
(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
(let* ((t_0 (- 1.0 (* u1 u1))) (t_1 (sin (* (* 2.0 (PI)) u2))))
(if (<= (- (log (- 1.0 u1))) 0.03200000151991844)
(*
(sqrt
(-
(*
(- (* (- (* (- (* -0.25 u1) 0.3333333333333333) u1) 0.5) u1) 1.0)
u1)))
t_1)
(* (sqrt (- (log t_0) (log (* t_0 (- 1.0 u1))))) t_1))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := 1 - u1 \cdot u1\\
t_1 := \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\mathbf{if}\;-\log \left(1 - u1\right) \leq 0.03200000151991844:\\
\;\;\;\;\sqrt{-\left(\left(\left(-0.25 \cdot u1 - 0.3333333333333333\right) \cdot u1 - 0.5\right) \cdot u1 - 1\right) \cdot u1} \cdot t\_1\\
\mathbf{else}:\\
\;\;\;\;\sqrt{\log t\_0 - \log \left(t\_0 \cdot \left(1 - u1\right)\right)} \cdot t\_1\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) < 0.0320000015Initial program 50.3%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
lower--.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower--.f32N/A
*-commutativeN/A
lower-*.f32N/A
metadata-evalN/A
distribute-lft-neg-inN/A
lower--.f32N/A
distribute-lft-neg-inN/A
metadata-evalN/A
lower-*.f3298.2
Applied rewrites98.2%
if 0.0320000015 < (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) Initial program 97.2%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lift--.f32N/A
flip--N/A
associate-/r/N/A
flip-+N/A
lift--.f32N/A
frac-timesN/A
log-divN/A
lower--.f32N/A
lower-log.f32N/A
lower-*.f32N/A
metadata-evalN/A
lower--.f32N/A
lower-*.f32N/A
lower-log.f32N/A
Applied rewrites97.8%
lift-*.f32N/A
*-lft-identity97.8
Applied rewrites97.8%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (- (log (- 1.0 u1)))) (t_1 (sin (* (* 2.0 (PI)) u2))))
(if (<= t_0 0.03999999910593033)
(*
(sqrt
(-
(*
(- (* (- (* (- (* -0.25 u1) 0.3333333333333333) u1) 0.5) u1) 1.0)
u1)))
t_1)
(* (sqrt t_0) t_1))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := -\log \left(1 - u1\right)\\
t_1 := \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\mathbf{if}\;t\_0 \leq 0.03999999910593033:\\
\;\;\;\;\sqrt{-\left(\left(\left(-0.25 \cdot u1 - 0.3333333333333333\right) \cdot u1 - 0.5\right) \cdot u1 - 1\right) \cdot u1} \cdot t\_1\\
\mathbf{else}:\\
\;\;\;\;\sqrt{t\_0} \cdot t\_1\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) < 0.0399999991Initial program 50.5%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
lower--.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower--.f32N/A
*-commutativeN/A
lower-*.f32N/A
metadata-evalN/A
distribute-lft-neg-inN/A
lower--.f32N/A
distribute-lft-neg-inN/A
metadata-evalN/A
lower-*.f3298.2
Applied rewrites98.2%
if 0.0399999991 < (neg.f32 (log.f32 (-.f32 #s(literal 1 binary32) u1))) Initial program 97.4%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(if (<= (- 1.0 u1) 0.9480000138282776)
(* (* (* (PI) u2) 2.0) (sqrt (- (log (- 1.0 u1)))))
(*
(sqrt
(-
(*
(- (* (- (* (- (* -0.25 u1) 0.3333333333333333) u1) 0.5) u1) 1.0)
u1)))
(sin (* (* 2.0 (PI)) u2)))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u1 \leq 0.9480000138282776:\\
\;\;\;\;\left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right) \cdot \sqrt{-\log \left(1 - u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\left(\left(\left(-0.25 \cdot u1 - 0.3333333333333333\right) \cdot u1 - 0.5\right) \cdot u1 - 1\right) \cdot u1} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.948000014Initial program 97.6%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3297.3
Applied rewrites97.3%
Taylor expanded in u1 around 0
lower-sqrt.f3237.5
Applied rewrites37.5%
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
lower-log.f32N/A
lower--.f3287.3
Applied rewrites87.3%
if 0.948000014 < (-.f32 #s(literal 1 binary32) u1) Initial program 51.1%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
lower--.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower--.f32N/A
*-commutativeN/A
lower-*.f32N/A
metadata-evalN/A
distribute-lft-neg-inN/A
lower--.f32N/A
distribute-lft-neg-inN/A
metadata-evalN/A
lower-*.f3298.1
Applied rewrites98.1%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(if (<= (- 1.0 u1) 0.9750000238418579)
(* (* (* (PI) u2) 2.0) (sqrt (- (log (- 1.0 u1)))))
(*
(sqrt (- (* (- (* (- (* -0.3333333333333333 u1) 0.5) u1) 1.0) u1)))
(sin (* (* 2.0 (PI)) u2)))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u1 \leq 0.9750000238418579:\\
\;\;\;\;\left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right) \cdot \sqrt{-\log \left(1 - u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\left(\left(-0.3333333333333333 \cdot u1 - 0.5\right) \cdot u1 - 1\right) \cdot u1} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.975000024Initial program 97.0%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3296.2
Applied rewrites96.2%
Taylor expanded in u1 around 0
lower-sqrt.f3239.5
Applied rewrites39.5%
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
lower-log.f32N/A
lower--.f3286.6
Applied rewrites86.6%
if 0.975000024 < (-.f32 #s(literal 1 binary32) u1) Initial program 49.7%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
lower--.f32N/A
*-commutativeN/A
lower-*.f32N/A
metadata-evalN/A
distribute-lft-neg-inN/A
*-commutativeN/A
distribute-lft-neg-inN/A
lower--.f32N/A
distribute-lft-neg-inN/A
*-commutativeN/A
distribute-lft-neg-inN/A
metadata-evalN/A
lower-*.f3297.7
Applied rewrites97.7%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= (- 1.0 u1) 0.9879999756813049) (* (* (* (PI) u2) 2.0) (sqrt (- (log (- 1.0 u1))))) (* (sqrt (- (* (- (* -0.5 u1) 1.0) u1))) (sin (* (* 2.0 (PI)) u2)))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u1 \leq 0.9879999756813049:\\
\;\;\;\;\left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right) \cdot \sqrt{-\log \left(1 - u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\left(-0.5 \cdot u1 - 1\right) \cdot u1} \cdot \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.987999976Initial program 95.7%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3295.0
Applied rewrites95.0%
Taylor expanded in u1 around 0
lower-sqrt.f3242.3
Applied rewrites42.3%
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
lower-log.f32N/A
lower--.f3284.0
Applied rewrites84.0%
if 0.987999976 < (-.f32 #s(literal 1 binary32) u1) Initial program 47.3%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
metadata-evalN/A
distribute-lft-neg-inN/A
*-commutativeN/A
distribute-lft-neg-inN/A
lower--.f32N/A
distribute-lft-neg-inN/A
*-commutativeN/A
distribute-lft-neg-inN/A
metadata-evalN/A
lower-*.f3296.8
Applied rewrites96.8%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= (- 1.0 u1) 0.9980999827384949) (* (* (* (PI) u2) 2.0) (sqrt (- (log (- 1.0 u1))))) (* (sqrt u1) (sin (* (PI) (+ u2 u2))))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u1 \leq 0.9980999827384949:\\
\;\;\;\;\left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right) \cdot \sqrt{-\log \left(1 - u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin \left(\mathsf{PI}\left(\right) \cdot \left(u2 + u2\right)\right)\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u1) < 0.998099983Initial program 93.6%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3292.5
Applied rewrites92.5%
Taylor expanded in u1 around 0
lower-sqrt.f3246.0
Applied rewrites46.0%
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
lower-log.f32N/A
lower--.f3279.4
Applied rewrites79.4%
if 0.998099983 < (-.f32 #s(literal 1 binary32) u1) Initial program 43.9%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3241.0
Applied rewrites41.0%
Taylor expanded in u1 around 0
lower-sqrt.f3288.2
Applied rewrites88.2%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
count-2-revN/A
distribute-lft-inN/A
distribute-rgt-outN/A
lower-*.f32N/A
lower-+.f3288.2
Applied rewrites88.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (sin (* (PI) (+ u2 u2)))))
\begin{array}{l}
\\
\sqrt{u1} \cdot \sin \left(\mathsf{PI}\left(\right) \cdot \left(u2 + u2\right)\right)
\end{array}
Initial program 56.3%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3253.9
Applied rewrites53.9%
Taylor expanded in u1 around 0
lower-sqrt.f3277.7
Applied rewrites77.7%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
count-2-revN/A
distribute-lft-inN/A
distribute-rgt-outN/A
lower-*.f32N/A
lower-+.f3277.7
Applied rewrites77.7%
(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 56.3%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3253.9
Applied rewrites53.9%
Taylor expanded in u1 around 0
lower-sqrt.f3277.7
Applied rewrites77.7%
Taylor expanded in u2 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3266.6
Applied rewrites66.6%
Applied rewrites66.6%
(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 56.3%
lift-neg.f32N/A
lift-log.f32N/A
neg-logN/A
lower-log.f32N/A
lower-/.f3253.9
Applied rewrites53.9%
Taylor expanded in u1 around 0
lower-sqrt.f3277.7
Applied rewrites77.7%
Taylor expanded in u2 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3266.6
Applied rewrites66.6%
herbie shell --seed 2024333
(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))))