
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (sin (* (* 2.0 PI) u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-logf((1.0f - u1))) * sinf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(-log((single(1.0) - u1))) * sin(((single(2.0) * single(pi)) * u2)); end
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \sin \left(\left(2 \cdot \pi\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))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-logf((1.0f - u1))) * sinf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(-log((single(1.0) - u1))) * sin(((single(2.0) * single(pi)) * u2)); end
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \sin \left(\left(2 \cdot \pi\right) \cdot u2\right)
\end{array}
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (sin (cbrt (* (pow (* 2.0 PI) 3.0) (pow u2 3.0))))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf(cbrtf((powf((2.0f * ((float) M_PI)), 3.0f) * powf(u2, 3.0f))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(cbrt(Float32((Float32(Float32(2.0) * Float32(pi)) ^ Float32(3.0)) * (u2 ^ Float32(3.0)))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(\sqrt[3]{{\left(2 \cdot \pi\right)}^{3} \cdot {u2}^{3}}\right)
\end{array}
Initial program 57.2%
sub-neg57.2%
log1p-define98.4%
Simplified98.4%
add-cbrt-cube98.4%
add-cbrt-cube98.4%
cbrt-unprod98.5%
pow398.5%
pow398.5%
Applied egg-rr98.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (sin (* (* 2.0 PI) u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(\left(2 \cdot \pi\right) \cdot u2\right)
\end{array}
Initial program 57.2%
sub-neg57.2%
log1p-define98.4%
Simplified98.4%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* 2.0 (* PI u2))))
(if (<= (* (* 2.0 PI) u2) 0.006000000052154064)
(* (sqrt (- (log1p (- u1)))) t_0)
(* (sqrt u1) (sin t_0)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = 2.0f * (((float) M_PI) * u2);
float tmp;
if (((2.0f * ((float) M_PI)) * u2) <= 0.006000000052154064f) {
tmp = sqrtf(-log1pf(-u1)) * t_0;
} else {
tmp = sqrtf(u1) * sinf(t_0);
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(Float32(2.0) * Float32(Float32(pi) * u2)) tmp = Float32(0.0) if (Float32(Float32(Float32(2.0) * Float32(pi)) * u2) <= Float32(0.006000000052154064)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * t_0); else tmp = Float32(sqrt(u1) * sin(t_0)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 2 \cdot \left(\pi \cdot u2\right)\\
\mathbf{if}\;\left(2 \cdot \pi\right) \cdot u2 \leq 0.006000000052154064:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot t\_0\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin t\_0\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 0.00600000005Initial program 57.9%
sub-neg57.9%
log1p-define98.5%
Simplified98.5%
add-cbrt-cube98.5%
add-cbrt-cube98.5%
cbrt-unprod98.5%
pow398.5%
pow398.6%
Applied egg-rr98.6%
Taylor expanded in u2 around 0 96.9%
if 0.00600000005 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 55.8%
sub-neg55.8%
log1p-define98.1%
Simplified98.1%
Taylor expanded in u1 around 0 -0.0%
associate-*r*-0.0%
unpow2-0.0%
rem-square-sqrt3.6%
*-commutative3.6%
associate-*l*3.6%
*-commutative3.6%
mul-1-neg3.6%
Simplified3.6%
expm1-log1p-u3.6%
expm1-undefine3.6%
*-commutative3.6%
add-sqr-sqrt-0.0%
sqrt-unprod58.3%
sqr-neg58.3%
add-sqr-sqrt58.3%
*-commutative58.3%
associate-*r*58.3%
*-commutative58.3%
associate-*l*58.3%
Applied egg-rr58.3%
log1p-undefine58.3%
rem-exp-log58.3%
+-commutative58.3%
associate--l+76.5%
*-commutative76.5%
*-commutative76.5%
associate-*r*76.5%
metadata-eval76.5%
mul0-lft76.5%
distribute-rgt-in76.5%
+-rgt-identity76.5%
associate-*r*76.5%
*-commutative76.5%
*-commutative76.5%
associate-*r*76.5%
Simplified76.5%
Final simplification90.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (sin (* 2.0 (* PI u2)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(u1) * sinf((2.0f * (((float) M_PI) * u2)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(u1) * sin(Float32(Float32(2.0) * Float32(Float32(pi) * u2)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(u1) * sin((single(2.0) * (single(pi) * u2))); end
\begin{array}{l}
\\
\sqrt{u1} \cdot \sin \left(2 \cdot \left(\pi \cdot u2\right)\right)
\end{array}
Initial program 57.2%
sub-neg57.2%
log1p-define98.4%
Simplified98.4%
Taylor expanded in u1 around 0 -0.0%
associate-*r*-0.0%
unpow2-0.0%
rem-square-sqrt4.0%
*-commutative4.0%
associate-*l*4.0%
*-commutative4.0%
mul-1-neg4.0%
Simplified4.0%
expm1-log1p-u4.0%
expm1-undefine5.1%
*-commutative5.1%
add-sqr-sqrt-0.0%
sqrt-unprod33.5%
sqr-neg33.5%
add-sqr-sqrt33.5%
*-commutative33.5%
associate-*r*33.5%
*-commutative33.5%
associate-*l*33.5%
Applied egg-rr33.5%
log1p-undefine33.5%
rem-exp-log33.5%
+-commutative33.5%
associate--l+76.3%
*-commutative76.3%
*-commutative76.3%
associate-*r*76.3%
metadata-eval76.3%
mul0-lft76.3%
distribute-rgt-in76.3%
+-rgt-identity76.3%
associate-*r*76.3%
*-commutative76.3%
*-commutative76.3%
associate-*r*76.3%
Simplified76.3%
Final simplification76.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* (* PI u2) (sqrt u1))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * ((((float) M_PI) * u2) * sqrtf(u1));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(Float32(Float32(pi) * u2) * sqrt(u1))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * ((single(pi) * u2) * sqrt(u1)); end
\begin{array}{l}
\\
2 \cdot \left(\left(\pi \cdot u2\right) \cdot \sqrt{u1}\right)
\end{array}
Initial program 57.2%
sub-neg57.2%
log1p-define98.4%
Simplified98.4%
Taylor expanded in u1 around 0 -0.0%
associate-*r*-0.0%
unpow2-0.0%
rem-square-sqrt4.0%
*-commutative4.0%
associate-*l*4.0%
*-commutative4.0%
mul-1-neg4.0%
Simplified4.0%
add-sqr-sqrt-0.0%
sqrt-unprod76.3%
sqr-neg76.3%
add-sqr-sqrt76.3%
*-commutative76.3%
add-exp-log73.2%
*-commutative73.2%
associate-*r*73.2%
*-commutative73.2%
associate-*l*73.2%
Applied egg-rr73.2%
Taylor expanded in u2 around 0 65.0%
Final simplification65.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (* (* PI u2) (sqrt u1)) -2.0))
float code(float cosTheta_i, float u1, float u2) {
return ((((float) M_PI) * u2) * sqrtf(u1)) * -2.0f;
}
function code(cosTheta_i, u1, u2) return Float32(Float32(Float32(Float32(pi) * u2) * sqrt(u1)) * Float32(-2.0)) end
function tmp = code(cosTheta_i, u1, u2) tmp = ((single(pi) * u2) * sqrt(u1)) * single(-2.0); end
\begin{array}{l}
\\
\left(\left(\pi \cdot u2\right) \cdot \sqrt{u1}\right) \cdot -2
\end{array}
Initial program 57.2%
sub-neg57.2%
log1p-define98.4%
Simplified98.4%
Taylor expanded in u1 around 0 -0.0%
associate-*r*-0.0%
unpow2-0.0%
rem-square-sqrt4.0%
*-commutative4.0%
associate-*l*4.0%
*-commutative4.0%
mul-1-neg4.0%
Simplified4.0%
Taylor expanded in u2 around 0 4.4%
Final simplification4.4%
herbie shell --seed 2024083
(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))))