
(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 5 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) 0.9869999885559082)
(* (* (* (* alpha alpha) alpha) (/ -1.0 alpha)) (log (- 1.0 u0)))
(*
(*
(*
(-
(* 0.3333333333333333 (* alpha alpha))
(/ (* (* alpha alpha) (+ -0.5 (/ -1.0 u0))) u0))
u0)
u0)
u0)))
float code(float alpha, float u0) {
float tmp;
if ((1.0f - u0) <= 0.9869999885559082f) {
tmp = (((alpha * alpha) * alpha) * (-1.0f / alpha)) * logf((1.0f - u0));
} else {
tmp = ((((0.3333333333333333f * (alpha * alpha)) - (((alpha * alpha) * (-0.5f + (-1.0f / u0))) / u0)) * u0) * u0) * 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) <= 0.9869999885559082e0) then
tmp = (((alpha * alpha) * alpha) * ((-1.0e0) / alpha)) * log((1.0e0 - u0))
else
tmp = ((((0.3333333333333333e0 * (alpha * alpha)) - (((alpha * alpha) * ((-0.5e0) + ((-1.0e0) / u0))) / u0)) * u0) * u0) * u0
end if
code = tmp
end function
function code(alpha, u0) tmp = Float32(0.0) if (Float32(Float32(1.0) - u0) <= Float32(0.9869999885559082)) tmp = Float32(Float32(Float32(Float32(alpha * alpha) * alpha) * Float32(Float32(-1.0) / alpha)) * log(Float32(Float32(1.0) - u0))); else tmp = Float32(Float32(Float32(Float32(Float32(Float32(0.3333333333333333) * Float32(alpha * alpha)) - Float32(Float32(Float32(alpha * alpha) * Float32(Float32(-0.5) + Float32(Float32(-1.0) / u0))) / u0)) * u0) * u0) * u0); end return tmp end
function tmp_2 = code(alpha, u0) tmp = single(0.0); if ((single(1.0) - u0) <= single(0.9869999885559082)) tmp = (((alpha * alpha) * alpha) * (single(-1.0) / alpha)) * log((single(1.0) - u0)); else tmp = ((((single(0.3333333333333333) * (alpha * alpha)) - (((alpha * alpha) * (single(-0.5) + (single(-1.0) / u0))) / u0)) * u0) * u0) * u0; end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u0 \leq 0.9869999885559082:\\
\;\;\;\;\left(\left(\left(\alpha \cdot \alpha\right) \cdot \alpha\right) \cdot \frac{-1}{\alpha}\right) \cdot \log \left(1 - u0\right)\\
\mathbf{else}:\\
\;\;\;\;\left(\left(\left(0.3333333333333333 \cdot \left(\alpha \cdot \alpha\right) - \frac{\left(\alpha \cdot \alpha\right) \cdot \left(-0.5 + \frac{-1}{u0}\right)}{u0}\right) \cdot u0\right) \cdot u0\right) \cdot u0\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u0) < 0.986999989Initial program 95.6%
lift-*.f32N/A
lift-neg.f32N/A
neg-sub0N/A
flip--N/A
metadata-evalN/A
neg-sub0N/A
distribute-lft-neg-outN/A
lift-neg.f32N/A
lift-*.f32N/A
+-lft-identityN/A
associate-*l/N/A
div-invN/A
+-lft-identityN/A
lower-*.f32N/A
lower-*.f32N/A
+-lft-identityN/A
lower-/.f3295.7
Applied rewrites95.7%
if 0.986999989 < (-.f32 #s(literal 1 binary32) u0) Initial program 44.4%
lift-neg.f32N/A
neg-sub0N/A
flip--N/A
metadata-evalN/A
neg-sub0N/A
distribute-lft-neg-outN/A
lift-neg.f32N/A
lift-*.f32N/A
div-invN/A
lower-*.f32N/A
+-lft-identityN/A
lower-/.f3244.4
Applied rewrites44.4%
lift-log.f32N/A
lift--.f32N/A
flip--N/A
log-divN/A
sqr-negN/A
lift-neg.f32N/A
lift-neg.f32N/A
lower--.f32N/A
metadata-evalN/A
lift-neg.f32N/A
lift-neg.f32N/A
sqr-negN/A
cancel-sign-sub-invN/A
lower-log1p.f32N/A
lift-neg.f32N/A
lower-*.f32N/A
lower-log1p.f3281.7
Applied rewrites83.6%
Taylor expanded in u0 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-fma.f32N/A
*-commutativeN/A
associate-*r*N/A
distribute-rgt-outN/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-fma.f32N/A
unpow2N/A
lower-*.f3284.3
Applied rewrites83.8%
Taylor expanded in u0 around -inf
Applied rewrites98.2%
Final simplification97.6%
(FPCore (alpha u0)
:precision binary32
(if (<= (- 1.0 u0) 0.9869999885559082)
(* (* (- alpha) alpha) (log (- 1.0 u0)))
(*
(*
(*
(-
(* 0.3333333333333333 (* alpha alpha))
(/ (* (* alpha alpha) (+ -0.5 (/ -1.0 u0))) u0))
u0)
u0)
u0)))
float code(float alpha, float u0) {
float tmp;
if ((1.0f - u0) <= 0.9869999885559082f) {
tmp = (-alpha * alpha) * logf((1.0f - u0));
} else {
tmp = ((((0.3333333333333333f * (alpha * alpha)) - (((alpha * alpha) * (-0.5f + (-1.0f / u0))) / u0)) * u0) * u0) * 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) <= 0.9869999885559082e0) then
tmp = (-alpha * alpha) * log((1.0e0 - u0))
else
tmp = ((((0.3333333333333333e0 * (alpha * alpha)) - (((alpha * alpha) * ((-0.5e0) + ((-1.0e0) / u0))) / u0)) * u0) * u0) * u0
end if
code = tmp
end function
function code(alpha, u0) tmp = Float32(0.0) if (Float32(Float32(1.0) - u0) <= Float32(0.9869999885559082)) tmp = Float32(Float32(Float32(-alpha) * alpha) * log(Float32(Float32(1.0) - u0))); else tmp = Float32(Float32(Float32(Float32(Float32(Float32(0.3333333333333333) * Float32(alpha * alpha)) - Float32(Float32(Float32(alpha * alpha) * Float32(Float32(-0.5) + Float32(Float32(-1.0) / u0))) / u0)) * u0) * u0) * u0); end return tmp end
function tmp_2 = code(alpha, u0) tmp = single(0.0); if ((single(1.0) - u0) <= single(0.9869999885559082)) tmp = (-alpha * alpha) * log((single(1.0) - u0)); else tmp = ((((single(0.3333333333333333) * (alpha * alpha)) - (((alpha * alpha) * (single(-0.5) + (single(-1.0) / u0))) / u0)) * u0) * u0) * u0; end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u0 \leq 0.9869999885559082:\\
\;\;\;\;\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right)\\
\mathbf{else}:\\
\;\;\;\;\left(\left(\left(0.3333333333333333 \cdot \left(\alpha \cdot \alpha\right) - \frac{\left(\alpha \cdot \alpha\right) \cdot \left(-0.5 + \frac{-1}{u0}\right)}{u0}\right) \cdot u0\right) \cdot u0\right) \cdot u0\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u0) < 0.986999989Initial program 95.6%
if 0.986999989 < (-.f32 #s(literal 1 binary32) u0) Initial program 44.4%
lift-neg.f32N/A
neg-sub0N/A
flip--N/A
metadata-evalN/A
neg-sub0N/A
distribute-lft-neg-outN/A
lift-neg.f32N/A
lift-*.f32N/A
div-invN/A
lower-*.f32N/A
+-lft-identityN/A
lower-/.f3244.4
Applied rewrites44.4%
lift-log.f32N/A
lift--.f32N/A
flip--N/A
log-divN/A
sqr-negN/A
lift-neg.f32N/A
lift-neg.f32N/A
lower--.f32N/A
metadata-evalN/A
lift-neg.f32N/A
lift-neg.f32N/A
sqr-negN/A
cancel-sign-sub-invN/A
lower-log1p.f32N/A
lift-neg.f32N/A
lower-*.f32N/A
lower-log1p.f3283.4
Applied rewrites76.9%
Taylor expanded in u0 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-fma.f32N/A
*-commutativeN/A
associate-*r*N/A
distribute-rgt-outN/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-fma.f32N/A
unpow2N/A
lower-*.f3284.3
Applied rewrites83.8%
Taylor expanded in u0 around -inf
Applied rewrites98.2%
(FPCore (alpha u0)
:precision binary32
(*
(*
(*
(-
(* 0.3333333333333333 (* alpha alpha))
(/ (* (* alpha alpha) (+ -0.5 (/ -1.0 u0))) u0))
u0)
u0)
u0))
float code(float alpha, float u0) {
return ((((0.3333333333333333f * (alpha * alpha)) - (((alpha * alpha) * (-0.5f + (-1.0f / u0))) / u0)) * u0) * u0) * u0;
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = ((((0.3333333333333333e0 * (alpha * alpha)) - (((alpha * alpha) * ((-0.5e0) + ((-1.0e0) / u0))) / u0)) * u0) * u0) * u0
end function
function code(alpha, u0) return Float32(Float32(Float32(Float32(Float32(Float32(0.3333333333333333) * Float32(alpha * alpha)) - Float32(Float32(Float32(alpha * alpha) * Float32(Float32(-0.5) + Float32(Float32(-1.0) / u0))) / u0)) * u0) * u0) * u0) end
function tmp = code(alpha, u0) tmp = ((((single(0.3333333333333333) * (alpha * alpha)) - (((alpha * alpha) * (single(-0.5) + (single(-1.0) / u0))) / u0)) * u0) * u0) * u0; end
\begin{array}{l}
\\
\left(\left(\left(0.3333333333333333 \cdot \left(\alpha \cdot \alpha\right) - \frac{\left(\alpha \cdot \alpha\right) \cdot \left(-0.5 + \frac{-1}{u0}\right)}{u0}\right) \cdot u0\right) \cdot u0\right) \cdot u0
\end{array}
Initial program 56.8%
lift-neg.f32N/A
neg-sub0N/A
flip--N/A
metadata-evalN/A
neg-sub0N/A
distribute-lft-neg-outN/A
lift-neg.f32N/A
lift-*.f32N/A
div-invN/A
lower-*.f32N/A
+-lft-identityN/A
lower-/.f3256.8
Applied rewrites56.8%
lift-log.f32N/A
lift--.f32N/A
flip--N/A
log-divN/A
sqr-negN/A
lift-neg.f32N/A
lift-neg.f32N/A
lower--.f32N/A
metadata-evalN/A
lift-neg.f32N/A
lift-neg.f32N/A
sqr-negN/A
cancel-sign-sub-invN/A
lower-log1p.f32N/A
lift-neg.f32N/A
lower-*.f32N/A
lower-log1p.f3273.1
Applied rewrites72.4%
Taylor expanded in u0 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-fma.f32N/A
*-commutativeN/A
associate-*r*N/A
distribute-rgt-outN/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-fma.f32N/A
unpow2N/A
lower-*.f3272.9
Applied rewrites72.6%
Taylor expanded in u0 around -inf
Applied rewrites88.4%
(FPCore (alpha u0)
:precision binary32
(if (<= (- 1.0 u0) 0.9999780058860779)
(*
(+
(* (* u0 alpha) (* (fma 0.3333333333333333 u0 0.5) alpha))
(* alpha alpha))
u0)
(* (* alpha alpha) u0)))
float code(float alpha, float u0) {
float tmp;
if ((1.0f - u0) <= 0.9999780058860779f) {
tmp = (((u0 * alpha) * (fmaf(0.3333333333333333f, u0, 0.5f) * alpha)) + (alpha * alpha)) * u0;
} else {
tmp = (alpha * alpha) * u0;
}
return tmp;
}
function code(alpha, u0) tmp = Float32(0.0) if (Float32(Float32(1.0) - u0) <= Float32(0.9999780058860779)) tmp = Float32(Float32(Float32(Float32(u0 * alpha) * Float32(fma(Float32(0.3333333333333333), u0, Float32(0.5)) * alpha)) + Float32(alpha * alpha)) * u0); else tmp = Float32(Float32(alpha * alpha) * u0); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u0 \leq 0.9999780058860779:\\
\;\;\;\;\left(\left(u0 \cdot \alpha\right) \cdot \left(\mathsf{fma}\left(0.3333333333333333, u0, 0.5\right) \cdot \alpha\right) + \alpha \cdot \alpha\right) \cdot u0\\
\mathbf{else}:\\
\;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u0) < 0.999978006Initial program 84.5%
lift-neg.f32N/A
neg-sub0N/A
flip--N/A
metadata-evalN/A
neg-sub0N/A
distribute-lft-neg-outN/A
lift-neg.f32N/A
lift-*.f32N/A
div-invN/A
lower-*.f32N/A
+-lft-identityN/A
lower-/.f3284.5
Applied rewrites84.5%
lift-log.f32N/A
lift--.f32N/A
flip--N/A
log-divN/A
sqr-negN/A
lift-neg.f32N/A
lift-neg.f32N/A
lower--.f32N/A
metadata-evalN/A
lift-neg.f32N/A
lift-neg.f32N/A
sqr-negN/A
cancel-sign-sub-invN/A
lower-log1p.f32N/A
lift-neg.f32N/A
lower-*.f32N/A
lower-log1p.f3249.6
Applied rewrites52.0%
Taylor expanded in u0 around 0
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-fma.f32N/A
*-commutativeN/A
associate-*r*N/A
distribute-rgt-outN/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-fma.f32N/A
unpow2N/A
lower-*.f3251.4
Applied rewrites51.0%
Applied rewrites69.7%
if 0.999978006 < (-.f32 #s(literal 1 binary32) u0) Initial program 28.6%
Taylor expanded in u0 around 0
lower-*.f32N/A
unpow2N/A
lower-*.f3294.9
Applied rewrites94.9%
(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-*.f3272.9
Applied rewrites72.9%
herbie shell --seed 2024322
(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))))