
(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 (* (cbrt (* (* PI PI) 4.0)) (* (cbrt (* PI 2.0)) u2)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((cbrtf(((((float) M_PI) * ((float) M_PI)) * 4.0f)) * (cbrtf((((float) M_PI) * 2.0f)) * u2)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(cbrt(Float32(Float32(Float32(pi) * Float32(pi)) * Float32(4.0))) * Float32(cbrt(Float32(Float32(pi) * Float32(2.0))) * u2)))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(\sqrt[3]{\left(\pi \cdot \pi\right) \cdot 4} \cdot \left(\sqrt[3]{\pi \cdot 2} \cdot u2\right)\right)
\end{array}
Initial program 58.9%
sub-neg58.9%
log1p-def98.3%
Simplified98.3%
expm1-log1p-u98.2%
associate-*l*98.2%
Applied egg-rr98.2%
expm1-log1p-u98.3%
associate-*r*98.3%
add-cube-cbrt98.3%
associate-*l*98.5%
cbrt-unprod98.5%
*-commutative98.5%
*-commutative98.5%
swap-sqr98.5%
pow298.5%
metadata-eval98.5%
*-commutative98.5%
Applied egg-rr98.5%
unpow298.5%
Applied egg-rr98.5%
Final simplification98.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (* 2.0 (* (sin (* PI u2)) (cos (* PI u2))))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * (2.0f * (sinf((((float) M_PI) * u2)) * cosf((((float) M_PI) * u2))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(2.0) * Float32(sin(Float32(Float32(pi) * u2)) * cos(Float32(Float32(pi) * u2))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(2 \cdot \left(\sin \left(\pi \cdot u2\right) \cdot \cos \left(\pi \cdot u2\right)\right)\right)
\end{array}
Initial program 58.9%
sub-neg58.9%
log1p-def98.3%
Simplified98.3%
associate-*l*98.3%
sin-298.3%
Applied egg-rr98.3%
Final simplification98.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (sin (* u2 (* PI 2.0)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((u2 * (((float) M_PI) * 2.0f)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(u2 * Float32(Float32(pi) * Float32(2.0))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(u2 \cdot \left(\pi \cdot 2\right)\right)
\end{array}
Initial program 58.9%
sub-neg58.9%
log1p-def98.3%
Simplified98.3%
Final simplification98.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* u2 (* PI 2.0))) (sqrt (* u1 (- (- -1.0) (* u1 -0.5))))))
float code(float cosTheta_i, float u1, float u2) {
return sinf((u2 * (((float) M_PI) * 2.0f))) * sqrtf((u1 * (-(-1.0f) - (u1 * -0.5f))));
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(u2 * Float32(Float32(pi) * Float32(2.0)))) * sqrt(Float32(u1 * Float32(Float32(-Float32(-1.0)) - Float32(u1 * Float32(-0.5)))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sin((u2 * (single(pi) * single(2.0)))) * sqrt((u1 * (-single(-1.0) - (u1 * single(-0.5))))); end
\begin{array}{l}
\\
\sin \left(u2 \cdot \left(\pi \cdot 2\right)\right) \cdot \sqrt{u1 \cdot \left(\left(--1\right) - u1 \cdot -0.5\right)}
\end{array}
Initial program 58.9%
Taylor expanded in u1 around 0 87.0%
unpow287.0%
associate-*r*87.0%
distribute-rgt-out86.9%
Simplified86.9%
Final simplification86.9%
(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 75.2%
mul-1-neg75.2%
Simplified75.2%
Taylor expanded in u2 around inf 75.2%
Final simplification75.2%
(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 58.9%
Taylor expanded in u1 around 0 75.2%
mul-1-neg75.2%
Simplified75.2%
Taylor expanded in u2 around 0 64.4%
Final simplification64.4%
herbie shell --seed 2024031
(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))))