cdot \mathsf{PI}\left(\right)\right)}}\right) \cdot 2
\end{array}
Initial program 98.4%
lift-+.f64N/A
+-commutativeN/A
lift-/.f64N/A
lift-/.f64N/A
frac-2negN/A
frac-addN/A
clear-numN/A
lower-/.f64N/A
lower-/.f64N/A
metadata-evalN/A
metadata-evalN/A
distribute-rgt-neg-outN/A
*-commutativeN/A
distribute-lft-neg-outN/A
lower-fma.f64N/A
Applied rewrites98.5%
Final simplification98.5%
(FPCore (g h) :precision binary64 (* (cos (/ (fma (acos (/ (- g) h)) 3.0 (* 6.0 (PI))) 9.0)) 2.0))
\begin{array}{l}
\\
\cos \left(\frac{\mathsf{fma}\left(\cos^{-1} \left(\frac{-g}{h}\right), 3, 6 \cdot \mathsf{PI}\left(\right)\right)}{9}\right) \cdot 2
\end{array}
Initial program 98.4%
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%
Final simplification98.5%
(FPCore (g h) :precision binary64 (* (cos (fma (PI) 0.6666666666666666 (* 0.3333333333333333 (acos (/ (- g) h))))) 2.0))
\begin{array}{l}
\\
\cos \left(\mathsf{fma}\left(\mathsf{PI}\left(\right), 0.6666666666666666, 0.3333333333333333 \cdot \cos^{-1} \left(\frac{-g}{h}\right)\right)\right) \cdot 2
\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%
Final simplification98.5%
herbie shell --seed 2024253
(FPCore (g h)
:name "2-ancestry mixing, negative discriminant"
:precision binary64
(* 2.0 (cos (+ (/ (* 2.0 (PI)) 3.0) (/ (acos (/ (- g) h)) 3.0)))))