
(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 6 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) 0.9700000286102295)
(* (/ (* alpha (* alpha alpha)) (- alpha)) (log (- 1.0 u0)))
(*
(* alpha alpha)
(*
(pow u0 4.0)
(- (/ (- (/ (+ 0.5 (/ 1.0 u0)) u0) -0.3333333333333333) u0) -0.25)))))
float code(float alpha, float u0) {
float tmp;
if ((1.0f - u0) <= 0.9700000286102295f) {
tmp = ((alpha * (alpha * alpha)) / -alpha) * logf((1.0f - u0));
} else {
tmp = (alpha * alpha) * (powf(u0, 4.0f) * (((((0.5f + (1.0f / u0)) / u0) - -0.3333333333333333f) / u0) - -0.25f));
}
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) <= 0.9700000286102295e0) then
tmp = ((alpha * (alpha * alpha)) / -alpha) * log((1.0e0 - u0))
else
tmp = (alpha * alpha) * ((u0 ** 4.0e0) * (((((0.5e0 + (1.0e0 / u0)) / u0) - (-0.3333333333333333e0)) / u0) - (-0.25e0)))
end if
code = tmp
end function
function code(alpha, u0) tmp = Float32(0.0) if (Float32(Float32(1.0) - u0) <= Float32(0.9700000286102295)) tmp = Float32(Float32(Float32(alpha * Float32(alpha * alpha)) / Float32(-alpha)) * log(Float32(Float32(1.0) - u0))); else tmp = Float32(Float32(alpha * alpha) * Float32((u0 ^ Float32(4.0)) * Float32(Float32(Float32(Float32(Float32(Float32(0.5) + Float32(Float32(1.0) / u0)) / u0) - Float32(-0.3333333333333333)) / u0) - Float32(-0.25)))); end return tmp end
function tmp_2 = code(alpha, u0) tmp = single(0.0); if ((single(1.0) - u0) <= single(0.9700000286102295)) tmp = ((alpha * (alpha * alpha)) / -alpha) * log((single(1.0) - u0)); else tmp = (alpha * alpha) * ((u0 ^ single(4.0)) * (((((single(0.5) + (single(1.0) / u0)) / u0) - single(-0.3333333333333333)) / u0) - single(-0.25))); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;1 - u0 \leq 0.9700000286102295:\\
\;\;\;\;\frac{\alpha \cdot \left(\alpha \cdot \alpha\right)}{-\alpha} \cdot \log \left(1 - u0\right)\\
\mathbf{else}:\\
\;\;\;\;\left(\alpha \cdot \alpha\right) \cdot \left({u0}^{4} \cdot \left(\frac{\frac{0.5 + \frac{1}{u0}}{u0} - -0.3333333333333333}{u0} - -0.25\right)\right)\\
\end{array}
\end{array}
if (-.f32 #s(literal 1 binary32) u0) < 0.970000029Initial program 96.8%
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
lower-/.f32N/A
lower-*.f3296.8
lift-*.f32N/A
*-commutativeN/A
lower-*.f3296.8
Applied rewrites96.8%
if 0.970000029 < (-.f32 #s(literal 1 binary32) u0) Initial program 50.5%
Applied rewrites22.6%
Taylor expanded in u0 around 0
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
*-commutativeN/A
metadata-evalN/A
lower-fma.f3281.4
Applied rewrites81.4%
Taylor expanded in u0 around inf
lower-*.f32N/A
lower-pow.f32N/A
sub-negN/A
+-commutativeN/A
distribute-neg-inN/A
metadata-evalN/A
associate-+l+N/A
+-commutativeN/A
unpow2N/A
associate-/r*N/A
associate-/l*N/A
sub-negN/A
associate-*r/N/A
metadata-evalN/A
Applied rewrites98.1%
Final simplification97.9%
(FPCore (alpha u0)
:precision binary32
(if (<= u0 0.005799999926239252)
(*
(* alpha (- alpha))
(*
u0
(+
(+ -1.0 (* u0 (* u0 (fma u0 -0.25 -0.3333333333333333))))
(* u0 -0.5))))
(* (/ (* alpha (* alpha alpha)) (- alpha)) (log (- 1.0 u0)))))
float code(float alpha, float u0) {
float tmp;
if (u0 <= 0.005799999926239252f) {
tmp = (alpha * -alpha) * (u0 * ((-1.0f + (u0 * (u0 * fmaf(u0, -0.25f, -0.3333333333333333f)))) + (u0 * -0.5f)));
} else {
tmp = ((alpha * (alpha * alpha)) / -alpha) * logf((1.0f - u0));
}
return tmp;
}
function code(alpha, u0) tmp = Float32(0.0) if (u0 <= Float32(0.005799999926239252)) tmp = Float32(Float32(alpha * Float32(-alpha)) * Float32(u0 * Float32(Float32(Float32(-1.0) + Float32(u0 * Float32(u0 * fma(u0, Float32(-0.25), Float32(-0.3333333333333333))))) + Float32(u0 * Float32(-0.5))))); else tmp = Float32(Float32(Float32(alpha * Float32(alpha * alpha)) / Float32(-alpha)) * log(Float32(Float32(1.0) - u0))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u0 \leq 0.005799999926239252:\\
\;\;\;\;\left(\alpha \cdot \left(-\alpha\right)\right) \cdot \left(u0 \cdot \left(\left(-1 + u0 \cdot \left(u0 \cdot \mathsf{fma}\left(u0, -0.25, -0.3333333333333333\right)\right)\right) + u0 \cdot -0.5\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\frac{\alpha \cdot \left(\alpha \cdot \alpha\right)}{-\alpha} \cdot \log \left(1 - u0\right)\\
\end{array}
\end{array}
if u0 < 0.00579999993Initial program 46.6%
Applied rewrites22.9%
Taylor expanded in u0 around 0
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
*-commutativeN/A
metadata-evalN/A
lower-fma.f3284.7
Applied rewrites84.7%
lift-fma.f32N/A
lift-fma.f32N/A
+-commutativeN/A
lift-fma.f32N/A
distribute-lft-inN/A
associate-+r+N/A
*-commutativeN/A
lower-+.f32N/A
lower-+.f32N/A
lower-*.f32N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f3298.7
Applied rewrites98.2%
if 0.00579999993 < u0 Initial program 94.0%
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
lower-/.f32N/A
lower-*.f3294.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3294.0
Applied rewrites94.0%
Final simplification70.7%
(FPCore (alpha u0)
:precision binary32
(let* ((t_0 (* alpha (- alpha))))
(if (<= u0 0.005799999926239252)
(*
t_0
(*
u0
(+
(+ -1.0 (* u0 (* u0 (fma u0 -0.25 -0.3333333333333333))))
(* u0 -0.5))))
(* (log (- 1.0 u0)) t_0))))
float code(float alpha, float u0) {
float t_0 = alpha * -alpha;
float tmp;
if (u0 <= 0.005799999926239252f) {
tmp = t_0 * (u0 * ((-1.0f + (u0 * (u0 * fmaf(u0, -0.25f, -0.3333333333333333f)))) + (u0 * -0.5f)));
} else {
tmp = logf((1.0f - u0)) * t_0;
}
return tmp;
}
function code(alpha, u0) t_0 = Float32(alpha * Float32(-alpha)) tmp = Float32(0.0) if (u0 <= Float32(0.005799999926239252)) tmp = Float32(t_0 * Float32(u0 * Float32(Float32(Float32(-1.0) + Float32(u0 * Float32(u0 * fma(u0, Float32(-0.25), Float32(-0.3333333333333333))))) + Float32(u0 * Float32(-0.5))))); else tmp = Float32(log(Float32(Float32(1.0) - u0)) * t_0); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \alpha \cdot \left(-\alpha\right)\\
\mathbf{if}\;u0 \leq 0.005799999926239252:\\
\;\;\;\;t\_0 \cdot \left(u0 \cdot \left(\left(-1 + u0 \cdot \left(u0 \cdot \mathsf{fma}\left(u0, -0.25, -0.3333333333333333\right)\right)\right) + u0 \cdot -0.5\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\log \left(1 - u0\right) \cdot t\_0\\
\end{array}
\end{array}
if u0 < 0.00579999993Initial program 46.6%
Applied rewrites22.9%
Taylor expanded in u0 around 0
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
*-commutativeN/A
metadata-evalN/A
lower-fma.f3284.7
Applied rewrites84.7%
lift-fma.f32N/A
lift-fma.f32N/A
+-commutativeN/A
lift-fma.f32N/A
distribute-lft-inN/A
associate-+r+N/A
*-commutativeN/A
lower-+.f32N/A
lower-+.f32N/A
lower-*.f32N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f3298.7
Applied rewrites98.2%
if 0.00579999993 < u0 Initial program 94.0%
Final simplification70.7%
(FPCore (alpha u0) :precision binary32 (* (* alpha (- alpha)) (* u0 (+ (+ -1.0 (* u0 (* u0 (fma u0 -0.25 -0.3333333333333333)))) (* u0 -0.5)))))
float code(float alpha, float u0) {
return (alpha * -alpha) * (u0 * ((-1.0f + (u0 * (u0 * fmaf(u0, -0.25f, -0.3333333333333333f)))) + (u0 * -0.5f)));
}
function code(alpha, u0) return Float32(Float32(alpha * Float32(-alpha)) * Float32(u0 * Float32(Float32(Float32(-1.0) + Float32(u0 * Float32(u0 * fma(u0, Float32(-0.25), Float32(-0.3333333333333333))))) + Float32(u0 * Float32(-0.5))))) end
\begin{array}{l}
\\
\left(\alpha \cdot \left(-\alpha\right)\right) \cdot \left(u0 \cdot \left(\left(-1 + u0 \cdot \left(u0 \cdot \mathsf{fma}\left(u0, -0.25, -0.3333333333333333\right)\right)\right) + u0 \cdot -0.5\right)\right)
\end{array}
Initial program 57.1%
Applied rewrites22.4%
Taylor expanded in u0 around 0
lower-*.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
metadata-evalN/A
lower-fma.f32N/A
sub-negN/A
*-commutativeN/A
metadata-evalN/A
lower-fma.f3274.8
Applied rewrites74.8%
lift-fma.f32N/A
lift-fma.f32N/A
+-commutativeN/A
lift-fma.f32N/A
distribute-lft-inN/A
associate-+r+N/A
*-commutativeN/A
lower-+.f32N/A
lower-+.f32N/A
lower-*.f32N/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f3291.4
Applied rewrites91.4%
Final simplification91.4%
(FPCore (alpha u0) :precision binary32 (* (/ alpha (/ -1.0 alpha)) (- u0)))
float code(float alpha, float u0) {
return (alpha / (-1.0f / alpha)) * -u0;
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = (alpha / ((-1.0e0) / alpha)) * -u0
end function
function code(alpha, u0) return Float32(Float32(alpha / Float32(Float32(-1.0) / alpha)) * Float32(-u0)) end
function tmp = code(alpha, u0) tmp = (alpha / (single(-1.0) / alpha)) * -u0; end
\begin{array}{l}
\\
\frac{\alpha}{\frac{-1}{\alpha}} \cdot \left(-u0\right)
\end{array}
Initial program 57.1%
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
lower-/.f32N/A
lower-*.f3257.1
lift-*.f32N/A
*-commutativeN/A
lower-*.f3257.1
Applied rewrites57.1%
Taylor expanded in u0 around 0
mul-1-negN/A
lower-neg.f3274.7
Applied rewrites74.7%
Applied rewrites74.6%
Applied rewrites74.8%
(FPCore (alpha u0) :precision binary32 (* u0 (* alpha alpha)))
float code(float alpha, float u0) {
return u0 * (alpha * alpha);
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = u0 * (alpha * alpha)
end function
function code(alpha, u0) return Float32(u0 * Float32(alpha * alpha)) end
function tmp = code(alpha, u0) tmp = u0 * (alpha * alpha); end
\begin{array}{l}
\\
u0 \cdot \left(\alpha \cdot \alpha\right)
\end{array}
Initial program 57.1%
Taylor expanded in u0 around 0
*-commutativeN/A
lower-*.f32N/A
unpow2N/A
lower-*.f3274.8
Applied rewrites74.8%
herbie shell --seed 2024216
(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))))