
(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 6 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))) (+ (/ cos2phi (* alphax alphax)) (/ (/ sin2phi alphay) alphay))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return -log1pf(-u0) / ((cos2phi / (alphax * alphax)) + ((sin2phi / alphay) / alphay));
}
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(Float32(-log1p(Float32(-u0))) / Float32(Float32(cos2phi / Float32(alphax * alphax)) + Float32(Float32(sin2phi / alphay) / alphay))) end
\begin{array}{l}
\\
\frac{-\mathsf{log1p}\left(-u0\right)}{\frac{cos2phi}{alphax \cdot alphax} + \frac{\frac{sin2phi}{alphay}}{alphay}}
\end{array}
Initial program 60.1%
sub-neg60.1%
log1p-def98.7%
Simplified98.7%
clear-num98.6%
associate-/r/98.7%
pow298.7%
pow-flip98.8%
metadata-eval98.8%
Applied egg-rr98.8%
*-commutative98.8%
metadata-eval98.8%
pow-flip98.7%
div-inv98.7%
pow298.7%
associate-/r*98.9%
Applied egg-rr98.9%
Final simplification98.9%
(FPCore (alphax alphay u0 cos2phi sin2phi)
:precision binary32
(if (<= (/ sin2phi (* alphay alphay)) 3.9999998989515007e-5)
(/
(* alphax (* u0 alphay))
(+ (/ (* alphax sin2phi) alphay) (/ (* cos2phi alphay) alphax)))
(- (/ (pow alphay 2.0) (- (* sin2phi 0.5) (/ sin2phi u0))))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
float tmp;
if ((sin2phi / (alphay * alphay)) <= 3.9999998989515007e-5f) {
tmp = (alphax * (u0 * alphay)) / (((alphax * sin2phi) / alphay) + ((cos2phi * alphay) / alphax));
} else {
tmp = -(powf(alphay, 2.0f) / ((sin2phi * 0.5f) - (sin2phi / u0)));
}
return tmp;
}
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
real(4) :: tmp
if ((sin2phi / (alphay * alphay)) <= 3.9999998989515007e-5) then
tmp = (alphax * (u0 * alphay)) / (((alphax * sin2phi) / alphay) + ((cos2phi * alphay) / alphax))
else
tmp = -((alphay ** 2.0e0) / ((sin2phi * 0.5e0) - (sin2phi / u0)))
end if
code = tmp
end function
function code(alphax, alphay, u0, cos2phi, sin2phi) tmp = Float32(0.0) if (Float32(sin2phi / Float32(alphay * alphay)) <= Float32(3.9999998989515007e-5)) tmp = Float32(Float32(alphax * Float32(u0 * alphay)) / Float32(Float32(Float32(alphax * sin2phi) / alphay) + Float32(Float32(cos2phi * alphay) / alphax))); else tmp = Float32(-Float32((alphay ^ Float32(2.0)) / Float32(Float32(sin2phi * Float32(0.5)) - Float32(sin2phi / u0)))); end return tmp end
function tmp_2 = code(alphax, alphay, u0, cos2phi, sin2phi) tmp = single(0.0); if ((sin2phi / (alphay * alphay)) <= single(3.9999998989515007e-5)) tmp = (alphax * (u0 * alphay)) / (((alphax * sin2phi) / alphay) + ((cos2phi * alphay) / alphax)); else tmp = -((alphay ^ single(2.0)) / ((sin2phi * single(0.5)) - (sin2phi / u0))); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{sin2phi}{alphay \cdot alphay} \leq 3.9999998989515007 \cdot 10^{-5}:\\
\;\;\;\;\frac{alphax \cdot \left(u0 \cdot alphay\right)}{\frac{alphax \cdot sin2phi}{alphay} + \frac{cos2phi \cdot alphay}{alphax}}\\
\mathbf{else}:\\
\;\;\;\;-\frac{{alphay}^{2}}{sin2phi \cdot 0.5 - \frac{sin2phi}{u0}}\\
\end{array}
\end{array}
if (/.f32 sin2phi (*.f32 alphay alphay)) < 3.9999999e-5Initial program 50.4%
sub-neg50.4%
log1p-def98.7%
Simplified98.7%
+-commutative98.7%
associate-/r*98.9%
associate-/r*99.1%
frac-add98.3%
Applied egg-rr98.3%
Taylor expanded in u0 around 0 79.2%
if 3.9999999e-5 < (/.f32 sin2phi (*.f32 alphay alphay)) Initial program 66.6%
Taylor expanded in cos2phi around 0 64.8%
mul-1-neg64.8%
associate-/l*64.2%
distribute-neg-frac64.2%
sub-neg64.2%
mul-1-neg64.2%
log1p-def94.8%
mul-1-neg94.8%
Simplified94.8%
Taylor expanded in u0 around 0 85.3%
+-commutative85.3%
mul-1-neg85.3%
unsub-neg85.3%
*-commutative85.3%
Simplified85.3%
Final simplification82.8%
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ (- (log1p (- u0))) (+ (/ cos2phi (* alphax alphax)) (/ sin2phi (* alphay alphay)))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return -log1pf(-u0) / ((cos2phi / (alphax * alphax)) + (sin2phi / (alphay * alphay)));
}
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(Float32(-log1p(Float32(-u0))) / Float32(Float32(cos2phi / Float32(alphax * alphax)) + Float32(sin2phi / Float32(alphay * alphay)))) end
\begin{array}{l}
\\
\frac{-\mathsf{log1p}\left(-u0\right)}{\frac{cos2phi}{alphax \cdot alphax} + \frac{sin2phi}{alphay \cdot alphay}}
\end{array}
Initial program 60.1%
sub-neg60.1%
log1p-def98.7%
Simplified98.7%
Final simplification98.7%
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ u0 (+ (/ cos2phi (* alphax alphax)) (/ sin2phi (* alphay alphay)))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return 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 = u0 / ((cos2phi / (alphax * alphax)) + (sin2phi / (alphay * alphay)))
end function
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(u0 / Float32(Float32(cos2phi / Float32(alphax * alphax)) + Float32(sin2phi / Float32(alphay * alphay)))) end
function tmp = code(alphax, alphay, u0, cos2phi, sin2phi) tmp = u0 / ((cos2phi / (alphax * alphax)) + (sin2phi / (alphay * alphay))); end
\begin{array}{l}
\\
\frac{u0}{\frac{cos2phi}{alphax \cdot alphax} + \frac{sin2phi}{alphay \cdot alphay}}
\end{array}
Initial program 60.1%
Taylor expanded in u0 around 0 77.0%
mul-1-neg77.0%
Simplified77.0%
Final simplification77.0%
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (/ u0 (+ (/ cos2phi (* alphax alphax)) (/ (/ sin2phi alphay) alphay))))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return 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 = u0 / ((cos2phi / (alphax * alphax)) + ((sin2phi / alphay) / alphay))
end function
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(u0 / Float32(Float32(cos2phi / Float32(alphax * alphax)) + Float32(Float32(sin2phi / alphay) / alphay))) end
function tmp = code(alphax, alphay, u0, cos2phi, sin2phi) tmp = u0 / ((cos2phi / (alphax * alphax)) + ((sin2phi / alphay) / alphay)); end
\begin{array}{l}
\\
\frac{u0}{\frac{cos2phi}{alphax \cdot alphax} + \frac{\frac{sin2phi}{alphay}}{alphay}}
\end{array}
Initial program 60.1%
sub-neg60.1%
log1p-def98.7%
Simplified98.7%
clear-num98.6%
associate-/r/98.7%
pow298.7%
pow-flip98.8%
metadata-eval98.8%
Applied egg-rr98.8%
*-commutative98.8%
metadata-eval98.8%
pow-flip98.7%
div-inv98.7%
pow298.7%
associate-/r*98.9%
Applied egg-rr98.9%
Taylor expanded in u0 around 0 77.0%
neg-mul-177.0%
Simplified77.0%
Final simplification77.0%
(FPCore (alphax alphay u0 cos2phi sin2phi) :precision binary32 (* (* alphax alphax) (/ u0 cos2phi)))
float code(float alphax, float alphay, float u0, float cos2phi, float sin2phi) {
return (alphax * alphax) * (u0 / 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 = (alphax * alphax) * (u0 / cos2phi)
end function
function code(alphax, alphay, u0, cos2phi, sin2phi) return Float32(Float32(alphax * alphax) * Float32(u0 / cos2phi)) end
function tmp = code(alphax, alphay, u0, cos2phi, sin2phi) tmp = (alphax * alphax) * (u0 / cos2phi); end
\begin{array}{l}
\\
\left(alphax \cdot alphax\right) \cdot \frac{u0}{cos2phi}
\end{array}
Initial program 60.1%
Taylor expanded in u0 around 0 77.0%
mul-1-neg77.0%
Simplified77.0%
associate-/r*77.0%
div-inv76.9%
Applied egg-rr76.9%
Taylor expanded in cos2phi around inf 25.6%
*-lft-identity25.6%
times-frac25.6%
/-rgt-identity25.6%
Simplified25.6%
pow225.6%
Applied egg-rr25.6%
Final simplification25.6%
herbie shell --seed 2023340
(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)))))