
(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 (* (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 56.5%
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.f3298.5
Applied rewrites98.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(if (<= u1 0.1899999976158142)
(*
(sqrt (* (fma (fma (fma 0.25 u1 0.3333333333333333) u1 0.5) u1 1.0) u1))
(sin (* (* 2.0 (PI)) u2)))
(*
(* u2 (* 2.0 (* (sqrt 2.0) (PI))))
(sqrt (log (sqrt (/ 1.0 (- 1.0 u1))))))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u1 \leq 0.1899999976158142:\\
\;\;\;\;\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(u2 \cdot \left(2 \cdot \left(\sqrt{2} \cdot \mathsf{PI}\left(\right)\right)\right)\right) \cdot \sqrt{\log \left(\sqrt{\frac{1}{1 - u1}}\right)}\\
\end{array}
\end{array}
if u1 < 0.189999998Initial program 52.0%
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.f3297.0
Applied rewrites97.0%
if 0.189999998 < u1 Initial program 98.5%
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-eval97.7
Applied rewrites97.7%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*l*N/A
associate-*r*N/A
*-commutativeN/A
associate-*r*N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-sqrt.f32N/A
lower-PI.f32N/A
lower-sqrt.f32N/A
Applied rewrites89.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (* (fma (fma (fma 0.25 u1 0.3333333333333333) u1 0.5) u1 1.0) u1)) (sin (* (* 2.0 (PI)) 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 \sin \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right)
\end{array}
Initial program 56.5%
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.f3292.6
Applied rewrites92.6%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (sqrt (/ 1.0 u1))))
(if (<= u2 0.00019999999494757503)
(*
(fma
(fma
(fma
(* (- 0.25 (/ 0.0625 u1)) (sqrt u1))
0.5
(* 0.16666666666666666 t_0))
u1
(* t_0 0.25))
(* u1 u1)
(sqrt u1))
(* (* (PI) u2) 2.0))
(* (sqrt (* (fma 0.5 u1 1.0) u1)) (sin (* (* 2.0 (PI)) u2))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\frac{1}{u1}}\\
\mathbf{if}\;u2 \leq 0.00019999999494757503:\\
\;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(0.25 - \frac{0.0625}{u1}\right) \cdot \sqrt{u1}, 0.5, 0.16666666666666666 \cdot t\_0\right), u1, t\_0 \cdot 0.25\right), u1 \cdot u1, \sqrt{u1}\right) \cdot \left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\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 < 1.99999995e-4Initial program 58.5%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow2N/A
lower-pow.f32N/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-eval98.0
Applied rewrites98.0%
Taylor expanded in u1 around 0
lower-sqrt.f3276.3
Applied rewrites76.3%
Taylor expanded in u2 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3276.3
Applied rewrites76.3%
Taylor expanded in u1 around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
Applied rewrites92.5%
if 1.99999995e-4 < u2 Initial program 53.4%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
lower-fma.f3286.9
Applied rewrites86.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (* (fma (fma 0.3333333333333333 u1 0.5) u1 1.0) u1)) (sin (* (* 2.0 (PI)) u2))))
\begin{array}{l}
\\
\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}
Initial program 56.5%
Taylor expanded in u1 around 0
*-commutativeN/A
lower-*.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
lower-fma.f3290.7
Applied rewrites90.7%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (sqrt (/ 1.0 u1))))
(if (<= u2 0.001500000013038516)
(*
(fma
(fma
(fma
(* (- 0.25 (/ 0.0625 u1)) (sqrt u1))
0.5
(* 0.16666666666666666 t_0))
u1
(* t_0 0.25))
(* u1 u1)
(sqrt u1))
(* (* (PI) u2) 2.0))
(* (sqrt u1) (sin (* (* 2.0 (PI)) u2))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\frac{1}{u1}}\\
\mathbf{if}\;u2 \leq 0.001500000013038516:\\
\;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\left(0.25 - \frac{0.0625}{u1}\right) \cdot \sqrt{u1}, 0.5, 0.16666666666666666 \cdot t\_0\right), u1, t\_0 \cdot 0.25\right), u1 \cdot u1, \sqrt{u1}\right) \cdot \left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\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 < 0.00150000001Initial program 57.5%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow2N/A
lower-pow.f32N/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-eval98.0
Applied rewrites98.0%
Taylor expanded in u1 around 0
lower-sqrt.f3276.4
Applied rewrites76.4%
Taylor expanded in u2 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3275.4
Applied rewrites75.4%
Taylor expanded in u1 around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
Applied rewrites90.8%
if 0.00150000001 < u2 Initial program 54.2%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow2N/A
lower-pow.f32N/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-eval97.4
Applied rewrites97.4%
Taylor expanded in u1 around 0
lower-sqrt.f3276.9
Applied rewrites76.9%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(if (<= u2 0.0010999999940395355)
(*
(fma
(fma (sqrt (/ 1.0 u1)) 0.25 (* 0.16666666666666666 (sqrt u1)))
(* u1 u1)
(sqrt u1))
(* (* (PI) u2) 2.0))
(* (sqrt u1) (sin (* (* 2.0 (PI)) u2)))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u2 \leq 0.0010999999940395355:\\
\;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(\sqrt{\frac{1}{u1}}, 0.25, 0.16666666666666666 \cdot \sqrt{u1}\right), u1 \cdot u1, \sqrt{u1}\right) \cdot \left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\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 < 0.0011Initial program 57.8%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow2N/A
lower-pow.f32N/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-eval98.0
Applied rewrites98.0%
Taylor expanded in u1 around 0
lower-sqrt.f3276.3
Applied rewrites76.3%
Taylor expanded in u2 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3275.8
Applied rewrites75.8%
Taylor expanded in u1 around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
lower-sqrt.f32N/A
lower-/.f32N/A
lower-*.f32N/A
lower-sqrt.f32N/A
unpow2N/A
lower-*.f32N/A
lower-sqrt.f3289.0
Applied rewrites89.0%
if 0.0011 < u2 Initial program 53.7%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow2N/A
lower-pow.f32N/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-eval97.4
Applied rewrites97.4%
Taylor expanded in u1 around 0
lower-sqrt.f3277.0
Applied rewrites77.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (fma (fma (sqrt (/ 1.0 u1)) 0.25 (* 0.16666666666666666 (sqrt u1))) (* u1 u1) (sqrt u1)) (* (* (PI) u2) 2.0)))
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(\sqrt{\frac{1}{u1}}, 0.25, 0.16666666666666666 \cdot \sqrt{u1}\right), u1 \cdot u1, \sqrt{u1}\right) \cdot \left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot 2\right)
\end{array}
Initial program 56.5%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow2N/A
lower-pow.f32N/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-eval97.8
Applied rewrites97.8%
Taylor expanded in u1 around 0
lower-sqrt.f3276.5
Applied rewrites76.5%
Taylor expanded in u2 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3265.4
Applied rewrites65.4%
Taylor expanded in u1 around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
lower-sqrt.f32N/A
lower-/.f32N/A
lower-*.f32N/A
lower-sqrt.f32N/A
unpow2N/A
lower-*.f32N/A
lower-sqrt.f3274.9
Applied rewrites74.9%
(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 56.5%
lift-sqrt.f32N/A
pow1/2N/A
sqr-powN/A
pow2N/A
lower-pow.f32N/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-eval97.8
Applied rewrites97.8%
Taylor expanded in u1 around 0
lower-sqrt.f3276.5
Applied rewrites76.5%
Taylor expanded in u2 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3265.4
Applied rewrites65.4%
herbie shell --seed 2024360
(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))))