
(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 7 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
(if (<= (- 1.0 u1) 0.9965000152587891)
(*
(sin (/ (* (* 2.0 u2) (pow (PI) 3.0)) (* (PI) (PI))))
(sqrt (- (log (- 1.0 u1)))))
(* (sin (* (* 2.0 (PI)) u2)) (sqrt (- (* (- (/ -1.0 u1) 0.5) (* u1 u1)))))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u1 \leq 0.9965000152587891:\\
\;\;\;\;\sin \left(\frac{\left(2 \cdot u2\right) \cdot {\mathsf{PI}\left(\right)}^{3}}{\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)}\right) \cdot \sqrt{-\log \left(1 - u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right) \cdot \sqrt{-\left(\frac{-1}{u1} - 0.5\right) \cdot \left(u1 \cdot u1\right)}\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.99650002Initial program 94.5%
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
associate-*l*N/A
+-lft-identityN/A
flip3-+N/A
metadata-evalN/A
lift-PI.f32N/A
add-cbrt-cubeN/A
rem-cube-cbrtN/A
+-lft-identityN/A
metadata-evalN/A
+-lft-identityN/A
distribute-rgt-out--N/A
lift-PI.f32N/A
lift-PI.f32N/A
--rgt-identity-revN/A
associate-*l/N/A
Applied rewrites94.7%
if 0.99650002 < (-.f32 #s(literal 1 binary32) u1) Initial program 43.9%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f3241.5
Applied rewrites40.6%
Applied rewrites97.6%
Taylor expanded in u1 around inf
Applied rewrites97.7%
Final simplification97.0%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (PI))))
(if (<= (- 1.0 u1) 0.9965000152587891)
(* (* (* (sin t_0) (cos t_0)) 2.0) (sqrt (- (log (- 1.0 u1)))))
(*
(sin (* (* 2.0 (PI)) u2))
(sqrt (- (* (- (/ -1.0 u1) 0.5) (* u1 u1))))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \mathsf{PI}\left(\right)\\
\mathbf{if}\;1 - u1 \leq 0.9965000152587891:\\
\;\;\;\;\left(\left(\sin t\_0 \cdot \cos t\_0\right) \cdot 2\right) \cdot \sqrt{-\log \left(1 - u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right) \cdot \sqrt{-\left(\frac{-1}{u1} - 0.5\right) \cdot \left(u1 \cdot u1\right)}\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.99650002Initial program 94.5%
lift-sin.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
sin-2N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-cos.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-sin.f32N/A
*-commutativeN/A
lower-*.f3294.6
Applied rewrites94.6%
if 0.99650002 < (-.f32 #s(literal 1 binary32) u1) Initial program 43.9%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f3240.0
Applied rewrites41.3%
Applied rewrites97.6%
Taylor expanded in u1 around inf
Applied rewrites97.7%
Final simplification97.0%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (sin (* (* 2.0 (PI)) u2))))
(if (<= (- 1.0 u1) 0.9965000152587891)
(* t_0 (sqrt (- (log (- 1.0 u1)))))
(* t_0 (sqrt (- (* (- (/ -1.0 u1) 0.5) (* u1 u1))))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\mathbf{if}\;1 - u1 \leq 0.9965000152587891:\\
\;\;\;\;t\_0 \cdot \sqrt{-\log \left(1 - u1\right)}\\
\mathbf{else}:\\
\;\;\;\;t\_0 \cdot \sqrt{-\left(\frac{-1}{u1} - 0.5\right) \cdot \left(u1 \cdot u1\right)}\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.99650002Initial program 94.5%
if 0.99650002 < (-.f32 #s(literal 1 binary32) u1) Initial program 43.9%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f3239.7
Applied rewrites40.4%
Applied rewrites97.6%
Taylor expanded in u1 around inf
Applied rewrites97.7%
Final simplification96.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* (* 2.0 (PI)) u2)) (sqrt (- (* (- (/ -1.0 u1) 0.5) (* u1 u1))))))
\begin{array}{l}
\\
\sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right) \cdot \sqrt{-\left(\frac{-1}{u1} - 0.5\right) \cdot \left(u1 \cdot u1\right)}
\end{array}
Initial program 56.0%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f3237.9
Applied rewrites38.6%
Applied rewrites88.4%
Taylor expanded in u1 around inf
Applied rewrites88.5%
Final simplification88.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (* (- -1.0 (* 0.5 u1)) u1))) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\sqrt{-\left(-1 - 0.5 \cdot u1\right) \cdot u1} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Initial program 56.0%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f3238.2
Applied rewrites36.8%
Applied rewrites88.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (sin (* (* u2 (PI)) 2.0))))
\begin{array}{l}
\\
\sqrt{u1} \cdot \sin \left(\left(u2 \cdot \mathsf{PI}\left(\right)\right) \cdot 2\right)
\end{array}
Initial program 56.0%
lift-log.f32N/A
lift--.f32N/A
flip3--N/A
log-divN/A
lower--.f32N/A
metadata-evalN/A
sub-negN/A
cube-negN/A
metadata-evalN/A
metadata-evalN/A
lower-log1p.f32N/A
lower-pow.f32N/A
lower-neg.f32N/A
metadata-evalN/A
lower-log1p.f32N/A
*-lft-identityN/A
lower-fma.f3225.1
Applied rewrites25.1%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
lower-sqrt.f3277.7
Applied rewrites77.7%
Final simplification77.7%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (* (sqrt u1) 2.0) (* u2 (PI))))
\begin{array}{l}
\\
\left(\sqrt{u1} \cdot 2\right) \cdot \left(u2 \cdot \mathsf{PI}\left(\right)\right)
\end{array}
Initial program 56.0%
lift-log.f32N/A
lift--.f32N/A
flip3--N/A
log-divN/A
lower--.f32N/A
metadata-evalN/A
sub-negN/A
cube-negN/A
metadata-evalN/A
metadata-evalN/A
lower-log1p.f32N/A
lower-pow.f32N/A
lower-neg.f32N/A
metadata-evalN/A
lower-log1p.f32N/A
*-lft-identityN/A
lower-fma.f3225.2
Applied rewrites25.1%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
lower-sqrt.f3277.7
Applied rewrites77.7%
Taylor expanded in u2 around 0
Applied rewrites66.0%
Final simplification66.0%
herbie shell --seed 2024312
(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))))