
(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 9 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 (* (pow (pow (- (log1p (- u1))) 2.0) 0.25) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
{\left({\left(-\mathsf{log1p}\left(-u1\right)\right)}^{2}\right)}^{0.25} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Initial program 57.5%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow-prod-downN/A
lower-pow.f32N/A
pow2N/A
lower-pow.f32N/A
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.f32N/A
metadata-eval98.5
Applied rewrites98.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(if (<= (log (- 1.0 u1)) -0.07000000029802322)
(* (* (* (PI) u2) 2.0) (sqrt (- (log1p (- u1)))))
(*
(sqrt (* (fma (fma 0.3333333333333333 u1 0.5) u1 1.0) u1))
(sin (* (* 2.0 (PI)) u2)))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\log \left(1 - u1\right) \leq -0.07000000029802322:\\
\;\;\;\;\left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right) \cdot \sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\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}
\end{array}
if (log.f32 (-.f32 #s(literal 1 binary32) u1)) < -0.0700000003Initial program 97.7%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3297.4
Applied rewrites97.4%
Taylor expanded in u2 around 0
associate-*r*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
lower-sqrt.f32N/A
log-recN/A
lower-neg.f32N/A
*-lft-identityN/A
fp-cancel-sub-sign-invN/A
metadata-evalN/A
mul-1-negN/A
lower-log1p.f32N/A
lower-neg.f3285.9
Applied rewrites85.9%
if -0.0700000003 < (log.f32 (-.f32 #s(literal 1 binary32) u1)) Initial program 51.1%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
lower-fma.f3297.5
Applied rewrites97.5%
(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 57.5%
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
(if (<= u1 0.06800000369548798)
(*
(sqrt (* (fma (fma (fma 0.25 u1 0.3333333333333333) u1 0.5) u1 1.0) u1))
(sin (* (* 2.0 (PI)) u2)))
(* (* (* (PI) u2) 2.0) (sqrt (- (log1p (- u1)))))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u1 \leq 0.06800000369548798:\\
\;\;\;\;\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)\\
\mathbf{else}:\\
\;\;\;\;\left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right) \cdot \sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\end{array}
\end{array}
if u1 < 0.0680000037Initial program 51.1%
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.f3298.1
Applied rewrites98.1%
if 0.0680000037 < u1 Initial program 97.7%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3297.4
Applied rewrites97.4%
Taylor expanded in u2 around 0
associate-*r*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
lower-sqrt.f32N/A
log-recN/A
lower-neg.f32N/A
*-lft-identityN/A
fp-cancel-sub-sign-invN/A
metadata-evalN/A
mul-1-negN/A
lower-log1p.f32N/A
lower-neg.f3285.9
Applied rewrites85.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= u2 0.0006000000284984708) (* (* (* (PI) u2) 2.0) (sqrt (- (log1p (- u1))))) (* (sqrt (* (fma 0.5 u1 1.0) u1)) (sin (* (* 2.0 (PI)) u2)))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u2 \leq 0.0006000000284984708:\\
\;\;\;\;\left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right) \cdot \sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{\mathsf{fma}\left(0.5, u1, 1\right) \cdot u1} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\end{array}
\end{array}
if u2 < 6.00000028e-4Initial program 55.5%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3253.3
Applied rewrites53.3%
Taylor expanded in u2 around 0
associate-*r*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
lower-sqrt.f32N/A
log-recN/A
lower-neg.f32N/A
*-lft-identityN/A
fp-cancel-sub-sign-invN/A
metadata-evalN/A
mul-1-negN/A
lower-log1p.f32N/A
lower-neg.f3297.4
Applied rewrites97.4%
if 6.00000028e-4 < u2 Initial program 60.8%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
lower-fma.f3288.6
Applied rewrites88.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= u2 0.0017000000225380063) (* (* (* (PI) u2) 2.0) (sqrt (- (log1p (- u1))))) (* (sqrt u1) (sin (* (* 2.0 (PI)) u2)))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u2 \leq 0.0017000000225380063:\\
\;\;\;\;\left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right) \cdot \sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\end{array}
\end{array}
if u2 < 0.00170000002Initial program 55.8%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3253.5
Applied rewrites53.5%
Taylor expanded in u2 around 0
associate-*r*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
lower-sqrt.f32N/A
log-recN/A
lower-neg.f32N/A
*-lft-identityN/A
fp-cancel-sub-sign-invN/A
metadata-evalN/A
mul-1-negN/A
lower-log1p.f32N/A
lower-neg.f3295.9
Applied rewrites95.9%
if 0.00170000002 < u2 Initial program 61.3%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3258.2
Applied rewrites58.2%
Taylor expanded in u1 around 0
lower-sqrt.f3274.8
Applied rewrites74.8%
(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 57.5%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3255.0
Applied rewrites55.0%
Taylor expanded in u1 around 0
lower-sqrt.f3276.9
Applied rewrites76.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (pow (* u1 u1) 0.25) (* (* (PI) u2) 2.0)))
\begin{array}{l}
\\
{\left(u1 \cdot u1\right)}^{0.25} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right)
\end{array}
Initial program 57.5%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3255.0
Applied rewrites55.0%
Taylor expanded in u1 around 0
lower-sqrt.f3276.9
Applied rewrites76.9%
Taylor expanded in u2 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3266.4
Applied rewrites66.4%
Applied rewrites66.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (* (* (PI) u2) 2.0)))
\begin{array}{l}
\\
\sqrt{u1} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right)
\end{array}
Initial program 57.5%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3255.0
Applied rewrites55.0%
Taylor expanded in u1 around 0
lower-sqrt.f3276.9
Applied rewrites76.9%
Taylor expanded in u2 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3266.4
Applied rewrites66.4%
herbie shell --seed 2024352
(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))))