
(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 6 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 (* 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 57.9%
sub-neg57.9%
log1p-def99.1%
associate-*l*99.1%
Simplified99.1%
Final simplification99.1%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (- (log (- 1.0 u1)))))
(if (<= t_0 0.0007999999797903001)
(* (cos (* PI (* 2.0 u2))) (sqrt u1))
(sqrt t_0))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = -logf((1.0f - u1));
float tmp;
if (t_0 <= 0.0007999999797903001f) {
tmp = cosf((((float) M_PI) * (2.0f * u2))) * sqrtf(u1);
} else {
tmp = sqrtf(t_0);
}
return tmp;
}
function code(cosTheta_i, u1, u2) t_0 = Float32(-log(Float32(Float32(1.0) - u1))) tmp = Float32(0.0) if (t_0 <= Float32(0.0007999999797903001)) tmp = Float32(cos(Float32(Float32(pi) * Float32(Float32(2.0) * u2))) * sqrt(u1)); else tmp = sqrt(t_0); end return tmp end
function tmp_2 = code(cosTheta_i, u1, u2) t_0 = -log((single(1.0) - u1)); tmp = single(0.0); if (t_0 <= single(0.0007999999797903001)) tmp = cos((single(pi) * (single(2.0) * u2))) * sqrt(u1); else tmp = sqrt(t_0); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := -\log \left(1 - u1\right)\\
\mathbf{if}\;t_0 \leq 0.0007999999797903001:\\
\;\;\;\;\cos \left(\pi \cdot \left(2 \cdot u2\right)\right) \cdot \sqrt{u1}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{t_0}\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 1 u1))) < 7.9999998e-4Initial program 42.8%
add-cube-cbrt42.8%
pow342.8%
Applied egg-rr87.5%
Taylor expanded in u1 around 0 89.7%
pow-base-189.7%
*-lft-identity89.7%
*-commutative89.7%
associate-*r*89.7%
*-commutative89.7%
*-commutative89.7%
Simplified89.7%
if 7.9999998e-4 < (neg.f32 (log.f32 (-.f32 1 u1))) Initial program 92.3%
Taylor expanded in u2 around 0 75.0%
Final simplification85.2%
(FPCore (cosTheta_i u1 u2) :precision binary32 (if (<= (- 1.0 u1) 0.984000027179718) (sqrt (- (log (- 1.0 u1)))) (* (sqrt (- u1 (* u1 (* u1 -0.5)))) (cos (* u2 (* 2.0 PI))))))
float code(float cosTheta_i, float u1, float u2) {
float tmp;
if ((1.0f - u1) <= 0.984000027179718f) {
tmp = sqrtf(-logf((1.0f - u1)));
} else {
tmp = sqrtf((u1 - (u1 * (u1 * -0.5f)))) * cosf((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(0.984000027179718)) tmp = sqrt(Float32(-log(Float32(Float32(1.0) - u1)))); else tmp = Float32(sqrt(Float32(u1 - Float32(u1 * Float32(u1 * Float32(-0.5))))) * cos(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(0.984000027179718)) tmp = sqrt(-log((single(1.0) - u1))); else tmp = sqrt((u1 - (u1 * (u1 * single(-0.5))))) * cos((u2 * (single(2.0) * single(pi)))); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u1 \leq 0.984000027179718:\\
\;\;\;\;\sqrt{-\log \left(1 - u1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{u1 - u1 \cdot \left(u1 \cdot -0.5\right)} \cdot \cos \left(u2 \cdot \left(2 \cdot \pi\right)\right)\\
\end{array}
\end{array}
if (-.f32 1 u1) < 0.984000027Initial program 97.7%
Taylor expanded in u2 around 0 79.4%
if 0.984000027 < (-.f32 1 u1) Initial program 50.1%
Taylor expanded in u1 around 0 96.5%
+-commutative73.6%
mul-1-neg73.6%
unsub-neg73.6%
*-commutative73.6%
unpow273.6%
associate-*l*73.6%
Simplified96.5%
Final simplification93.7%
(FPCore (cosTheta_i u1 u2)
:precision binary32
(let* ((t_0 (- (log (- 1.0 u1)))))
(if (<= t_0 0.0034000000450760126)
(sqrt (- u1 (* u1 (* u1 -0.5))))
(sqrt t_0))))
float code(float cosTheta_i, float u1, float u2) {
float t_0 = -logf((1.0f - u1));
float tmp;
if (t_0 <= 0.0034000000450760126f) {
tmp = sqrtf((u1 - (u1 * (u1 * -0.5f))));
} else {
tmp = sqrtf(t_0);
}
return tmp;
}
real(4) function code(costheta_i, u1, u2)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: u1
real(4), intent (in) :: u2
real(4) :: t_0
real(4) :: tmp
t_0 = -log((1.0e0 - u1))
if (t_0 <= 0.0034000000450760126e0) then
tmp = sqrt((u1 - (u1 * (u1 * (-0.5e0)))))
else
tmp = sqrt(t_0)
end if
code = tmp
end function
function code(cosTheta_i, u1, u2) t_0 = Float32(-log(Float32(Float32(1.0) - u1))) tmp = Float32(0.0) if (t_0 <= Float32(0.0034000000450760126)) tmp = sqrt(Float32(u1 - Float32(u1 * Float32(u1 * Float32(-0.5))))); else tmp = sqrt(t_0); end return tmp end
function tmp_2 = code(cosTheta_i, u1, u2) t_0 = -log((single(1.0) - u1)); tmp = single(0.0); if (t_0 <= single(0.0034000000450760126)) tmp = sqrt((u1 - (u1 * (u1 * single(-0.5))))); else tmp = sqrt(t_0); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := -\log \left(1 - u1\right)\\
\mathbf{if}\;t_0 \leq 0.0034000000450760126:\\
\;\;\;\;\sqrt{u1 - u1 \cdot \left(u1 \cdot -0.5\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{t_0}\\
\end{array}
\end{array}
if (neg.f32 (log.f32 (-.f32 1 u1))) < 0.00340000005Initial program 46.5%
Taylor expanded in u2 around 0 40.0%
Taylor expanded in u1 around 0 74.5%
+-commutative74.5%
mul-1-neg74.5%
unsub-neg74.5%
*-commutative74.5%
unpow274.5%
associate-*l*74.5%
Simplified74.5%
if 0.00340000005 < (neg.f32 (log.f32 (-.f32 1 u1))) Initial program 95.1%
Taylor expanded in u2 around 0 76.4%
Final simplification74.9%
(FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt (- u1 (* u1 (* u1 -0.5)))))
float code(float cosTheta_i, float u1, float u2) {
return sqrtf((u1 - (u1 * (u1 * -0.5f))));
}
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 - (u1 * (u1 * (-0.5e0)))))
end function
function code(cosTheta_i, u1, u2) return sqrt(Float32(u1 - Float32(u1 * Float32(u1 * Float32(-0.5))))) end
function tmp = code(cosTheta_i, u1, u2) tmp = sqrt((u1 - (u1 * (u1 * single(-0.5))))); end
\begin{array}{l}
\\
\sqrt{u1 - u1 \cdot \left(u1 \cdot -0.5\right)}
\end{array}
Initial program 57.9%
Taylor expanded in u2 around 0 48.5%
Taylor expanded in u1 around 0 69.2%
+-commutative69.2%
mul-1-neg69.2%
unsub-neg69.2%
*-commutative69.2%
unpow269.2%
associate-*l*69.2%
Simplified69.2%
Final simplification69.2%
(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 57.9%
Taylor expanded in u2 around 0 48.5%
sub-neg48.5%
log1p-udef75.9%
add-cbrt-cube75.9%
pow1/374.3%
Applied egg-rr59.4%
Taylor expanded in u1 around 0 61.6%
Final simplification61.6%
herbie shell --seed 2023278
(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))))