
(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 7 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 (log1p (expm1 (* PI u2)))))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((2.0f * log1pf(expm1f((((float) M_PI) * u2)))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(Float32(2.0) * log1p(expm1(Float32(Float32(pi) * u2)))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(2 \cdot \mathsf{log1p}\left(\mathsf{expm1}\left(\pi \cdot u2\right)\right)\right)
\end{array}
Initial program 58.8%
sub-neg58.8%
log1p-def98.3%
associate-*l*98.3%
Simplified98.3%
log1p-expm1-u98.3%
Applied egg-rr98.3%
Final simplification98.3%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.006000000052154064)
(* (sqrt (- (log1p (- u1)))) (* PI (* 2.0 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 <= 0.006000000052154064f) {
tmp = sqrtf(-log1pf(-u1)) * (((float) M_PI) * (2.0f * 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(0.006000000052154064)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(pi) * Float32(Float32(2.0) * 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 0.006000000052154064:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(\pi \cdot \left(2 \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) < 0.00600000005Initial program 58.6%
sub-neg58.6%
log1p-def98.6%
associate-*l*98.6%
Simplified98.6%
add-cbrt-cube98.6%
add-cbrt-cube98.6%
cbrt-unprod98.5%
pow398.5%
pow398.4%
Applied egg-rr98.4%
Taylor expanded in u2 around 0 97.8%
associate-*r*97.8%
*-commutative97.8%
Simplified97.8%
if 0.00600000005 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 59.2%
Taylor expanded in u1 around 0 85.8%
+-commutative85.8%
mul-1-neg85.8%
unsub-neg85.8%
*-commutative85.8%
unpow285.8%
associate-*l*85.8%
Simplified85.8%
Final simplification94.1%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= (* u2 (* 2.0 PI)) 0.017000000923871994) (* (sqrt (- (log1p (- u1)))) (* PI (* 2.0 u2))) (* (sin (* 2.0 (* PI u2))) (sqrt u1))))
float code(float cosTheta_i, float u1, float u2) {
float tmp;
if ((u2 * (2.0f * ((float) M_PI))) <= 0.017000000923871994f) {
tmp = sqrtf(-log1pf(-u1)) * (((float) M_PI) * (2.0f * u2));
} else {
tmp = sinf((2.0f * (((float) M_PI) * u2))) * sqrtf(u1);
}
return tmp;
}
function code(cosTheta_i, u1, u2) tmp = Float32(0.0) if (Float32(u2 * Float32(Float32(2.0) * Float32(pi))) <= Float32(0.017000000923871994)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(pi) * Float32(Float32(2.0) * u2))); else tmp = Float32(sin(Float32(Float32(2.0) * Float32(Float32(pi) * u2))) * sqrt(u1)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u2 \cdot \left(2 \cdot \pi\right) \leq 0.017000000923871994:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(\pi \cdot \left(2 \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin \left(2 \cdot \left(\pi \cdot u2\right)\right) \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.0170000009Initial program 58.9%
sub-neg58.9%
log1p-def98.6%
associate-*l*98.6%
Simplified98.6%
add-cbrt-cube98.6%
add-cbrt-cube98.6%
cbrt-unprod98.5%
pow398.5%
pow398.5%
Applied egg-rr98.5%
Taylor expanded in u2 around 0 96.9%
associate-*r*96.9%
*-commutative96.9%
Simplified96.9%
if 0.0170000009 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 58.5%
sub-neg58.5%
log1p-def97.6%
associate-*l*97.6%
Simplified97.6%
neg-mul-197.6%
log1p-udef58.5%
sub-neg58.5%
neg-mul-158.5%
add-sqr-sqrt58.5%
pow258.5%
Applied egg-rr73.0%
Taylor expanded in u1 around 0 75.1%
Final simplification90.7%
(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 58.8%
sub-neg58.8%
log1p-def98.3%
associate-*l*98.3%
Simplified98.3%
Final simplification98.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* 2.0 (* PI u2))) (sqrt u1)))
float code(float cosTheta_i, float u1, float u2) {
return sinf((2.0f * (((float) M_PI) * u2))) * sqrtf(u1);
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(Float32(2.0) * Float32(Float32(pi) * u2))) * sqrt(u1)) end
function tmp = code(cosTheta_i, u1, u2) tmp = sin((single(2.0) * (single(pi) * u2))) * sqrt(u1); end
\begin{array}{l}
\\
\sin \left(2 \cdot \left(\pi \cdot u2\right)\right) \cdot \sqrt{u1}
\end{array}
Initial program 58.8%
sub-neg58.8%
log1p-def98.3%
associate-*l*98.3%
Simplified98.3%
neg-mul-198.3%
log1p-udef58.8%
sub-neg58.8%
neg-mul-158.8%
add-sqr-sqrt58.7%
pow258.7%
Applied egg-rr73.5%
Taylor expanded in u1 around 0 75.7%
Final simplification75.7%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* PI (sqrt (* u1 (* u2 u2))))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * (((float) M_PI) * sqrtf((u1 * (u2 * u2))));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(Float32(pi) * sqrt(Float32(u1 * Float32(u2 * u2))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * (single(pi) * sqrt((u1 * (u2 * u2)))); end
\begin{array}{l}
\\
2 \cdot \left(\pi \cdot \sqrt{u1 \cdot \left(u2 \cdot u2\right)}\right)
\end{array}
Initial program 58.8%
Taylor expanded in u1 around 0 75.7%
mul-1-neg75.7%
Simplified75.7%
Taylor expanded in u2 around 0 65.4%
associate-*r*65.4%
Simplified65.4%
Taylor expanded in u2 around 0 65.4%
associate-*r*65.5%
Simplified65.5%
add-sqr-sqrt65.3%
sqrt-unprod65.5%
swap-sqr65.5%
add-sqr-sqrt65.5%
Applied egg-rr65.5%
Final simplification65.5%
(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(pi) * Float32(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(\pi \cdot \left(u2 \cdot \sqrt{u1}\right)\right)
\end{array}
Initial program 58.8%
Taylor expanded in u1 around 0 75.7%
mul-1-neg75.7%
Simplified75.7%
Taylor expanded in u2 around 0 65.4%
associate-*r*65.4%
Simplified65.4%
Taylor expanded in u2 around 0 65.4%
associate-*r*65.5%
Simplified65.5%
Final simplification65.5%
herbie shell --seed 2023285
(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))))