
(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 8 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 55.1%
sub-neg55.1%
log1p-define98.5%
Simplified98.5%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* (* 2.0 PI) u2)) (sqrt (* u1 (+ 1.0 (* u1 (+ 0.5 (* u1 (+ 0.3333333333333333 (* u1 0.25))))))))))
float code(float cosTheta_i, float u1, float u2) {
return sinf(((2.0f * ((float) M_PI)) * u2)) * sqrtf((u1 * (1.0f + (u1 * (0.5f + (u1 * (0.3333333333333333f + (u1 * 0.25f))))))));
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(Float32(0.5) + Float32(u1 * Float32(Float32(0.3333333333333333) + Float32(u1 * Float32(0.25)))))))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sin(((single(2.0) * single(pi)) * u2)) * sqrt((u1 * (single(1.0) + (u1 * (single(0.5) + (u1 * (single(0.3333333333333333) + (u1 * single(0.25))))))))); end
\begin{array}{l}
\\
\sin \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 + u1 \cdot \left(0.3333333333333333 + u1 \cdot 0.25\right)\right)\right)}
\end{array}
Initial program 55.1%
sub-neg55.1%
log1p-define98.5%
Simplified98.5%
Taylor expanded in u1 around 0 94.3%
*-commutative94.3%
Simplified94.3%
Final simplification94.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* (* 2.0 PI) u2)) (sqrt (* u1 (+ 1.0 (* u1 (+ 0.5 (* u1 0.3333333333333333))))))))
float code(float cosTheta_i, float u1, float u2) {
return sinf(((2.0f * ((float) M_PI)) * u2)) * sqrtf((u1 * (1.0f + (u1 * (0.5f + (u1 * 0.3333333333333333f))))));
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(Float32(0.5) + Float32(u1 * Float32(0.3333333333333333)))))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sin(((single(2.0) * single(pi)) * u2)) * sqrt((u1 * (single(1.0) + (u1 * (single(0.5) + (u1 * single(0.3333333333333333))))))); end
\begin{array}{l}
\\
\sin \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 + u1 \cdot 0.3333333333333333\right)\right)}
\end{array}
Initial program 55.1%
sub-neg55.1%
log1p-define98.5%
Simplified98.5%
Taylor expanded in u1 around 0 92.8%
*-commutative92.8%
Simplified92.8%
Final simplification92.8%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* (* 2.0 PI) u2)))
(if (<= t_0 0.020500000566244125)
(*
2.0
(*
(sqrt (* u1 (+ 1.0 (* u1 (+ 0.5 (* u1 0.3333333333333333))))))
(* PI 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 <= 0.020500000566244125f) {
tmp = 2.0f * (sqrtf((u1 * (1.0f + (u1 * (0.5f + (u1 * 0.3333333333333333f)))))) * (((float) M_PI) * 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(0.020500000566244125)) tmp = Float32(Float32(2.0) * Float32(sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(Float32(0.5) + Float32(u1 * Float32(0.3333333333333333))))))) * Float32(Float32(pi) * u2))); else tmp = Float32(sin(t_0) * sqrt(u1)); end return tmp end
function tmp_2 = code(cosTheta_i, u1, u2) t_0 = (single(2.0) * single(pi)) * u2; tmp = single(0.0); if (t_0 <= single(0.020500000566244125)) tmp = single(2.0) * (sqrt((u1 * (single(1.0) + (u1 * (single(0.5) + (u1 * single(0.3333333333333333))))))) * (single(pi) * u2)); else tmp = sin(t_0) * sqrt(u1); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(2 \cdot \pi\right) \cdot u2\\
\mathbf{if}\;t\_0 \leq 0.020500000566244125:\\
\;\;\;\;2 \cdot \left(\sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 + u1 \cdot 0.3333333333333333\right)\right)} \cdot \left(\pi \cdot u2\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t\_0 \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) < 0.0205000006Initial program 52.4%
sub-neg52.4%
log1p-define98.7%
Simplified98.7%
add-log-exp51.6%
associate-*l*51.6%
Applied egg-rr51.6%
Taylor expanded in u1 around 0 50.7%
*-commutative93.6%
Simplified50.7%
Taylor expanded in u2 around 0 90.6%
if 0.0205000006 < (*.f32 (*.f32 #s(literal 2 binary32) (PI.f32)) u2) Initial program 62.0%
sub-neg62.0%
log1p-define98.1%
Simplified98.1%
Taylor expanded in u1 around 0 75.5%
Final simplification86.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* (* 2.0 PI) u2)) (sqrt (* u1 (+ 1.0 (* u1 0.5))))))
float code(float cosTheta_i, float u1, float u2) {
return sinf(((2.0f * ((float) M_PI)) * u2)) * sqrtf((u1 * (1.0f + (u1 * 0.5f))));
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(Float32(Float32(2.0) * Float32(pi)) * u2)) * sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(0.5)))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sin(((single(2.0) * single(pi)) * u2)) * sqrt((u1 * (single(1.0) + (u1 * single(0.5))))); end
\begin{array}{l}
\\
\sin \left(\left(2 \cdot \pi\right) \cdot u2\right) \cdot \sqrt{u1 \cdot \left(1 + u1 \cdot 0.5\right)}
\end{array}
Initial program 55.1%
sub-neg55.1%
log1p-define98.5%
Simplified98.5%
Taylor expanded in u1 around 0 89.3%
*-commutative89.3%
Simplified89.3%
Final simplification89.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* (sqrt (* u1 (+ 1.0 (* u1 (+ 0.5 (* u1 0.3333333333333333)))))) (* PI u2))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * (sqrtf((u1 * (1.0f + (u1 * (0.5f + (u1 * 0.3333333333333333f)))))) * (((float) M_PI) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(sqrt(Float32(u1 * Float32(Float32(1.0) + Float32(u1 * Float32(Float32(0.5) + Float32(u1 * Float32(0.3333333333333333))))))) * Float32(Float32(pi) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * (sqrt((u1 * (single(1.0) + (u1 * (single(0.5) + (u1 * single(0.3333333333333333))))))) * (single(pi) * u2)); end
\begin{array}{l}
\\
2 \cdot \left(\sqrt{u1 \cdot \left(1 + u1 \cdot \left(0.5 + u1 \cdot 0.3333333333333333\right)\right)} \cdot \left(\pi \cdot u2\right)\right)
\end{array}
Initial program 55.1%
sub-neg55.1%
log1p-define98.5%
Simplified98.5%
add-log-exp63.8%
associate-*l*63.8%
Applied egg-rr63.8%
Taylor expanded in u1 around 0 61.2%
*-commutative92.8%
Simplified61.2%
Taylor expanded in u2 around 0 76.1%
Final simplification76.1%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (* PI u2) (* 2.0 (sqrt u1))))
float code(float cosTheta_i, float u1, float u2) {
return (((float) M_PI) * u2) * (2.0f * sqrtf(u1));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(Float32(pi) * u2) * Float32(Float32(2.0) * sqrt(u1))) end
function tmp = code(cosTheta_i, u1, u2) tmp = (single(pi) * u2) * (single(2.0) * sqrt(u1)); end
\begin{array}{l}
\\
\left(\pi \cdot u2\right) \cdot \left(2 \cdot \sqrt{u1}\right)
\end{array}
Initial program 55.1%
sub-neg55.1%
log1p-define98.5%
Simplified98.5%
Taylor expanded in u1 around 0 78.4%
Taylor expanded in u2 around 0 67.1%
associate-*r*67.1%
Simplified67.1%
Final simplification67.1%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* PI (* u2 (* 2.0 (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
return ((float) M_PI) * (u2 * (2.0f * sqrtf(u1)));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(pi) * Float32(u2 * Float32(Float32(2.0) * sqrt(u1)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(pi) * (u2 * (single(2.0) * sqrt(u1))); end
\begin{array}{l}
\\
\pi \cdot \left(u2 \cdot \left(2 \cdot \sqrt{u1}\right)\right)
\end{array}
Initial program 55.1%
sub-neg55.1%
log1p-define98.5%
Simplified98.5%
Taylor expanded in u1 around 0 78.4%
Taylor expanded in u2 around 0 67.1%
associate-*r*67.1%
Simplified67.1%
pow167.1%
*-commutative67.1%
*-commutative67.1%
associate-*l*67.1%
Applied egg-rr67.1%
unpow167.1%
*-commutative67.1%
Simplified67.1%
Final simplification67.1%
herbie shell --seed 2024110
(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))))