
(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 (* 2.0 (cbrt (* (pow PI 3.0) (pow u2 3.0)))))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((2.0f * cbrtf((powf(((float) M_PI), 3.0f) * powf(u2, 3.0f)))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(Float32(2.0) * cbrt(Float32((Float32(pi) ^ Float32(3.0)) * (u2 ^ Float32(3.0))))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(2 \cdot \sqrt[3]{{\pi}^{3} \cdot {u2}^{3}}\right)
\end{array}
Initial program 57.8%
sub-neg57.8%
log1p-def98.1%
associate-*l*98.1%
Simplified98.1%
add-cbrt-cube98.1%
add-cbrt-cube98.1%
cbrt-unprod98.2%
pow398.2%
pow398.1%
Applied egg-rr98.1%
Final simplification98.1%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.008999999612569809)
(* (sqrt (- (log1p (- u1)))) (* 2.0 (* PI u2)))
(* (sqrt (- u1 (* u1 (* u1 -0.5)))) (sin t_0)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (2.0f * ((float) M_PI));
float tmp;
if (t_0 <= 0.008999999612569809f) {
tmp = sqrtf(-log1pf(-u1)) * (2.0f * (((float) M_PI) * u2));
} else {
tmp = sqrtf((u1 - (u1 * (u1 * -0.5f)))) * sinf(t_0);
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(u2 * Float32(Float32(2.0) * Float32(pi))) tmp = Float32(0.0) if (t_0 <= Float32(0.008999999612569809)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(2.0) * Float32(Float32(pi) * u2))); else tmp = Float32(sqrt(Float32(u1 - Float32(u1 * Float32(u1 * Float32(-0.5))))) * sin(t_0)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(2 \cdot \pi\right)\\
\mathbf{if}\;t_0 \leq 0.008999999612569809:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(2 \cdot \left(\pi \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1 - u1 \cdot \left(u1 \cdot -0.5\right)} \cdot \sin t_0\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.00899999961Initial program 57.8%
sub-neg57.8%
log1p-def98.4%
associate-*l*98.4%
Simplified98.4%
add-cbrt-cube98.4%
add-cbrt-cube98.4%
cbrt-unprod98.5%
pow398.5%
pow398.4%
Applied egg-rr98.4%
Taylor expanded in u2 around 0 96.8%
if 0.00899999961 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 57.9%
Taylor expanded in u1 around 0 88.8%
+-commutative88.8%
mul-1-neg88.8%
unsub-neg88.8%
*-commutative88.8%
unpow288.8%
associate-*l*88.8%
Simplified88.8%
Final simplification94.3%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* 2.0 (* PI u2))))
(if (<= (* u2 (* 2.0 PI)) 0.008999999612569809)
(* (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 ((u2 * (2.0f * ((float) M_PI))) <= 0.008999999612569809f) {
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(u2 * Float32(Float32(2.0) * Float32(pi))) <= Float32(0.008999999612569809)) 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}\;u2 \cdot \left(2 \cdot \pi\right) \leq 0.008999999612569809:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot t_0\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin t_0\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.00899999961Initial program 57.8%
sub-neg57.8%
log1p-def98.4%
associate-*l*98.4%
Simplified98.4%
add-cbrt-cube98.4%
add-cbrt-cube98.4%
cbrt-unprod98.5%
pow398.5%
pow398.4%
Applied egg-rr98.4%
Taylor expanded in u2 around 0 96.8%
if 0.00899999961 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 57.9%
Taylor expanded in u1 around 0 76.1%
mul-1-neg76.1%
Simplified76.1%
Taylor expanded in u2 around inf 76.1%
Final simplification90.6%
(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(2.0) * Float32(Float32(pi) * u2)))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(2 \cdot \left(\pi \cdot u2\right)\right)
\end{array}
Initial program 57.8%
sub-neg57.8%
log1p-def98.1%
associate-*l*98.1%
Simplified98.1%
Final simplification98.1%
(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 57.8%
Taylor expanded in u1 around 0 75.6%
mul-1-neg75.6%
Simplified75.6%
Taylor expanded in u2 around inf 75.6%
Final simplification75.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* u2 (* PI (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * (u2 * (((float) M_PI) * sqrtf(u1)));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(u2 * Float32(Float32(pi) * sqrt(u1)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * (u2 * (single(pi) * sqrt(u1))); end
\begin{array}{l}
\\
2 \cdot \left(u2 \cdot \left(\pi \cdot \sqrt{u1}\right)\right)
\end{array}
Initial program 57.8%
flip--55.6%
clear-num55.4%
log-div55.5%
metadata-eval55.5%
metadata-eval55.5%
sub-neg55.5%
add-sqr-sqrt55.5%
sqrt-unprod55.5%
sqr-neg55.5%
sqrt-unprod-0.0%
add-sqr-sqrt38.1%
distribute-lft-neg-out38.1%
sqr-neg38.1%
Applied egg-rr38.1%
log-div38.1%
log1p-def72.2%
unpow272.2%
log1p-def71.2%
unpow271.2%
associate--r-71.2%
neg-sub071.2%
+-commutative71.2%
sub-neg71.2%
Simplified71.2%
Taylor expanded in u2 around 0 34.7%
associate-*l*34.7%
log1p-def62.3%
log1p-def61.7%
unpow261.7%
Simplified61.7%
Taylor expanded in u1 around 0 64.9%
Final simplification64.9%
herbie shell --seed 2023279
(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))))