
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (cbrt (PI))))
(*
(sqrt (+ (- (log1p (* (- u1) u1))) (log1p u1)))
(sin (fma (pow t_0 2.0) (* t_0 u2) (* u2 (PI)))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{\mathsf{PI}\left(\right)}\\
\sqrt{\left(-\mathsf{log1p}\left(\left(-u1\right) \cdot u1\right)\right) + \mathsf{log1p}\left(u1\right)} \cdot \sin \left(\mathsf{fma}\left({t\_0}^{2}, t\_0 \cdot u2, u2 \cdot \mathsf{PI}\left(\right)\right)\right)
\end{array}
\end{array}
Initial program 57.9%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lift--.f32N/A
flip--N/A
associate-/r/N/A
log-prodN/A
lower-+.f32N/A
log-recN/A
lower-neg.f32N/A
metadata-evalN/A
fp-cancel-sub-sign-invN/A
lower-log1p.f32N/A
lower-*.f32N/A
lower-neg.f32N/A
lower-log1p.f3298.4
Applied rewrites98.4%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
count-2-revN/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-*l*N/A
lower-fma.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
*-commutativeN/A
lower-*.f3298.5
Applied rewrites98.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (cbrt (PI))))
(*
(sqrt (- (log1p (- u1))))
(sin (fma (pow t_0 2.0) (* t_0 u2) (* u2 (PI)))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt[3]{\mathsf{PI}\left(\right)}\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(\mathsf{fma}\left({t\_0}^{2}, t\_0 \cdot u2, u2 \cdot \mathsf{PI}\left(\right)\right)\right)
\end{array}
\end{array}
Initial program 57.9%
lift-log.f32N/A
lift--.f32N/A
*-lft-identityN/A
fp-cancel-sub-sign-invN/A
distribute-lft-neg-inN/A
*-lft-identityN/A
lower-log1p.f32N/A
lower-neg.f3298.4
Applied rewrites98.4%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
count-2-revN/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-*l*N/A
lower-fma.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
*-commutativeN/A
lower-*.f3298.5
Applied rewrites98.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Initial program 57.9%
lift-log.f32N/A
lift--.f32N/A
*-lft-identityN/A
fp-cancel-sub-sign-invN/A
distribute-lft-neg-inN/A
*-lft-identityN/A
lower-log1p.f32N/A
lower-neg.f3298.4
Applied rewrites98.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (* (fma (fma (fma 0.25 u1 0.3333333333333333) u1 0.5) u1 1.0) u1)) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.25, u1, 0.3333333333333333\right), u1, 0.5\right), u1, 1\right) \cdot u1} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Initial program 57.9%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
lower-fma.f3293.8
Applied rewrites93.8%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (* (fma (fma 0.3333333333333333 u1 0.5) u1 1.0) u1)) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{\mathsf{fma}\left(\mathsf{fma}\left(0.3333333333333333, u1, 0.5\right), u1, 1\right) \cdot u1} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Initial program 57.9%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
lower-fma.f3291.7
Applied rewrites91.7%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (fma (* 0.5 u1) u1 u1)) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{\mathsf{fma}\left(0.5 \cdot u1, u1, u1\right)} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Initial program 57.9%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
lower-fma.f3287.5
Applied rewrites87.5%
Applied rewrites87.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (* (fma 0.5 u1 1.0) u1)) (sin (* (PI) (+ u2 u2)))))
\begin{array}{l}
\\
\sqrt{\mathsf{fma}\left(0.5, u1, 1\right) \cdot u1} \cdot \sin \left(\mathsf{PI}\left(\right) \cdot \left(u2 + u2\right)\right)
\end{array}
Initial program 57.9%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lift--.f32N/A
flip--N/A
associate-/r/N/A
log-prodN/A
lower-+.f32N/A
log-recN/A
lower-neg.f32N/A
metadata-evalN/A
fp-cancel-sub-sign-invN/A
lower-log1p.f32N/A
lower-*.f32N/A
lower-neg.f32N/A
lower-log1p.f3298.4
Applied rewrites98.4%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
count-2-revN/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-*l*N/A
lower-fma.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
*-commutativeN/A
lower-*.f3298.5
Applied rewrites98.5%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
lower-fma.f3287.5
Applied rewrites87.5%
lift-fma.f32N/A
lift-*.f32N/A
associate-*r*N/A
*-commutativeN/A
lift-pow.f32N/A
unpow2N/A
cube-unmultN/A
lift-cbrt.f32N/A
rem-cube-cbrtN/A
lift-*.f32N/A
*-commutativeN/A
distribute-lft-outN/A
lower-*.f32N/A
lower-+.f3287.5
Applied rewrites87.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{u1} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Initial program 57.9%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lift--.f32N/A
flip--N/A
associate-/r/N/A
log-prodN/A
lower-+.f32N/A
log-recN/A
lower-neg.f32N/A
metadata-evalN/A
fp-cancel-sub-sign-invN/A
lower-log1p.f32N/A
lower-*.f32N/A
lower-neg.f32N/A
lower-log1p.f3298.4
Applied rewrites98.4%
Taylor expanded in u1 around 0
lower-sqrt.f3276.2
Applied rewrites76.2%
herbie shell --seed 2024358
(FPCore (cosTheta_i u1 u2)
:name "Beckmann Sample, near normal, slope_y"
:precision binary32
:pre (and (and (and (> cosTheta_i 0.9999) (<= cosTheta_i 1.0)) (and (<= 2.328306437e-10 u1) (<= u1 1.0))) (and (<= 2.328306437e-10 u2) (<= u2 1.0)))
(* (sqrt (- (log (- 1.0 u1)))) (sin (* (* 2.0 (PI)) u2))))