
(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 6 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 (sqrt (PI))))
(if (<= (- 1.0 u1) 0.9998499751091003)
(*
(sqrt (- (log (- 1.0 u1))))
(* (* (cos (* u2 (PI))) (sin (* (* u2 t_0) t_0))) 2.0))
(* (sin (* (* u2 2.0) (PI))) (sqrt u1)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\mathsf{PI}\left(\right)}\\
\mathbf{if}\;1 - u1 \leq 0.9998499751091003:\\
\;\;\;\;\sqrt{-\log \left(1 - u1\right)} \cdot \left(\left(\cos \left(u2 \cdot \mathsf{PI}\left(\right)\right) \cdot \sin \left(\left(u2 \cdot t\_0\right) \cdot t\_0\right)\right) \cdot 2\right)\\
\mathbf{else}:\\
\;\;\;\;\sin \left(\left(u2 \cdot 2\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.999849975Initial program 87.3%
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-*.f3287.3
Applied rewrites87.3%
lift-*.f32N/A
lift-PI.f32N/A
add-sqr-sqrtN/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-sqrt.f32N/A
lift-PI.f32N/A
lower-sqrt.f3287.3
Applied rewrites87.3%
if 0.999849975 < (-.f32 #s(literal 1 binary32) u1) Initial program 37.0%
Taylor expanded in u1 around 0
*-commutativeN/A
unpow2N/A
rem-square-sqrtN/A
mul-1-negN/A
lower-neg.f32N/A
lower-sqrt.f324.2
Applied rewrites4.2%
Applied rewrites92.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (PI))))
(if (<= (- 1.0 u1) 0.9998499751091003)
(* (sqrt (- (log (- 1.0 u1)))) (* (* (cos t_0) (sin t_0)) 2.0))
(* (sin (* (* u2 2.0) (PI))) (sqrt u1)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \mathsf{PI}\left(\right)\\
\mathbf{if}\;1 - u1 \leq 0.9998499751091003:\\
\;\;\;\;\sqrt{-\log \left(1 - u1\right)} \cdot \left(\left(\cos t\_0 \cdot \sin t\_0\right) \cdot 2\right)\\
\mathbf{else}:\\
\;\;\;\;\sin \left(\left(u2 \cdot 2\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.999849975Initial program 87.3%
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-*.f3287.3
Applied rewrites87.3%
if 0.999849975 < (-.f32 #s(literal 1 binary32) u1) Initial program 37.0%
Taylor expanded in u1 around 0
*-commutativeN/A
unpow2N/A
rem-square-sqrtN/A
mul-1-negN/A
lower-neg.f32N/A
lower-sqrt.f324.2
Applied rewrites4.2%
Applied rewrites92.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(if (<= (- (log (- 1.0 u1))) 0.0006900000153109431)
(* (sin (* (* u2 2.0) (PI))) (sqrt u1))
(*
(* 2.0 (* (* (sqrt 2.0) (PI)) u2))
(sqrt (log (sqrt (/ 1.0 (- 1.0 u1))))))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;-\log \left(1 - u1\right) \leq 0.0006900000153109431:\\
\;\;\;\;\sin \left(\left(u2 \cdot 2\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \sqrt{u1}\\
\mathbf{else}:\\
\;\;\;\;\left(2 \cdot \left(\left(\sqrt{2} \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\right) \cdot \sqrt{\log \left(\sqrt{\frac{1}{1 - u1}}\right)}\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) < 6.90000015e-4Initial program 41.9%
Taylor expanded in u1 around 0
*-commutativeN/A
unpow2N/A
rem-square-sqrtN/A
mul-1-negN/A
lower-neg.f32N/A
lower-sqrt.f324.1
Applied rewrites4.1%
Applied rewrites89.5%
if 6.90000015e-4 < (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) Initial program 91.4%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
inv-powN/A
sqr-powN/A
log-prodN/A
lower-+.f32N/A
lower-log.f32N/A
lower-pow.f32N/A
metadata-evalN/A
lower-log.f32N/A
lower-pow.f32N/A
metadata-eval87.6
Applied rewrites87.6%
Taylor expanded in u2 around 0
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-sqrt.f32N/A
lower-PI.f32N/A
lower-sqrt.f32N/A
lower-log.f32N/A
lower-sqrt.f32N/A
lower-/.f32N/A
lower--.f3275.1
Applied rewrites75.1%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= (- 1.0 u1) 0.9998499751091003) (* (sqrt (- (log (- 1.0 u1)))) (sin (* (PI) (+ u2 u2)))) (* (sin (* (* u2 2.0) (PI))) (sqrt u1))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u1 \leq 0.9998499751091003:\\
\;\;\;\;\sqrt{-\log \left(1 - u1\right)} \cdot \sin \left(\mathsf{PI}\left(\right) \cdot \left(u2 + u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin \left(\left(u2 \cdot 2\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.999849975Initial program 87.3%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-*l*N/A
associate-*l*N/A
lower-*.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lower-*.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-cbrt.f3287.2
Applied rewrites87.2%
lift-*.f32N/A
lift-*.f32N/A
associate-*r*N/A
lift-*.f32N/A
associate-*r*N/A
lift-pow.f32N/A
pow-plusN/A
lift-cbrt.f32N/A
metadata-evalN/A
rem-cube-cbrtN/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
count-2N/A
lift-*.f32N/A
lift-*.f32N/A
distribute-rgt-outN/A
lower-*.f32N/A
lower-+.f3287.3
Applied rewrites87.3%
if 0.999849975 < (-.f32 #s(literal 1 binary32) u1) Initial program 37.0%
Taylor expanded in u1 around 0
*-commutativeN/A
unpow2N/A
rem-square-sqrtN/A
mul-1-negN/A
lower-neg.f32N/A
lower-sqrt.f324.2
Applied rewrites4.2%
Applied rewrites92.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* (* u2 2.0) (PI))) (sqrt u1)))
\begin{array}{l}
\\
\sin \left(\left(u2 \cdot 2\right) \cdot \mathsf{PI}\left(\right)\right) \cdot \sqrt{u1}
\end{array}
Initial program 55.1%
Taylor expanded in u1 around 0
*-commutativeN/A
unpow2N/A
rem-square-sqrtN/A
mul-1-negN/A
lower-neg.f32N/A
lower-sqrt.f324.0
Applied rewrites4.0%
Applied rewrites79.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (* 2.0 (sqrt u1)) (* (PI) u2)))
\begin{array}{l}
\\
\left(2 \cdot \sqrt{u1}\right) \cdot \left(\mathsf{PI}\left(\right) \cdot u2\right)
\end{array}
Initial program 55.1%
Applied rewrites15.1%
Taylor expanded in u1 around 0
associate-*r*N/A
distribute-rgt-outN/A
+-commutativeN/A
lower-*.f32N/A
Applied rewrites79.0%
Taylor expanded in u2 around 0
associate-*r*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-sqrt.f32N/A
lower-log1p.f3267.9
Applied rewrites67.9%
Taylor expanded in u1 around 0
Applied rewrites67.9%
herbie shell --seed 2024323
(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))))