
(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)))) (cos (* 2.0 (pow (pow (* PI u2) 3.0) 0.3333333333333333)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * cosf((2.0f * powf(powf((((float) M_PI) * u2), 3.0f), 0.3333333333333333f)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * cos(Float32(Float32(2.0) * ((Float32(Float32(pi) * u2) ^ Float32(3.0)) ^ Float32(0.3333333333333333))))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \cos \left(2 \cdot {\left({\left(\pi \cdot u2\right)}^{3}\right)}^{0.3333333333333333}\right)
\end{array}
Initial program 55.3%
sub-neg55.3%
log1p-def99.1%
associate-*l*99.1%
Simplified99.1%
add-cbrt-cube99.1%
pow1/399.1%
pow399.1%
Applied egg-rr99.1%
Final simplification99.1%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (* u2 (* 2.0 PI))))
(if (<= t_0 0.0013500000350177288)
(sqrt (- (log1p (- u1))))
(* (cos t_0) (sqrt (+ u1 (* 0.5 (* u1 u1))))))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = u2 * (2.0f * ((float) M_PI));
float tmp;
if (t_0 <= 0.0013500000350177288f) {
tmp = sqrtf(-log1pf(-u1));
} else {
tmp = cosf(t_0) * sqrtf((u1 + (0.5f * (u1 * u1))));
}
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(0.0013500000350177288)) tmp = sqrt(Float32(-log1p(Float32(-u1)))); else tmp = Float32(cos(t_0) * sqrt(Float32(u1 + Float32(Float32(0.5) * Float32(u1 * u1))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := u2 \cdot \left(2 \cdot \pi\right)\\
\mathbf{if}\;t_0 \leq 0.0013500000350177288:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\cos t_0 \cdot \sqrt{u1 + 0.5 \cdot \left(u1 \cdot u1\right)}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.00135000004Initial program 52.5%
sub-neg52.5%
log1p-def99.6%
associate-*l*99.6%
Simplified99.6%
add-cbrt-cube99.6%
pow1/399.6%
pow399.6%
Applied egg-rr99.6%
unpow1/399.6%
rem-cbrt-cube99.6%
*-commutative99.6%
add-cube-cbrt99.6%
associate-*l*99.6%
pow299.6%
Applied egg-rr99.6%
add-log-exp99.6%
associate-*r*99.6%
unpow299.6%
add-cube-cbrt99.6%
Applied egg-rr99.6%
Taylor expanded in u2 around 0 98.9%
if 0.00135000004 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 58.4%
Taylor expanded in u1 around 0 85.9%
+-commutative85.9%
mul-1-neg85.9%
unsub-neg85.9%
unpow285.9%
associate-*r*85.9%
Simplified85.9%
associate-*r*85.9%
add-exp-log85.9%
Applied egg-rr85.9%
Taylor expanded in u2 around inf 85.9%
*-commutative85.9%
*-commutative85.9%
associate-*l*85.9%
unpow285.9%
cancel-sign-sub-inv85.9%
metadata-eval85.9%
Simplified85.9%
Final simplification92.8%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= (* u2 (* 2.0 PI)) 0.009534000419080257) (sqrt (- (log1p (- u1)))) (* (cos (* PI (* 2.0 u2))) (sqrt u1))))
float code(float cosTheta_i, float u1, float u2) {
float tmp;
if ((u2 * (2.0f * ((float) M_PI))) <= 0.009534000419080257f) {
tmp = sqrtf(-log1pf(-u1));
} else {
tmp = cosf((((float) M_PI) * (2.0f * u2))) * sqrtf(u1);
}
return tmp;
}
function code(cosTheta_i, u1, u2) tmp = Float32(0.0) if (Float32(u2 * Float32(Float32(2.0) * Float32(pi))) <= Float32(0.009534000419080257)) tmp = sqrt(Float32(-log1p(Float32(-u1)))); else tmp = Float32(cos(Float32(Float32(pi) * Float32(Float32(2.0) * u2))) * sqrt(u1)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u2 \cdot \left(2 \cdot \pi\right) \leq 0.009534000419080257:\\
\;\;\;\;\sqrt{-\mathsf{log1p}\left(-u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\cos \left(\pi \cdot \left(2 \cdot u2\right)\right) \cdot \sqrt{u1}\\
\end{array}
\end{array}
if (*.f32 (*.f32 2 (PI.f32)) u2) < 0.00953400042Initial program 54.8%
sub-neg54.8%
log1p-def99.5%
associate-*l*99.5%
Simplified99.5%
add-cbrt-cube99.5%
pow1/399.5%
pow399.5%
Applied egg-rr99.5%
unpow1/399.5%
rem-cbrt-cube99.5%
*-commutative99.5%
add-cube-cbrt99.5%
associate-*l*99.5%
pow299.5%
Applied egg-rr99.5%
add-log-exp99.5%
associate-*r*99.5%
unpow299.5%
add-cube-cbrt99.5%
Applied egg-rr99.5%
Taylor expanded in u2 around 0 96.0%
if 0.00953400042 < (*.f32 (*.f32 2 (PI.f32)) u2) Initial program 56.1%
add-sqr-sqrt48.5%
pow248.5%
Applied egg-rr62.6%
Taylor expanded in u1 around 0 75.2%
associate-*r*75.2%
*-commutative75.2%
*-commutative75.2%
Simplified75.2%
Final simplification88.4%
(FPCore (cosTheta_i u1 u2) :precision binary32 (* (sqrt (- (log1p (- u1)))) (cos (* 2.0 (* PI u2)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf(-log1pf(-u1)) * cosf((2.0f * (((float) M_PI) * u2)));
}
function code(cosTheta_i, u1, u2) return Float32(sqrt(Float32(-log1p(Float32(-u1)))) * cos(Float32(Float32(2.0) * Float32(Float32(pi) * u2)))) end
\begin{array}{l}
\\
\sqrt{-\mathsf{log1p}\left(-u1\right)} \cdot \cos \left(2 \cdot \left(\pi \cdot u2\right)\right)
\end{array}
Initial program 55.3%
sub-neg55.3%
log1p-def99.1%
associate-*l*99.1%
Simplified99.1%
Final simplification99.1%
(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 55.3%
sub-neg55.3%
log1p-def99.1%
associate-*l*99.1%
Simplified99.1%
add-cbrt-cube99.1%
pow1/399.1%
pow399.1%
Applied egg-rr99.1%
unpow1/399.1%
rem-cbrt-cube99.1%
*-commutative99.1%
add-cube-cbrt99.0%
associate-*l*99.0%
pow299.0%
Applied egg-rr99.0%
add-log-exp98.9%
associate-*r*98.9%
unpow298.9%
add-cube-cbrt99.1%
Applied egg-rr99.1%
Taylor expanded in u2 around 0 77.6%
Final simplification77.6%
(FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt (+ u1 (* 0.5 (* u1 u1)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf((u1 + (0.5f * (u1 * 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 + (0.5e0 * (u1 * u1))))
end function
function code(cosTheta_i, u1, u2) return sqrt(Float32(u1 + Float32(Float32(0.5) * Float32(u1 * u1)))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt((u1 + (single(0.5) * (u1 * u1)))); end
\begin{array}{l}
\\
\sqrt{u1 + 0.5 \cdot \left(u1 \cdot u1\right)}
\end{array}
Initial program 55.3%
Taylor expanded in u1 around 0 89.1%
+-commutative89.1%
mul-1-neg89.1%
unsub-neg89.1%
unpow289.1%
associate-*r*89.1%
Simplified89.1%
associate-*r*89.1%
add-exp-log89.1%
Applied egg-rr89.1%
Taylor expanded in u2 around 0 72.7%
unpow272.7%
cancel-sign-sub-inv72.7%
metadata-eval72.7%
Simplified72.7%
Final simplification72.7%
(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 55.3%
Taylor expanded in u2 around 0 46.2%
Taylor expanded in u1 around 0 65.2%
mul-1-neg65.2%
Simplified65.2%
Final simplification65.2%
herbie shell --seed 2023215
(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))))