
(FPCore (alpha u0) :precision binary32 (* (* (- alpha) alpha) (log (- 1.0 u0))))
float code(float alpha, float u0) {
return (-alpha * alpha) * logf((1.0f - u0));
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = (-alpha * alpha) * log((1.0e0 - u0))
end function
function code(alpha, u0) return Float32(Float32(Float32(-alpha) * alpha) * log(Float32(Float32(1.0) - u0))) end
function tmp = code(alpha, u0) tmp = (-alpha * alpha) * log((single(1.0) - u0)); end
\begin{array}{l}
\\
\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right)
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 4 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (alpha u0) :precision binary32 (* (* (- alpha) alpha) (log (- 1.0 u0))))
float code(float alpha, float u0) {
return (-alpha * alpha) * logf((1.0f - u0));
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = (-alpha * alpha) * log((1.0e0 - u0))
end function
function code(alpha, u0) return Float32(Float32(Float32(-alpha) * alpha) * log(Float32(Float32(1.0) - u0))) end
function tmp = code(alpha, u0) tmp = (-alpha * alpha) * log((single(1.0) - u0)); end
\begin{array}{l}
\\
\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right)
\end{array}
(FPCore (alpha u0) :precision binary32 (if (<= (- 1.0 u0) 0.9998940229415894) (* (* (/ 1.0 (/ -1.0 alpha)) alpha) (log (- 1.0 u0))) (* (* alpha alpha) u0)))
float code(float alpha, float u0) {
float tmp;
if ((1.0f - u0) <= 0.9998940229415894f) {
tmp = ((1.0f / (-1.0f / alpha)) * alpha) * logf((1.0f - u0));
} else {
tmp = (alpha * alpha) * u0;
}
return tmp;
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
real(4) :: tmp
if ((1.0e0 - u0) <= 0.9998940229415894e0) then
tmp = ((1.0e0 / ((-1.0e0) / alpha)) * alpha) * log((1.0e0 - u0))
else
tmp = (alpha * alpha) * u0
end if
code = tmp
end function
function code(alpha, u0) tmp = Float32(0.0) if (Float32(Float32(1.0) - u0) <= Float32(0.9998940229415894)) tmp = Float32(Float32(Float32(Float32(1.0) / Float32(Float32(-1.0) / alpha)) * alpha) * log(Float32(Float32(1.0) - u0))); else tmp = Float32(Float32(alpha * alpha) * u0); end return tmp end
function tmp_2 = code(alpha, u0) tmp = single(0.0); if ((single(1.0) - u0) <= single(0.9998940229415894)) tmp = ((single(1.0) / (single(-1.0) / alpha)) * alpha) * log((single(1.0) - u0)); else tmp = (alpha * alpha) * u0; end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u0 \leq 0.9998940229415894:\\
\;\;\;\;\left(\frac{1}{\frac{-1}{\alpha}} \cdot \alpha\right) \cdot \log \left(1 - u0\right)\\
\mathbf{else}:\\
\;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u0) < 0.999894023Initial program 84.5%
lift-neg.f32N/A
neg-sub0N/A
flip3--N/A
clear-numN/A
lower-/.f32N/A
metadata-evalN/A
+-lft-identityN/A
mul0-lftN/A
+-rgt-identityN/A
clear-numN/A
+-rgt-identityN/A
mul0-lftN/A
+-lft-identityN/A
metadata-evalN/A
flip3--N/A
neg-sub0N/A
lift-neg.f32N/A
lower-/.f3284.6
Applied rewrites84.6%
if 0.999894023 < (-.f32 #s(literal 1 binary32) u0) Initial program 37.0%
Taylor expanded in u0 around 0
lower-*.f32N/A
unpow2N/A
lower-*.f3290.6
Applied rewrites90.6%
Final simplification88.0%
(FPCore (alpha u0) :precision binary32 (if (<= u0 0.00010599999950500205) (* (* alpha alpha) u0) (* (/ alpha (/ -1.0 alpha)) (log (- 1.0 u0)))))
float code(float alpha, float u0) {
float tmp;
if (u0 <= 0.00010599999950500205f) {
tmp = (alpha * alpha) * u0;
} else {
tmp = (alpha / (-1.0f / alpha)) * logf((1.0f - u0));
}
return tmp;
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
real(4) :: tmp
if (u0 <= 0.00010599999950500205e0) then
tmp = (alpha * alpha) * u0
else
tmp = (alpha / ((-1.0e0) / alpha)) * log((1.0e0 - u0))
end if
code = tmp
end function
function code(alpha, u0) tmp = Float32(0.0) if (u0 <= Float32(0.00010599999950500205)) tmp = Float32(Float32(alpha * alpha) * u0); else tmp = Float32(Float32(alpha / Float32(Float32(-1.0) / alpha)) * log(Float32(Float32(1.0) - u0))); end return tmp end
function tmp_2 = code(alpha, u0) tmp = single(0.0); if (u0 <= single(0.00010599999950500205)) tmp = (alpha * alpha) * u0; else tmp = (alpha / (single(-1.0) / alpha)) * log((single(1.0) - u0)); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u0 \leq 0.00010599999950500205:\\
\;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\
\mathbf{else}:\\
\;\;\;\;\frac{\alpha}{\frac{-1}{\alpha}} \cdot \log \left(1 - u0\right)\\
\end{array}
\end{array}
if u0 < 1.06e-4Initial program 37.0%
Taylor expanded in u0 around 0
lower-*.f32N/A
unpow2N/A
lower-*.f3290.6
Applied rewrites90.6%
if 1.06e-4 < u0 Initial program 84.5%
lift-*.f32N/A
*-commutativeN/A
lift-neg.f32N/A
neg-sub0N/A
flip3--N/A
clear-numN/A
un-div-invN/A
lower-/.f32N/A
metadata-evalN/A
+-lft-identityN/A
mul0-lftN/A
+-rgt-identityN/A
clear-numN/A
+-rgt-identityN/A
mul0-lftN/A
+-lft-identityN/A
metadata-evalN/A
flip3--N/A
neg-sub0N/A
lift-neg.f32N/A
lower-/.f3284.5
Applied rewrites84.5%
Final simplification88.0%
(FPCore (alpha u0) :precision binary32 (if (<= (- 1.0 u0) 0.9998940229415894) (* (* (- alpha) alpha) (log (- 1.0 u0))) (* (* alpha alpha) u0)))
float code(float alpha, float u0) {
float tmp;
if ((1.0f - u0) <= 0.9998940229415894f) {
tmp = (-alpha * alpha) * logf((1.0f - u0));
} else {
tmp = (alpha * alpha) * u0;
}
return tmp;
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
real(4) :: tmp
if ((1.0e0 - u0) <= 0.9998940229415894e0) then
tmp = (-alpha * alpha) * log((1.0e0 - u0))
else
tmp = (alpha * alpha) * u0
end if
code = tmp
end function
function code(alpha, u0) tmp = Float32(0.0) if (Float32(Float32(1.0) - u0) <= Float32(0.9998940229415894)) tmp = Float32(Float32(Float32(-alpha) * alpha) * log(Float32(Float32(1.0) - u0))); else tmp = Float32(Float32(alpha * alpha) * u0); end return tmp end
function tmp_2 = code(alpha, u0) tmp = single(0.0); if ((single(1.0) - u0) <= single(0.9998940229415894)) tmp = (-alpha * alpha) * log((single(1.0) - u0)); else tmp = (alpha * alpha) * u0; end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u0 \leq 0.9998940229415894:\\
\;\;\;\;\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right)\\
\mathbf{else}:\\
\;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u0) < 0.999894023Initial program 84.5%
if 0.999894023 < (-.f32 #s(literal 1 binary32) u0) Initial program 37.0%
Taylor expanded in u0 around 0
lower-*.f32N/A
unpow2N/A
lower-*.f3290.6
Applied rewrites90.6%
(FPCore (alpha u0) :precision binary32 (* (* alpha alpha) u0))
float code(float alpha, float u0) {
return (alpha * alpha) * u0;
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = (alpha * alpha) * u0
end function
function code(alpha, u0) return Float32(Float32(alpha * alpha) * u0) end
function tmp = code(alpha, u0) tmp = (alpha * alpha) * u0; end
\begin{array}{l}
\\
\left(\alpha \cdot \alpha\right) \cdot u0
\end{array}
Initial program 56.8%
Taylor expanded in u0 around 0
lower-*.f32N/A
unpow2N/A
lower-*.f3274.7
Applied rewrites74.7%
herbie shell --seed 2024319
(FPCore (alpha u0)
:name "Beckmann Distribution sample, tan2theta, alphax == alphay"
:precision binary32
:pre (and (and (<= 0.0001 alpha) (<= alpha 1.0)) (and (<= 2.328306437e-10 u0) (<= u0 1.0)))
(* (* (- alpha) alpha) (log (- 1.0 u0))))