
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ (- (log (- 1.0 u0))) (+ (/ cos2phi (* alphax alphax)) (/ sin2phi (* alphay alphay)))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return -logf((1.0f - u0)) / ((cos2phi / (alphax * alphax)) + (sin2phi / (alphay * alphay)));
}
real(4) function code(alphax, alphay, u0, cos2phi, sin2phi)
real(4), intent (in) :: alphax
real(4), intent (in) :: alphay
real(4), intent (in) :: u0
real(4), intent (in) :: cos2phi
real(4), intent (in) :: sin2phi
code = -log((1.0e0 - u0)) / ((cos2phi / (alphax * alphax)) + (sin2phi / (alphay * alphay)))
end function
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(Float32(-log(Float32(Float32(1.0) - u0))) / Float32(Float32(cos2phi / Float32(alphax * alphax)) + Float32(sin2phi / Float32(alphay * alphay)))) end
function tmp = code(alphax, alphay, u0, cos2phi, sin2phi) tmp = -log((single(1.0) - u0)) / ((cos2phi / (alphax * alphax)) + (sin2phi / (alphay * alphay))); end
\begin{array}{l}
\\
\frac{-\log \left(1 - u0\right)}{\frac{cos2phi}{alphax \cdot alphax} + \frac{sin2phi}{alphay \cdot alphay}}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 7 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ (- (log (- 1.0 u0))) (+ (/ cos2phi (* alphax alphax)) (/ sin2phi (* alphay alphay)))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return -logf((1.0f - u0)) / ((cos2phi / (alphax * alphax)) + (sin2phi / (alphay * alphay)));
}
real(4) function code(alphax, alphay, u0, cos2phi, sin2phi)
real(4), intent (in) :: alphax
real(4), intent (in) :: alphay
real(4), intent (in) :: u0
real(4), intent (in) :: cos2phi
real(4), intent (in) :: sin2phi
code = -log((1.0e0 - u0)) / ((cos2phi / (alphax * alphax)) + (sin2phi / (alphay * alphay)))
end function
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(Float32(-log(Float32(Float32(1.0) - u0))) / Float32(Float32(cos2phi / Float32(alphax * alphax)) + Float32(sin2phi / Float32(alphay * alphay)))) end
function tmp = code(alphax, alphay, u0, cos2phi, sin2phi) tmp = -log((single(1.0) - u0)) / ((cos2phi / (alphax * alphax)) + (sin2phi / (alphay * alphay))); end
\begin{array}{l}
\\
\frac{-\log \left(1 - u0\right)}{\frac{cos2phi}{alphax \cdot alphax} + \frac{sin2phi}{alphay \cdot alphay}}
\end{array}
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ (- (log1p (- u0))) (fma cos2phi (pow alphax -2.0) (* sin2phi (pow alphay -2.0)))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return -log1pf(-u0) / fmaf(cos2phi, powf(alphax, -2.0f), (sin2phi * powf(alphay, -2.0f)));
}
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(Float32(-log1p(Float32(-u0))) / fma(cos2phi, (alphax ^ Float32(-2.0)), Float32(sin2phi * (alphay ^ Float32(-2.0))))) end
\begin{array}{l}
\\
\frac{-\mathsf{log1p}\left(-u0\right)}{\mathsf{fma}\left(cos2phi, {alphax}^{-2}, sin2phi \cdot {alphay}^{-2}\right)}
\end{array}
Initial program 58.0%
distribute-frac-neg58.0%
distribute-neg-frac258.0%
sub-neg58.0%
log1p-define98.4%
neg-sub098.4%
associate--r+98.4%
neg-sub098.4%
associate-/r*98.4%
distribute-neg-frac298.4%
Simplified98.4%
Applied egg-rr97.0%
distribute-rgt-neg-out97.0%
unpow297.0%
rem-3cbrt-lft98.4%
fma-define98.4%
+-commutative98.4%
fma-define98.5%
Simplified98.5%
Final simplification98.5%
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ (- (log1p (- u0))) (+ (/ sin2phi (* alphay alphay)) (* cos2phi (pow alphax -2.0)))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return -log1pf(-u0) / ((sin2phi / (alphay * alphay)) + (cos2phi * powf(alphax, -2.0f)));
}
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(Float32(-log1p(Float32(-u0))) / Float32(Float32(sin2phi / Float32(alphay * alphay)) + Float32(cos2phi * (alphax ^ Float32(-2.0))))) end
\begin{array}{l}
\\
\frac{-\mathsf{log1p}\left(-u0\right)}{\frac{sin2phi}{alphay \cdot alphay} + cos2phi \cdot {alphax}^{-2}}
\end{array}
Initial program 58.0%
distribute-frac-neg58.0%
distribute-neg-frac258.0%
sub-neg58.0%
log1p-define98.4%
neg-sub098.4%
associate--r+98.4%
neg-sub098.4%
associate-/r*98.4%
distribute-neg-frac298.4%
Simplified98.4%
distribute-frac-neg298.4%
associate-/r*98.4%
div-inv98.4%
distribute-lft-neg-in98.4%
pow298.4%
pow-flip98.5%
metadata-eval98.5%
Applied egg-rr98.5%
Final simplification98.5%
(FPCore (alphax alphay u0 cos2phi sin2phi)
:precision binary32
(let* ((t_0 (/ sin2phi (* alphay alphay))))
(if (<= t_0 400.0)
(/
u0
(/
(+ (* alphax (/ sin2phi alphay)) (* alphay (/ cos2phi alphax)))
(* alphax alphay)))
(/ (log1p (- u0)) (- (/ (/ cos2phi alphax) alphax) t_0)))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
float t_0 = sin2phi / (alphay * alphay);
float tmp;
if (t_0 <= 400.0f) {
tmp = u0 / (((alphax * (sin2phi / alphay)) + (alphay * (cos2phi / alphax))) / (alphax * alphay));
} else {
tmp = log1pf(-u0) / (((cos2phi / alphax) / alphax) - t_0);
}
return tmp;
}
function code(alphax, alphay, u0, cos2phi, sin2phi) t_0 = Float32(sin2phi / Float32(alphay * alphay)) tmp = Float32(0.0) if (t_0 <= Float32(400.0)) tmp = Float32(u0 / Float32(Float32(Float32(alphax * Float32(sin2phi / alphay)) + Float32(alphay * Float32(cos2phi / alphax))) / Float32(alphax * alphay))); else tmp = Float32(log1p(Float32(-u0)) / Float32(Float32(Float32(cos2phi / alphax) / alphax) - t_0)); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{sin2phi}{alphay \cdot alphay}\\
\mathbf{if}\;t\_0 \leq 400:\\
\;\;\;\;\frac{u0}{\frac{alphax \cdot \frac{sin2phi}{alphay} + alphay \cdot \frac{cos2phi}{alphax}}{alphax \cdot alphay}}\\
\mathbf{else}:\\
\;\;\;\;\frac{\mathsf{log1p}\left(-u0\right)}{\frac{\frac{cos2phi}{alphax}}{alphax} - t\_0}\\
\end{array}
\end{array}
if (/.f32 sin2phi (*.f32 alphay alphay)) < 400Initial program 51.1%
Taylor expanded in u0 around 0 78.0%
mul-1-neg78.0%
Simplified78.0%
associate-/r*78.0%
div-inv78.0%
Applied egg-rr78.0%
un-div-inv78.0%
associate-/r*78.0%
+-commutative78.0%
associate-/r*78.0%
associate-/r*78.0%
frac-add78.1%
Applied egg-rr78.1%
if 400 < (/.f32 sin2phi (*.f32 alphay alphay)) Initial program 63.7%
distribute-frac-neg63.7%
distribute-neg-frac263.7%
sub-neg63.7%
log1p-define98.1%
neg-sub098.1%
associate--r+98.1%
neg-sub098.1%
associate-/r*98.1%
distribute-neg-frac298.1%
Simplified98.1%
distribute-frac-neg298.1%
associate-/r*98.1%
div-inv98.1%
distribute-lft-neg-in98.1%
pow298.1%
pow-flip98.1%
metadata-eval98.1%
Applied egg-rr98.1%
add-sqr-sqrt-0.0%
sqrt-unprod97.9%
sqr-neg97.9%
sqrt-unprod97.9%
add-sqr-sqrt97.9%
metadata-eval97.9%
pow-flip97.9%
pow297.9%
div-inv97.9%
associate-/r*97.9%
Applied egg-rr97.9%
Final simplification88.9%
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ (log1p (- u0)) (- (/ sin2phi (* alphay (- alphay))) (/ (/ cos2phi alphax) alphax))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return log1pf(-u0) / ((sin2phi / (alphay * -alphay)) - ((cos2phi / alphax) / alphax));
}
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(log1p(Float32(-u0)) / Float32(Float32(sin2phi / Float32(alphay * Float32(-alphay))) - Float32(Float32(cos2phi / alphax) / alphax))) end
\begin{array}{l}
\\
\frac{\mathsf{log1p}\left(-u0\right)}{\frac{sin2phi}{alphay \cdot \left(-alphay\right)} - \frac{\frac{cos2phi}{alphax}}{alphax}}
\end{array}
Initial program 58.0%
distribute-frac-neg58.0%
distribute-neg-frac258.0%
sub-neg58.0%
log1p-define98.4%
neg-sub098.4%
associate--r+98.4%
neg-sub098.4%
associate-/r*98.4%
distribute-neg-frac298.4%
Simplified98.4%
Final simplification98.4%
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ (log1p (- u0)) (- (/ sin2phi (* alphay (- alphay))) (/ cos2phi (* alphax alphax)))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return log1pf(-u0) / ((sin2phi / (alphay * -alphay)) - (cos2phi / (alphax * alphax)));
}
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(log1p(Float32(-u0)) / Float32(Float32(sin2phi / Float32(alphay * Float32(-alphay))) - Float32(cos2phi / Float32(alphax * alphax)))) end
\begin{array}{l}
\\
\frac{\mathsf{log1p}\left(-u0\right)}{\frac{sin2phi}{alphay \cdot \left(-alphay\right)} - \frac{cos2phi}{alphax \cdot alphax}}
\end{array}
Initial program 58.0%
distribute-frac-neg58.0%
distribute-neg-frac258.0%
neg-mul-158.0%
associate-/r*58.0%
remove-double-neg58.0%
distribute-frac-neg58.0%
distribute-neg-frac258.0%
metadata-eval58.0%
/-rgt-identity58.0%
sub-neg58.0%
log1p-define98.4%
Simplified98.4%
Final simplification98.4%
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ u0 (+ (/ sin2phi (* alphay alphay)) (/ cos2phi (* alphax alphax)))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return u0 / ((sin2phi / (alphay * alphay)) + (cos2phi / (alphax * alphax)));
}
real(4) function code(alphax, alphay, u0, cos2phi, sin2phi)
real(4), intent (in) :: alphax
real(4), intent (in) :: alphay
real(4), intent (in) :: u0
real(4), intent (in) :: cos2phi
real(4), intent (in) :: sin2phi
code = u0 / ((sin2phi / (alphay * alphay)) + (cos2phi / (alphax * alphax)))
end function
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(u0 / Float32(Float32(sin2phi / Float32(alphay * alphay)) + Float32(cos2phi / Float32(alphax * alphax)))) end
function tmp = code(alphax, alphay, u0, cos2phi, sin2phi) tmp = u0 / ((sin2phi / (alphay * alphay)) + (cos2phi / (alphax * alphax))); end
\begin{array}{l}
\\
\frac{u0}{\frac{sin2phi}{alphay \cdot alphay} + \frac{cos2phi}{alphax \cdot alphax}}
\end{array}
Initial program 58.0%
Taylor expanded in u0 around 0 76.8%
mul-1-neg76.8%
Simplified76.8%
Final simplification76.8%
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ (* u0 (* alphax alphax)) cos2phi))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return (u0 * (alphax * alphax)) / cos2phi;
}
real(4) function code(alphax, alphay, u0, cos2phi, sin2phi)
real(4), intent (in) :: alphax
real(4), intent (in) :: alphay
real(4), intent (in) :: u0
real(4), intent (in) :: cos2phi
real(4), intent (in) :: sin2phi
code = (u0 * (alphax * alphax)) / cos2phi
end function
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(Float32(u0 * Float32(alphax * alphax)) / cos2phi) end
function tmp = code(alphax, alphay, u0, cos2phi, sin2phi) tmp = (u0 * (alphax * alphax)) / cos2phi; end
\begin{array}{l}
\\
\frac{u0 \cdot \left(alphax \cdot alphax\right)}{cos2phi}
\end{array}
Initial program 58.0%
distribute-frac-neg58.0%
distribute-neg-frac258.0%
sub-neg58.0%
log1p-define98.4%
neg-sub098.4%
associate--r+98.4%
neg-sub098.4%
associate-/r*98.4%
distribute-neg-frac298.4%
Simplified98.4%
Taylor expanded in cos2phi around inf 18.6%
mul-1-neg18.6%
distribute-neg-frac218.6%
sub-neg18.6%
mul-1-neg18.6%
log1p-define23.9%
mul-1-neg23.9%
Simplified23.9%
pow223.9%
Applied egg-rr23.9%
Taylor expanded in u0 around 0 21.0%
mul-1-neg21.0%
Simplified21.0%
Final simplification21.0%
herbie shell --seed 2024050
(FPCore (alphax alphay u0 cos2phi sin2phi)
:name "Beckmann Distribution sample, tan2theta, alphax != alphay, u1 <= 0.5"
:precision binary32
:pre (and (and (and (and (and (<= 0.0001 alphax) (<= alphax 1.0)) (and (<= 0.0001 alphay) (<= alphay 1.0))) (and (<= 2.328306437e-10 u0) (<= u0 1.0))) (and (<= 0.0 cos2phi) (<= cos2phi 1.0))) (<= 0.0 sin2phi))
(/ (- (log (- 1.0 u0))) (+ (/ cos2phi (* alphax alphax)) (/ sin2phi (* alphay alphay)))))