
(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 5 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 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 61.6%
sub-neg61.6%
log1p-def98.5%
Simplified98.5%
Final simplification98.5%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* (* 2.0 PI) u2)))
(if (<= t_0 0.0012499999720603228)
(* (sqrt (- (log1p (- u1)))) (* PI (* 2.0 u2)))
(* (sin t_0) (sqrt (* u1 (- (* u1 (- -0.5)) -1.0)))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = (2.0f * ((float) M_PI)) * u2;
float tmp;
if (t_0 <= 0.0012499999720603228f) {
tmp = sqrtf(-log1pf(-u1)) * (((float) M_PI) * (2.0f * u2));
} else {
tmp = sinf(t_0) * sqrtf((u1 * ((u1 * -(-0.5f)) - -1.0f)));
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(Float32(Float32(2.0) * Float32(pi)) * u2) tmp = Float32(0.0) if (t_0 <= Float32(0.0012499999720603228)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(pi) * Float32(Float32(2.0) * u2))); else tmp = Float32(sin(t_0) * sqrt(Float32(u1 * Float32(Float32(u1 * Float32(-Float32(-0.5))) - Float32(-1.0))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(2 \cdot \pi\right) \cdot u2\\
\mathbf{if}\;t_0 \leq 0.0012499999720603228:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(\pi \cdot \left(2 \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t_0 \cdot \sqrt{u1 \cdot \left(u1 \cdot \left(--0.5\right) - -1\right)}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.00124999997Initial program 60.5%
sub-neg60.5%
log1p-def98.7%
Simplified98.7%
add-cbrt-cube98.7%
add-cbrt-cube98.7%
cbrt-unprod98.6%
pow398.6%
pow398.7%
Applied egg-rr98.7%
Taylor expanded in u2 around 0 98.6%
associate-*r*98.6%
*-commutative98.6%
Simplified98.6%
if 0.00124999997 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 63.7%
Taylor expanded in u1 around 0 88.2%
unpow288.2%
associate-*r*88.2%
distribute-rgt-out88.1%
Simplified88.1%
Final simplification95.0%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* (* 2.0 PI) u2)))
(if (<= t_0 0.010999999940395355)
(* (sqrt (- (log1p (- u1)))) (* PI (* 2.0 u2)))
(* (sin t_0) (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = (2.0f * ((float) M_PI)) * u2;
float tmp;
if (t_0 <= 0.010999999940395355f) {
tmp = sqrtf(-log1pf(-u1)) * (((float) M_PI) * (2.0f * u2));
} else {
tmp = sinf(t_0) * sqrtf(u1);
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(Float32(Float32(2.0) * Float32(pi)) * u2) tmp = Float32(0.0) if (t_0 <= Float32(0.010999999940395355)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(pi) * Float32(Float32(2.0) * u2))); else tmp = Float32(sin(t_0) * sqrt(u1)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(2 \cdot \pi\right) \cdot u2\\
\mathbf{if}\;t_0 \leq 0.010999999940395355:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(\pi \cdot \left(2 \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t_0 \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.0109999999Initial program 61.5%
sub-neg61.5%
log1p-def98.7%
Simplified98.7%
add-cbrt-cube98.7%
add-cbrt-cube98.6%
cbrt-unprod98.6%
pow398.6%
pow398.7%
Applied egg-rr98.7%
Taylor expanded in u2 around 0 96.8%
associate-*r*96.8%
*-commutative96.8%
Simplified96.8%
if 0.0109999999 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 61.9%
sub-neg61.9%
log1p-def97.9%
Simplified97.9%
neg-mul-197.9%
log1p-udef61.9%
sub-neg61.9%
neg-mul-161.9%
add-cube-cbrt61.7%
pow361.7%
Applied egg-rr71.9%
Taylor expanded in u1 around 0 74.3%
Final simplification91.1%
(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(Float32(2.0) * 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(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{u1}
\end{array}
Initial program 61.6%
sub-neg61.6%
log1p-def98.5%
Simplified98.5%
neg-mul-198.5%
log1p-udef61.6%
sub-neg61.6%
neg-mul-161.6%
add-cube-cbrt61.5%
pow361.5%
Applied egg-rr71.9%
Taylor expanded in u1 around 0 74.4%
Final simplification74.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* (sqrt u1) (* PI u2))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * (sqrtf(u1) * (((float) M_PI) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(sqrt(u1) * Float32(Float32(pi) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * (sqrt(u1) * (single(pi) * u2)); end
\begin{array}{l}
\\
2 \cdot \left(\sqrt{u1} \cdot \left(\pi \cdot u2\right)\right)
\end{array}
Initial program 61.6%
Taylor expanded in u1 around 0 74.4%
mul-1-neg74.4%
Simplified74.4%
Taylor expanded in u2 around 0 66.4%
Final simplification66.4%
herbie shell --seed 2024026
(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))))