
(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 (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 58.9%
sub-neg58.9%
log1p-def98.2%
Simplified98.2%
add-cbrt-cube98.2%
add-cbrt-cube98.1%
cbrt-unprod98.2%
pow398.2%
pow398.2%
Applied egg-rr98.2%
Final simplification98.2%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* 2.0 (* PI u2))))
(if (<= (* (* 2.0 PI) u2) 0.014999999664723873)
(* (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) <= 0.014999999664723873f) {
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(0.014999999664723873)) 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 0.014999999664723873:\\
\;\;\;\;\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) < 0.0149999997Initial program 59.7%
sub-neg59.7%
log1p-def98.3%
Simplified98.3%
add-cbrt-cube98.3%
add-cbrt-cube98.2%
cbrt-unprod98.3%
pow398.3%
pow398.3%
Applied egg-rr98.3%
Taylor expanded in u2 around 0 95.5%
if 0.0149999997 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 56.5%
Taylor expanded in u1 around 0 79.2%
mul-1-neg79.2%
Simplified79.2%
Taylor expanded in u2 around inf 79.2%
Final simplification91.7%
(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(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 58.9%
sub-neg58.9%
log1p-def98.2%
Simplified98.2%
Final simplification98.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= u1 0.0024999999441206455) (* (sin (* (* 2.0 PI) u2)) (sqrt (* u1 (- (- -1.0) (* u1 -0.5))))) (* (sqrt (- (log1p (- u1)))) (* 2.0 (* PI u2)))))
float code(float cosTheta_i, float u1, float u2) {
float tmp;
if (u1 <= 0.0024999999441206455f) {
tmp = sinf(((2.0f * ((float) M_PI)) * u2)) * sqrtf((u1 * (-(-1.0f) - (u1 * -0.5f))));
} else {
tmp = sqrtf(-log1pf(-u1)) * (2.0f * (((float) M_PI) * u2));
}
return tmp;
}
function code(cosTheta_i, u1, u2) tmp = Float32(0.0) if (u1 <= Float32(0.0024999999441206455)) tmp = Float32(sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(Float32(u1 * Float32(Float32(-Float32(-1.0)) - Float32(u1 * Float32(-0.5)))))); else tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(2.0) * Float32(Float32(pi) * u2))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u1 \leq 0.0024999999441206455:\\
\;\;\;\;\sin \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{u1 \cdot \left(\left(--1\right) - u1 \cdot -0.5\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(2 \cdot \left(\pi \cdot u2\right)\right)\\
\end{array}
\end{array}
if u1 < 0.00249999994Initial program 46.4%
Taylor expanded in u1 around 0 97.9%
*-commutative97.9%
*-commutative97.9%
unpow297.9%
associate-*l*97.9%
distribute-lft-out97.8%
Simplified97.8%
if 0.00249999994 < u1 Initial program 94.2%
sub-neg94.2%
log1p-def98.2%
Simplified98.2%
add-cbrt-cube98.2%
add-cbrt-cube98.1%
cbrt-unprod98.1%
pow398.1%
pow398.1%
Applied egg-rr98.1%
Taylor expanded in u2 around 0 87.9%
Final simplification95.2%
(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 58.9%
Taylor expanded in u1 around 0 76.7%
mul-1-neg76.7%
Simplified76.7%
Taylor expanded in u2 around inf 76.7%
Final simplification76.7%
(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 58.9%
Taylor expanded in u1 around 0 76.7%
mul-1-neg76.7%
Simplified76.7%
add-cube-cbrt76.3%
pow376.5%
*-commutative76.5%
associate-*r*76.5%
Applied egg-rr76.5%
Taylor expanded in u2 around 0 67.6%
*-commutative67.6%
associate-*r*67.7%
Simplified67.7%
Final simplification67.7%
(FPCore (cosTheta_i u1 u2) :precision binary32 0.0)
float code(float cosTheta_i, float u1, float u2) {
return 0.0f;
}
real(4) function code(costheta_i, u1, u2)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: u1
real(4), intent (in) :: u2
code = 0.0e0
end function
function code(cosTheta_i, u1, u2) return Float32(0.0) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(0.0); end
\begin{array}{l}
\\
0
\end{array}
Initial program 58.9%
add-cube-cbrt58.8%
pow358.8%
*-commutative58.8%
associate-*r*58.8%
Applied egg-rr58.8%
Taylor expanded in u2 around 0 7.2%
Final simplification7.2%
herbie shell --seed 2023319
(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))))