
(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 (* 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 56.1%
sub-neg56.1%
log1p-def98.4%
associate-*l*98.4%
Simplified98.4%
Final simplification98.4%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.0013000000035390258)
(* (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 <= 0.0013000000035390258f) {
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(0.0013000000035390258)) 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 0.0013000000035390258:\\
\;\;\;\;\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) < 0.0013Initial program 55.2%
sub-neg55.2%
log1p-def98.6%
associate-*l*98.6%
Simplified98.6%
add-sqr-sqrt97.7%
pow297.7%
Applied egg-rr97.7%
Taylor expanded in u2 around 0 98.5%
if 0.0013 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 57.5%
Taylor expanded in u1 around 0 89.0%
+-commutative89.0%
mul-1-neg89.0%
unsub-neg89.0%
unpow289.0%
associate-*r*89.0%
Simplified89.0%
Final simplification94.7%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* 2.0 (* PI u2))))
(if (<= (* u2 (* 2.0 PI)) 0.0044999998062849045)
(* (sqrt (- (log1p (- u1)))) t_0)
(* (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 ((u2 * (2.0f * ((float) M_PI))) <= 0.0044999998062849045f) {
tmp = sqrtf(-log1pf(-u1)) * t_0;
} else {
tmp = sinf(t_0) * sqrtf(u1);
}
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(0.0044999998062849045)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * t_0); else tmp = Float32(sin(t_0) * sqrt(u1)); 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 0.0044999998062849045:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot t_0\\
\mathbf{else}:\\
\;\;\;\;\sin t_0 \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.00449999981Initial program 54.9%
sub-neg54.9%
log1p-def98.6%
associate-*l*98.6%
Simplified98.6%
add-sqr-sqrt97.6%
pow297.6%
Applied egg-rr97.6%
Taylor expanded in u2 around 0 97.3%
if 0.00449999981 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 58.7%
sub-neg58.7%
log1p-def98.1%
associate-*l*98.1%
Simplified98.1%
log1p-udef58.7%
sub-neg58.7%
add-sqr-sqrt58.6%
pow258.6%
Applied egg-rr73.7%
Taylor expanded in u1 around 0 76.0%
Final simplification90.5%
(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 56.1%
sub-neg56.1%
log1p-def98.4%
associate-*l*98.4%
Simplified98.4%
log1p-udef56.1%
sub-neg56.1%
add-sqr-sqrt56.1%
pow256.1%
Applied egg-rr76.0%
Taylor expanded in u1 around 0 78.2%
Final simplification78.2%
(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(Float32(2.0) * 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}
\\
\left(2 \cdot u2\right) \cdot \left(\pi \cdot \sqrt{u1}\right)
\end{array}
Initial program 56.1%
Taylor expanded in u1 around 0 78.2%
mul-1-neg78.2%
Simplified78.2%
add-exp-log73.9%
associate-*r*73.9%
remove-double-neg73.9%
Applied egg-rr73.9%
add-exp-log78.2%
associate-*r*78.2%
*-commutative78.2%
*-commutative78.2%
Applied egg-rr78.2%
Taylor expanded in u2 around 0 69.6%
associate-*l*69.5%
associate-*r*69.5%
Simplified69.5%
Final simplification69.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (* PI (* 2.0 u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(u1) * (((float) M_PI) * (2.0f * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(u1) * Float32(Float32(pi) * Float32(Float32(2.0) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(u1) * (single(pi) * (single(2.0) * u2)); end
\begin{array}{l}
\\
\sqrt{u1} \cdot \left(\pi \cdot \left(2 \cdot u2\right)\right)
\end{array}
Initial program 56.1%
Taylor expanded in u1 around 0 78.2%
mul-1-neg78.2%
Simplified78.2%
Taylor expanded in u2 around 0 69.6%
associate-*r*69.6%
associate-*r*69.6%
Simplified69.6%
Final simplification69.6%
herbie shell --seed 2023258
(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))))