
(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 (* (* 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 54.3%
Taylor expanded in u0 around 0
*-commutativeN/A
lower-*.f32N/A
unpow2N/A
lower-*.f3276.1
Applied rewrites76.1%
Final simplification76.1%
(FPCore (alpha u0) :precision binary32 (if (<= u0 0.00015999999595806003) (* (* (- (* (fma -0.5 u0 1.0) u0) (* (- u0) u0)) alpha) alpha) (* (/ (* (* (- alpha) alpha) alpha) alpha) (log (- 1.0 u0)))))
float code(float alpha, float u0) {
float tmp;
if (u0 <= 0.00015999999595806003f) {
tmp = (((fmaf(-0.5f, u0, 1.0f) * u0) - (-u0 * u0)) * alpha) * alpha;
} else {
tmp = (((-alpha * alpha) * alpha) / alpha) * logf((1.0f - u0));
}
return tmp;
}
function code(alpha, u0) tmp = Float32(0.0) if (u0 <= Float32(0.00015999999595806003)) tmp = Float32(Float32(Float32(Float32(fma(Float32(-0.5), u0, Float32(1.0)) * u0) - Float32(Float32(-u0) * u0)) * alpha) * alpha); else tmp = Float32(Float32(Float32(Float32(Float32(-alpha) * alpha) * alpha) / alpha) * log(Float32(Float32(1.0) - u0))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u0 \leq 0.00015999999595806003:\\
\;\;\;\;\left(\left(\mathsf{fma}\left(-0.5, u0, 1\right) \cdot u0 - \left(-u0\right) \cdot u0\right) \cdot \alpha\right) \cdot \alpha\\
\mathbf{else}:\\
\;\;\;\;\frac{\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \alpha}{\alpha} \cdot \log \left(1 - u0\right)\\
\end{array}
\end{array}
if u0 < 1.59999996e-4Initial program 34.7%
Taylor expanded in alpha around 0
unpow2N/A
associate-*l*N/A
*-commutativeN/A
associate-*r*N/A
neg-mul-1N/A
lower-*.f32N/A
distribute-lft-neg-inN/A
mul-1-negN/A
lower-*.f32N/A
mul-1-negN/A
lower-neg.f32N/A
sub-negN/A
lower-log1p.f32N/A
lower-neg.f3292.5
Applied rewrites92.5%
Applied rewrites92.6%
Taylor expanded in u0 around 0
Applied rewrites92.6%
Taylor expanded in u0 around 0
Applied rewrites92.1%
if 1.59999996e-4 < u0 Initial program 87.5%
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
lower-/.f32N/A
lower-*.f3287.6
Applied rewrites87.6%
Final simplification48.5%
(FPCore (alpha u0) :precision binary32 (if (<= u0 0.00015999999595806003) (* (* (- (* (fma -0.5 u0 1.0) u0) (* (- u0) u0)) alpha) alpha) (* (log (- 1.0 u0)) (/ alpha (/ -1.0 alpha)))))
float code(float alpha, float u0) {
float tmp;
if (u0 <= 0.00015999999595806003f) {
tmp = (((fmaf(-0.5f, u0, 1.0f) * u0) - (-u0 * u0)) * alpha) * alpha;
} else {
tmp = logf((1.0f - u0)) * (alpha / (-1.0f / alpha));
}
return tmp;
}
function code(alpha, u0) tmp = Float32(0.0) if (u0 <= Float32(0.00015999999595806003)) tmp = Float32(Float32(Float32(Float32(fma(Float32(-0.5), u0, Float32(1.0)) * u0) - Float32(Float32(-u0) * u0)) * alpha) * alpha); else tmp = Float32(log(Float32(Float32(1.0) - u0)) * Float32(alpha / Float32(Float32(-1.0) / alpha))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u0 \leq 0.00015999999595806003:\\
\;\;\;\;\left(\left(\mathsf{fma}\left(-0.5, u0, 1\right) \cdot u0 - \left(-u0\right) \cdot u0\right) \cdot \alpha\right) \cdot \alpha\\
\mathbf{else}:\\
\;\;\;\;\log \left(1 - u0\right) \cdot \frac{\alpha}{\frac{-1}{\alpha}}\\
\end{array}
\end{array}
if u0 < 1.59999996e-4Initial program 34.7%
Taylor expanded in alpha around 0
unpow2N/A
associate-*l*N/A
*-commutativeN/A
associate-*r*N/A
neg-mul-1N/A
lower-*.f32N/A
distribute-lft-neg-inN/A
mul-1-negN/A
lower-*.f32N/A
mul-1-negN/A
lower-neg.f32N/A
sub-negN/A
lower-log1p.f32N/A
lower-neg.f3292.5
Applied rewrites92.5%
Applied rewrites92.6%
Taylor expanded in u0 around 0
Applied rewrites92.6%
Taylor expanded in u0 around 0
Applied rewrites92.1%
if 1.59999996e-4 < u0 Initial program 87.5%
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-/.f3287.6
Applied rewrites87.6%
Final simplification48.3%
(FPCore (alpha u0) :precision binary32 (if (<= u0 0.00015999999595806003) (* (* (- (* (fma -0.5 u0 1.0) u0) (* (- u0) u0)) alpha) alpha) (* (* (- alpha) alpha) (log (- 1.0 u0)))))
float code(float alpha, float u0) {
float tmp;
if (u0 <= 0.00015999999595806003f) {
tmp = (((fmaf(-0.5f, u0, 1.0f) * u0) - (-u0 * u0)) * alpha) * alpha;
} else {
tmp = (-alpha * alpha) * logf((1.0f - u0));
}
return tmp;
}
function code(alpha, u0) tmp = Float32(0.0) if (u0 <= Float32(0.00015999999595806003)) tmp = Float32(Float32(Float32(Float32(fma(Float32(-0.5), u0, Float32(1.0)) * u0) - Float32(Float32(-u0) * u0)) * alpha) * alpha); else tmp = Float32(Float32(Float32(-alpha) * alpha) * log(Float32(Float32(1.0) - u0))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u0 \leq 0.00015999999595806003:\\
\;\;\;\;\left(\left(\mathsf{fma}\left(-0.5, u0, 1\right) \cdot u0 - \left(-u0\right) \cdot u0\right) \cdot \alpha\right) \cdot \alpha\\
\mathbf{else}:\\
\;\;\;\;\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right)\\
\end{array}
\end{array}
if u0 < 1.59999996e-4Initial program 34.7%
Taylor expanded in alpha around 0
unpow2N/A
associate-*l*N/A
*-commutativeN/A
associate-*r*N/A
neg-mul-1N/A
lower-*.f32N/A
distribute-lft-neg-inN/A
mul-1-negN/A
lower-*.f32N/A
mul-1-negN/A
lower-neg.f32N/A
sub-negN/A
lower-log1p.f32N/A
lower-neg.f3292.5
Applied rewrites92.5%
Applied rewrites92.6%
Taylor expanded in u0 around 0
Applied rewrites92.6%
Taylor expanded in u0 around 0
Applied rewrites92.1%
if 1.59999996e-4 < u0 Initial program 87.5%
Final simplification46.7%
(FPCore (alpha u0) :precision binary32 (if (<= u0 0.00015999999595806003) (* (* (- (* (fma -0.5 u0 1.0) u0) (* (- u0) u0)) alpha) alpha) (* (* (log (- 1.0 u0)) (- alpha)) alpha)))
float code(float alpha, float u0) {
float tmp;
if (u0 <= 0.00015999999595806003f) {
tmp = (((fmaf(-0.5f, u0, 1.0f) * u0) - (-u0 * u0)) * alpha) * alpha;
} else {
tmp = (logf((1.0f - u0)) * -alpha) * alpha;
}
return tmp;
}
function code(alpha, u0) tmp = Float32(0.0) if (u0 <= Float32(0.00015999999595806003)) tmp = Float32(Float32(Float32(Float32(fma(Float32(-0.5), u0, Float32(1.0)) * u0) - Float32(Float32(-u0) * u0)) * alpha) * alpha); else tmp = Float32(Float32(log(Float32(Float32(1.0) - u0)) * Float32(-alpha)) * alpha); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;u0 \leq 0.00015999999595806003:\\
\;\;\;\;\left(\left(\mathsf{fma}\left(-0.5, u0, 1\right) \cdot u0 - \left(-u0\right) \cdot u0\right) \cdot \alpha\right) \cdot \alpha\\
\mathbf{else}:\\
\;\;\;\;\left(\log \left(1 - u0\right) \cdot \left(-\alpha\right)\right) \cdot \alpha\\
\end{array}
\end{array}
if u0 < 1.59999996e-4Initial program 34.7%
Taylor expanded in alpha around 0
unpow2N/A
associate-*l*N/A
*-commutativeN/A
associate-*r*N/A
neg-mul-1N/A
lower-*.f32N/A
distribute-lft-neg-inN/A
mul-1-negN/A
lower-*.f32N/A
mul-1-negN/A
lower-neg.f32N/A
sub-negN/A
lower-log1p.f32N/A
lower-neg.f3292.5
Applied rewrites92.5%
Applied rewrites92.6%
Taylor expanded in u0 around 0
Applied rewrites92.6%
Taylor expanded in u0 around 0
Applied rewrites92.1%
if 1.59999996e-4 < u0 Initial program 87.5%
Taylor expanded in alpha around 0
unpow2N/A
associate-*l*N/A
*-commutativeN/A
associate-*r*N/A
neg-mul-1N/A
lower-*.f32N/A
distribute-lft-neg-inN/A
mul-1-negN/A
lower-*.f32N/A
mul-1-negN/A
lower-neg.f32N/A
sub-negN/A
lower-log1p.f32N/A
lower-neg.f3248.2
Applied rewrites48.2%
Applied rewrites87.5%
Final simplification49.6%
(FPCore (alpha u0) :precision binary32 (* (* (- (* (fma -0.5 u0 1.0) u0) (* (- u0) u0)) alpha) alpha))
float code(float alpha, float u0) {
return (((fmaf(-0.5f, u0, 1.0f) * u0) - (-u0 * u0)) * alpha) * alpha;
}
function code(alpha, u0) return Float32(Float32(Float32(Float32(fma(Float32(-0.5), u0, Float32(1.0)) * u0) - Float32(Float32(-u0) * u0)) * alpha) * alpha) end
\begin{array}{l}
\\
\left(\left(\mathsf{fma}\left(-0.5, u0, 1\right) \cdot u0 - \left(-u0\right) \cdot u0\right) \cdot \alpha\right) \cdot \alpha
\end{array}
Initial program 54.3%
Taylor expanded in alpha around 0
unpow2N/A
associate-*l*N/A
*-commutativeN/A
associate-*r*N/A
neg-mul-1N/A
lower-*.f32N/A
distribute-lft-neg-inN/A
mul-1-negN/A
lower-*.f32N/A
mul-1-negN/A
lower-neg.f32N/A
sub-negN/A
lower-log1p.f32N/A
lower-neg.f3276.1
Applied rewrites76.1%
Applied rewrites76.7%
Taylor expanded in u0 around 0
Applied rewrites76.7%
Taylor expanded in u0 around 0
Applied rewrites76.4%
Final simplification76.7%
herbie shell --seed 2024271
(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))))