
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log (- 1.0 u1)))) (cos (* (* 2.0 PI) u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-logf((1.0f - u1))) * cosf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(-log((single(1.0) - u1))) * cos(((single(2.0) * single(pi)) * u2)); end
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \cos \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)))) (cos (* (* 2.0 PI) u2))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-logf((1.0f - u1))) * cosf(((2.0f * ((float) M_PI)) * u2));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log(Float32(Float32(1.0) - u1)))) * cos(Float32(Float32(Float32(2.0) * Float32(pi)) * u2))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(-log((single(1.0) - u1))) * cos(((single(2.0) * single(pi)) * u2)); end
\begin{array}{l}
\\
\sqrt{-\log \left(1 - u1\right)} \cdot \cos \left(\left(2 \cdot \pi\right) \cdot u2\right)
\end{array}
(FPCore (cosTheta_i u1 u2)
:precision binary32
(*
(sqrt (- (log1p (- u1))))
(+
0.5
(-
(* 0.5 (cos (* u2 (* (pow (cbrt PI) 3.0) 2.0))))
(pow (sin (* u2 PI)) 2.0)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * (0.5f + ((0.5f * cosf((u2 * (powf(cbrtf(((float) M_PI)), 3.0f) * 2.0f)))) - powf(sinf((u2 * ((float) M_PI))), 2.0f)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(0.5) + Float32(Float32(Float32(0.5) * cos(Float32(u2 * Float32((cbrt(Float32(pi)) ^ Float32(3.0)) * Float32(2.0))))) - (sin(Float32(u2 * Float32(pi))) ^ Float32(2.0))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(0.5 + \left(0.5 \cdot \cos \left(u2 \cdot \left({\left(\sqrt[3]{\pi}\right)}^{3} \cdot 2\right)\right) - {\sin \left(u2 \cdot \pi\right)}^{2}\right)\right)
\end{array}
Initial program 57.7%
sub-neg57.7%
log1p-def98.8%
Simplified98.8%
add-sqr-sqrt98.6%
pow298.6%
associate-*l*98.6%
Applied egg-rr98.6%
unpow298.6%
add-sqr-sqrt98.8%
cos-298.6%
cancel-sign-sub-inv98.6%
sqr-cos-a98.6%
associate-+l+98.7%
associate-*r*98.7%
*-commutative98.7%
associate-*l*98.7%
Applied egg-rr98.7%
cancel-sign-sub-inv98.7%
unpow298.7%
Simplified98.7%
add-cube-cbrt99.0%
pow399.0%
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(*
(sqrt (- (log1p (- u1))))
(+
0.5
(-
(* 0.5 (cos (* u2 (* PI 2.0))))
(pow (sin (* u2 (pow (cbrt PI) 3.0))) 2.0)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * (0.5f + ((0.5f * cosf((u2 * (((float) M_PI) * 2.0f)))) - powf(sinf((u2 * powf(cbrtf(((float) M_PI)), 3.0f))), 2.0f)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * Float32(Float32(0.5) + Float32(Float32(Float32(0.5) * cos(Float32(u2 * Float32(Float32(pi) * Float32(2.0))))) - (sin(Float32(u2 * (cbrt(Float32(pi)) ^ Float32(3.0)))) ^ Float32(2.0))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \left(0.5 + \left(0.5 \cdot \cos \left(u2 \cdot \left(\pi \cdot 2\right)\right) - {\sin \left(u2 \cdot {\left(\sqrt[3]{\pi}\right)}^{3}\right)}^{2}\right)\right)
\end{array}
Initial program 57.7%
sub-neg57.7%
log1p-def98.8%
Simplified98.8%
add-sqr-sqrt98.6%
pow298.6%
associate-*l*98.6%
Applied egg-rr98.6%
unpow298.6%
add-sqr-sqrt98.8%
cos-298.6%
cancel-sign-sub-inv98.6%
sqr-cos-a98.6%
associate-+l+98.7%
associate-*r*98.7%
*-commutative98.7%
associate-*l*98.7%
Applied egg-rr98.7%
cancel-sign-sub-inv98.7%
unpow298.7%
Simplified98.7%
add-cube-cbrt99.0%
pow399.0%
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (cos (log (exp (* PI (* u2 2.0)))))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * cosf(logf(expf((((float) M_PI) * (u2 * 2.0f)))));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * cos(log(exp(Float32(Float32(pi) * Float32(u2 * Float32(2.0))))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \cos \log \left(e^{\pi \cdot \left(u2 \cdot 2\right)}\right)
\end{array}
Initial program 57.7%
sub-neg57.7%
log1p-def98.8%
Simplified98.8%
add-log-exp98.8%
*-commutative98.8%
exp-prod98.4%
Applied egg-rr98.4%
pow-exp98.8%
*-commutative98.8%
*-commutative98.8%
associate-*l*98.8%
Applied egg-rr98.8%
Final simplification98.8%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* PI 2.0))))
(if (<= t_0 0.009999999776482582)
(sqrt (- (log1p (- u1))))
(* (cos t_0) (sqrt u1)))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (((float) M_PI) * 2.0f);
float tmp;
if (t_0 <= 0.009999999776482582f) {
tmp = sqrtf(-log1pf(-u1));
} else {
tmp = cosf(t_0) * sqrtf(u1);
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(u2 * Float32(Float32(pi) * Float32(2.0))) tmp = Float32(0.0) if (t_0 <= Float32(0.009999999776482582)) tmp = sqrt(Float32(-log1p(Float32(-u1)))); else tmp = Float32(cos(t_0) * sqrt(u1)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(\pi \cdot 2\right)\\
\mathbf{if}\;t_0 \leq 0.009999999776482582:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\cos t_0 \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.00999999978Initial program 57.3%
sub-neg57.3%
log1p-def99.7%
Simplified99.7%
Taylor expanded in u2 around 0 97.0%
if 0.00999999978 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 58.7%
Taylor expanded in u1 around 0 74.7%
mul-1-neg74.7%
Simplified74.7%
Final simplification89.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (cos (* u2 (* PI 2.0)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * cosf((u2 * (((float) M_PI) * 2.0f)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * cos(Float32(u2 * Float32(Float32(pi) * Float32(2.0))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \cos \left(u2 \cdot \left(\pi \cdot 2\right)\right)
\end{array}
Initial program 57.7%
sub-neg57.7%
log1p-def98.8%
Simplified98.8%
Final simplification98.8%
(FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt (- (log1p (- u1)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1));
}
function code(cosTheta_i, u1, u2) return sqrt(Float32(-log1p(Float32(-u1)))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)}
\end{array}
Initial program 57.7%
sub-neg57.7%
log1p-def98.8%
Simplified98.8%
Taylor expanded in u2 around 0 77.1%
Final simplification77.1%
(FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt u1))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(u1);
}
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 = sqrt(u1)
end function
function code(cosTheta_i, u1, u2) return sqrt(u1) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt(u1); end
\begin{array}{l}
\\
\sqrt{u1}
\end{array}
Initial program 57.7%
sub-neg57.7%
log1p-def98.8%
Simplified98.8%
Taylor expanded in u2 around 0 77.1%
add-sqr-sqrt76.4%
pow276.4%
pow1/276.4%
sqrt-pow176.4%
add-sqr-sqrt76.4%
sqrt-unprod76.4%
sqr-neg76.4%
sqrt-unprod-0.0%
add-sqr-sqrt-0.0%
add-sqr-sqrt-0.0%
sqrt-unprod61.3%
sqr-neg61.3%
sqrt-unprod61.3%
add-sqr-sqrt61.3%
metadata-eval61.3%
Applied egg-rr61.3%
Taylor expanded in u1 around 0 62.9%
Final simplification62.9%
herbie shell --seed 2023301
(FPCore (cosTheta_i u1 u2)
:name "Beckmann Sample, near normal, slope_x"
: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)))) (cos (* (* 2.0 PI) u2))))