
(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 (let* ((t_0 (sqrt (* 2.0 PI)))) (* (sqrt (- (log1p (- u1)))) (sin (* t_0 (* u2 t_0))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = sqrtf((2.0f * ((float) M_PI)));
return sqrtf(-log1pf(-u1)) * sinf((t_0 * (u2 * t_0)));
}
function code(cosTheta_i, u1, u2) t_0 = sqrt(Float32(Float32(2.0) * Float32(pi))) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(t_0 * Float32(u2 * t_0)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{2 \cdot \pi}\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(t_0 \cdot \left(u2 \cdot t_0\right)\right)
\end{array}
\end{array}
Initial program 57.8%
sub-neg57.8%
log1p-def98.3%
Simplified98.3%
expm1-log1p-u98.2%
associate-*l*98.2%
Applied egg-rr98.2%
expm1-log1p-u98.3%
*-commutative98.3%
*-commutative98.3%
associate-*r*98.3%
add-sqr-sqrt98.3%
associate-*r*98.4%
*-commutative98.4%
*-commutative98.4%
Applied egg-rr98.4%
Final simplification98.4%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 8.000000093488779e-7)
(* (sqrt (- (log1p (- u1)))) (log1p t_0))
(* (sin t_0) (sqrt (* u1 (- (- -1.0) (* u1 -0.5))))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (2.0f * ((float) M_PI));
float tmp;
if (t_0 <= 8.000000093488779e-7f) {
tmp = sqrtf(-log1pf(-u1)) * log1pf(t_0);
} else {
tmp = sinf(t_0) * sqrtf((u1 * (-(-1.0f) - (u1 * -0.5f))));
}
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(8.000000093488779e-7)) tmp = Float32(sqrt(Float32(-log1p(Float32(-u1)))) * log1p(t_0)); else tmp = Float32(sin(t_0) * sqrt(Float32(u1 * Float32(Float32(-Float32(-1.0)) - Float32(u1 * Float32(-0.5)))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(2 \cdot \pi\right)\\
\mathbf{if}\;t_0 \leq 8.000000093488779 \cdot 10^{-7}:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \mathsf{log1p}\left(t_0\right)\\
\mathbf{else}:\\
\;\;\;\;\sin t_0 \cdot \sqrt{u1 \cdot \left(\left(--1\right) - u1 \cdot -0.5\right)}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 8.00000009e-7Initial program 59.2%
sub-neg59.2%
log1p-def98.4%
Simplified98.4%
log1p-expm1-u98.4%
associate-*l*98.4%
Applied egg-rr98.4%
Taylor expanded in u2 around 0 97.6%
*-commutative97.6%
*-commutative97.6%
*-commutative97.6%
associate-*l*97.6%
Simplified97.6%
if 8.00000009e-7 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 57.2%
Taylor expanded in u1 around 0 89.8%
unpow289.8%
associate-*r*89.8%
distribute-rgt-out89.7%
Simplified89.7%
Final simplification92.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (sin (* u2 (* 2.0 PI)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * sinf((u2 * (2.0f * ((float) M_PI))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * sin(Float32(u2 * Float32(Float32(2.0) * Float32(pi))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \sin \left(u2 \cdot \left(2 \cdot \pi\right)\right)
\end{array}
Initial program 57.8%
sub-neg57.8%
log1p-def98.3%
Simplified98.3%
Final simplification98.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sin (* u2 (* 2.0 PI))) (sqrt (* u1 (- (- -1.0) (* u1 -0.5))))))
float code(float cosTheta_i, float u1, float u2) {
return sinf((u2 * (2.0f * ((float) M_PI)))) * sqrtf((u1 * (-(-1.0f) - (u1 * -0.5f))));
}
function code(cosTheta_i, u1, u2) return Float32(sin(Float32(u2 * Float32(Float32(2.0) * Float32(pi)))) * 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(2.0) * single(pi)))) * sqrt((u1 * (-single(-1.0) - (u1 * single(-0.5))))); end
\begin{array}{l}
\\
\sin \left(u2 \cdot \left(2 \cdot \pi\right)\right) \cdot \sqrt{u1 \cdot \left(\left(--1\right) - u1 \cdot -0.5\right)}
\end{array}
Initial program 57.8%
Taylor expanded in u1 around 0 89.0%
unpow289.0%
associate-*r*89.0%
distribute-rgt-out88.9%
Simplified88.9%
Final simplification88.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt u1) (sin (* 2.0 (* u2 PI)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(u1) * sinf((2.0f * (u2 * ((float) M_PI))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(u1) * sin(Float32(Float32(2.0) * Float32(u2 * Float32(pi))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(u1) * sin((single(2.0) * (u2 * single(pi)))); end
\begin{array}{l}
\\
\sqrt{u1} \cdot \sin \left(2 \cdot \left(u2 \cdot \pi\right)\right)
\end{array}
Initial program 57.8%
Taylor expanded in u1 around 0 77.0%
mul-1-neg77.0%
Simplified77.0%
Taylor expanded in u2 around inf 77.0%
Final simplification77.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* PI (* u2 (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * (((float) M_PI) * (u2 * sqrtf(u1)));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(Float32(pi) * Float32(u2 * sqrt(u1)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * (single(pi) * (u2 * sqrt(u1))); end
\begin{array}{l}
\\
2 \cdot \left(\pi \cdot \left(u2 \cdot \sqrt{u1}\right)\right)
\end{array}
Initial program 57.8%
Taylor expanded in u1 around 0 77.0%
mul-1-neg77.0%
Simplified77.0%
Taylor expanded in u2 around 0 67.4%
*-commutative67.4%
*-commutative67.4%
associate-*l*67.3%
Simplified67.3%
Final simplification67.3%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* 2.0 (* (sqrt u1) (* u2 PI))))
float code(float cosTheta_i, float u1, float u2) {
return 2.0f * (sqrtf(u1) * (u2 * ((float) M_PI)));
}
function code(cosTheta_i, u1, u2) return Float32(Float32(2.0) * Float32(sqrt(u1) * Float32(u2 * Float32(pi)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = single(2.0) * (sqrt(u1) * (u2 * single(pi))); end
\begin{array}{l}
\\
2 \cdot \left(\sqrt{u1} \cdot \left(u2 \cdot \pi\right)\right)
\end{array}
Initial program 57.8%
Taylor expanded in u1 around 0 77.0%
mul-1-neg77.0%
Simplified77.0%
Taylor expanded in u2 around 0 67.4%
Final simplification67.4%
herbie shell --seed 2024014
(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))))