
(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 (* 2.0 (log1p (expm1 (* PI u2)))))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((2.0f * log1pf(expm1f((((float) M_PI) * u2)))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(Float32(2.0) * log1p(expm1(Float32(Float32(pi) * u2)))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(2 \cdot \mathsf{log1p}\left(\mathsf{expm1}\left(\pi \cdot u2\right)\right)\right)
\end{array}
Initial program 56.9%
sub-neg56.9%
log1p-def98.3%
associate-*l*98.3%
Simplified98.3%
log1p-expm1-u98.3%
Applied egg-rr98.3%
Final simplification98.3%
(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 56.9%
sub-neg56.9%
log1p-def98.3%
associate-*l*98.3%
Simplified98.3%
Final simplification98.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= (- 1.0 u1) 0.9900000095367432) (* (sqrt (- (log (- 1.0 u1)))) (* 2.0 (* PI u2))) (* (sqrt (- u1 (* u1 (* u1 -0.5)))) (sin (* u2 (* 2.0 PI))))))
float code(float cosTheta_i, float u1, float u2) {
float tmp;
if ((1.0f - u1) <= 0.9900000095367432f) {
tmp = sqrtf(-logf((1.0f - u1))) * (2.0f * (((float) M_PI) * u2));
} else {
tmp = sqrtf((u1 - (u1 * (u1 * -0.5f)))) * sinf((u2 * (2.0f * ((float) M_PI))));
}
return tmp;
}
function code(cosTheta_i, u1, u2) tmp = Float32(0.0) if (Float32(Float32(1.0) - u1) <= Float32(0.9900000095367432)) tmp = Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * Float32(Float32(2.0) * Float32(Float32(pi) * u2))); else tmp = Float32(sqrt(Float32(u1 - Float32(u1 * Float32(u1 * Float32(-0.5))))) * sin(Float32(u2 * Float32(Float32(2.0) * Float32(pi))))); end return tmp end
function tmp_2 = code(cosTheta_i, u1, u2) tmp = single(0.0); if ((single(1.0) - u1) <= single(0.9900000095367432)) tmp = sqrt(-log((single(1.0) - u1))) * (single(2.0) * (single(pi) * u2)); else tmp = sqrt((u1 - (u1 * (u1 * single(-0.5))))) * sin((u2 * (single(2.0) * single(pi)))); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u1 \leq 0.9900000095367432:\\
\;\;\;\;\sqrt{-\log \left(1 - 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 \left(u2 \cdot \left(2 \cdot \pi\right)\right)\\
\end{array}
\end{array}
if (-.f32 1 u1) < 0.99000001Initial program 96.7%
associate-*r*96.7%
add-exp-log92.5%
Applied egg-rr92.5%
Taylor expanded in u2 around 0 77.7%
if 0.99000001 < (-.f32 1 u1) Initial program 47.5%
Taylor expanded in u1 around 0 96.7%
+-commutative96.7%
mul-1-neg96.7%
unsub-neg96.7%
*-commutative96.7%
unpow296.7%
associate-*l*96.7%
Simplified96.7%
Final simplification93.1%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* 2.0 (* PI u2))))
(if (<= (- 1.0 u1) 0.9990000128746033)
(* (sqrt (- (log (- 1.0 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 ((1.0f - u1) <= 0.9990000128746033f) {
tmp = sqrtf(-logf((1.0f - 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(1.0) - u1) <= Float32(0.9990000128746033)) tmp = Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * t_0); else tmp = Float32(sqrt(u1) * sin(t_0)); 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 ((single(1.0) - u1) <= single(0.9990000128746033)) tmp = sqrt(-log((single(1.0) - u1))) * t_0; else tmp = sqrt(u1) * sin(t_0); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 2 \cdot \left(\pi \cdot u2\right)\\
\mathbf{if}\;1 - u1 \leq 0.9990000128746033:\\
\;\;\;\;\sqrt{-\log \left(1 - u1\right)} \cdot t_0\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1} \cdot \sin t_0\\
\end{array}
\end{array}
if (-.f32 1 u1) < 0.999000013Initial program 92.7%
associate-*r*92.7%
add-exp-log90.1%
Applied egg-rr90.1%
Taylor expanded in u2 around 0 75.3%
if 0.999000013 < (-.f32 1 u1) Initial program 41.8%
Taylor expanded in u1 around 0 88.9%
mul-1-neg88.9%
Simplified88.9%
Taylor expanded in u2 around inf 88.9%
Final simplification84.9%
(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 56.9%
Taylor expanded in u1 around 0 76.4%
mul-1-neg76.4%
Simplified76.4%
Taylor expanded in u2 around inf 76.4%
Final simplification76.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* PI (* 2.0 (sqrt (* u2 (* u1 u2))))))
float code(float cosTheta_i, float u1, float u2) {
return ((float) M_PI) * (2.0f * sqrtf((u2 * (u1 * u2))));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(pi) * Float32(Float32(2.0) * sqrt(Float32(u2 * Float32(u1 * u2))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(pi) * (single(2.0) * sqrt((u2 * (u1 * u2)))); end
\begin{array}{l}
\\
\pi \cdot \left(2 \cdot \sqrt{u2 \cdot \left(u1 \cdot u2\right)}\right)
\end{array}
Initial program 56.9%
Taylor expanded in u1 around 0 76.4%
mul-1-neg76.4%
Simplified76.4%
Taylor expanded in u2 around 0 65.5%
associate-*r*65.5%
*-commutative65.5%
Simplified65.5%
Taylor expanded in u2 around 0 65.5%
*-commutative65.5%
*-commutative65.5%
*-commutative65.5%
associate-*l*65.6%
associate-*l*65.6%
Simplified65.6%
add-sqr-sqrt65.4%
sqrt-unprod65.6%
*-commutative65.6%
*-commutative65.6%
swap-sqr65.5%
add-sqr-sqrt65.6%
Applied egg-rr65.6%
*-commutative65.6%
associate-*l*65.6%
Simplified65.6%
Final simplification65.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* PI (* 2.0 (* u2 (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
return ((float) M_PI) * (2.0f * (u2 * sqrtf(u1)));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(pi) * Float32(Float32(2.0) * Float32(u2 * sqrt(u1)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(pi) * (single(2.0) * (u2 * sqrt(u1))); end
\begin{array}{l}
\\
\pi \cdot \left(2 \cdot \left(u2 \cdot \sqrt{u1}\right)\right)
\end{array}
Initial program 56.9%
Taylor expanded in u1 around 0 76.4%
mul-1-neg76.4%
Simplified76.4%
Taylor expanded in u2 around 0 65.5%
associate-*r*65.5%
*-commutative65.5%
Simplified65.5%
Taylor expanded in u2 around 0 65.5%
*-commutative65.5%
*-commutative65.5%
*-commutative65.5%
associate-*l*65.6%
associate-*l*65.6%
Simplified65.6%
Final simplification65.6%
herbie shell --seed 2023283
(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))))