
(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
(if (<= u1 0.03400000184774399)
(*
(sqrt (fma (* (fma (fma 0.25 u1 0.3333333333333333) u1 0.5) u1) u1 u1))
(sin (* (* (PI) 2.0) u2)))
(* (sqrt (- (log (- 1.0 u1)))) (sin (* (+ (PI) (PI)) u2)))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u1 \leq 0.03400000184774399:\\
\;\;\;\;\sqrt{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.25, u1, 0.3333333333333333\right), u1, 0.5\right) \cdot u1, u1, u1\right)} \cdot \sin \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\log \left(1 - u1\right)} \cdot \sin \left(\left(\mathsf{PI}\left(\right) + \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\end{array}
\end{array}
if u1 < 0.0340000018Initial program 53.1%
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.f3298.6
Applied rewrites98.6%
lift-*.f32N/A
lift-fma.f32N/A
lift-fma.f32N/A
lift-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
+-commutativeN/A
*-commutativeN/A
+-commutativeN/A
*-commutativeN/A
distribute-lft-inN/A
lower-fma.f32N/A
lower-*.f32N/A
*-commutativeN/A
+-commutativeN/A
*-commutativeN/A
+-commutativeN/A
Applied rewrites98.6%
Applied rewrites98.6%
if 0.0340000018 < u1 Initial program 98.0%
lift-PI.f32N/A
lift-*.f32N/A
count-2-revN/A
lower-+.f32N/A
lift-PI.f32N/A
lift-PI.f3298.0
Applied rewrites98.0%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (log (- 1.0 u1))))
(if (<= t_0 -0.00044999999227002263)
(* (sqrt (- t_0)) (* (* (PI) 2.0) u2))
(* (sqrt u1) (sin (* (+ (PI) (PI)) u2))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \log \left(1 - u1\right)\\
\mathbf{if}\;t\_0 \leq -0.00044999999227002263:\\
\;\;\;\;\sqrt{-t\_0} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin \left(\left(\mathsf{PI}\left(\right) + \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\end{array}
\end{array}
if (log.f32 (-.f32 #s(literal 1 binary32) u1)) < -4.49999992e-4Initial program 92.1%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-PI.f3279.9
Applied rewrites79.9%
if -4.49999992e-4 < (log.f32 (-.f32 #s(literal 1 binary32) u1)) Initial program 41.6%
Taylor expanded in u1 around 0
Applied rewrites91.3%
lift-PI.f32N/A
lift-*.f32N/A
count-2-revN/A
lift-+.f32N/A
lift-PI.f32N/A
lift-PI.f3291.3
Applied rewrites91.3%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(if (<= u1 0.05999999865889549)
(*
(sqrt (* (fma (fma (fma 0.25 u1 0.3333333333333333) u1 0.5) u1 1.0) u1))
(sin (* (+ (PI) (PI)) u2)))
(* (sqrt (- (log (- 1.0 u1)))) (* (* (PI) 2.0) u2))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u1 \leq 0.05999999865889549:\\
\;\;\;\;\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(\mathsf{PI}\left(\right) + \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\log \left(1 - u1\right)} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right)\\
\end{array}
\end{array}
if u1 < 0.0599999987Initial program 54.3%
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.f3298.4
Applied rewrites98.4%
lift-PI.f32N/A
lift-*.f32N/A
count-2-revN/A
lift-+.f32N/A
lift-PI.f32N/A
lift-PI.f3298.4
Applied rewrites98.4%
if 0.0599999987 < u1 Initial program 98.1%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-PI.f3286.6
Applied rewrites86.6%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(if (<= u1 0.030500000342726707)
(*
(sqrt (* (fma (fma 0.3333333333333333 u1 0.5) u1 1.0) u1))
(sin (* (* 2.0 (PI)) u2)))
(* (sqrt (- (log (- 1.0 u1)))) (* (* (PI) 2.0) u2))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u1 \leq 0.030500000342726707:\\
\;\;\;\;\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)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\log \left(1 - u1\right)} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right)\\
\end{array}
\end{array}
if u1 < 0.0305000003Initial program 52.7%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
lower-fma.f3297.8
Applied rewrites97.8%
if 0.0305000003 < u1 Initial program 97.8%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-PI.f3287.0
Applied rewrites87.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= u1 0.009999999776482582) (* (sqrt (* (fma 0.5 u1 1.0) u1)) (sin (* (+ (PI) (PI)) u2))) (* (sqrt (- (log (- 1.0 u1)))) (* (* (PI) 2.0) u2))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u1 \leq 0.009999999776482582:\\
\;\;\;\;\sqrt{\mathsf{fma}\left(0.5, u1, 1\right) \cdot u1} \cdot \sin \left(\left(\mathsf{PI}\left(\right) + \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\log \left(1 - u1\right)} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right)\\
\end{array}
\end{array}
if u1 < 0.00999999978Initial program 49.5%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
lower-fma.f3296.9
Applied rewrites96.9%
lift-PI.f32N/A
lift-*.f32N/A
count-2-revN/A
lift-+.f32N/A
lift-PI.f32N/A
lift-PI.f3296.9
Applied rewrites96.9%
if 0.00999999978 < u1 Initial program 96.4%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-PI.f3284.2
Applied rewrites84.2%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(if (<= u2 0.0020000000949949026)
(*
(sqrt (* (fma (fma (fma 0.25 u1 0.3333333333333333) u1 0.5) u1 1.0) u1))
(* (* (PI) 2.0) u2))
(* (sqrt u1) (sin (* (+ (PI) (PI)) u2)))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u2 \leq 0.0020000000949949026:\\
\;\;\;\;\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 \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin \left(\left(\mathsf{PI}\left(\right) + \mathsf{PI}\left(\right)\right) \cdot u2\right)\\
\end{array}
\end{array}
if u2 < 0.00200000009Initial program 60.7%
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.f3291.8
Applied rewrites91.8%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-PI.f3289.9
Applied rewrites89.9%
if 0.00200000009 < u2 Initial program 57.6%
Taylor expanded in u1 around 0
Applied rewrites78.9%
lift-PI.f32N/A
lift-*.f32N/A
count-2-revN/A
lift-+.f32N/A
lift-PI.f32N/A
lift-PI.f3278.9
Applied rewrites78.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (* (fma (fma (fma 0.25 u1 0.3333333333333333) u1 0.5) u1 1.0) u1)) (* (* (PI) 2.0) 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 \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right)
\end{array}
Initial program 59.8%
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.f3293.2
Applied rewrites93.2%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-PI.f3276.6
Applied rewrites76.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (* (fma 0.5 u1 1.0) u1)) (* (* (PI) 2.0) u2)))
\begin{array}{l}
\\
\sqrt{\mathsf{fma}\left(0.5, u1, 1\right) \cdot u1} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right)
\end{array}
Initial program 59.8%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
lower-fma.f3287.6
Applied rewrites87.6%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-PI.f3272.9
Applied rewrites72.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (* (* (PI) 2.0) u2)))
\begin{array}{l}
\\
\sqrt{u1} \cdot \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right)
\end{array}
Initial program 59.8%
Taylor expanded in u1 around 0
Applied rewrites76.3%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*l*N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-PI.f3265.9
Applied rewrites65.9%
herbie shell --seed 2025043
(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))))