
(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 (* alpha (* alpha (- (log1p (- u0))))))
float code(float alpha, float u0) {
return alpha * (alpha * -log1pf(-u0));
}
function code(alpha, u0) return Float32(alpha * Float32(alpha * Float32(-log1p(Float32(-u0))))) end
\begin{array}{l}
\\
\alpha \cdot \left(\alpha \cdot \left(-\mathsf{log1p}\left(-u0\right)\right)\right)
\end{array}
Initial program 56.9%
associate-*l*56.8%
distribute-lft-neg-out56.8%
distribute-rgt-neg-in56.8%
distribute-rgt-neg-in56.8%
distribute-rgt-neg-in56.8%
distribute-lft-neg-out56.8%
sub-neg56.8%
log1p-def99.2%
Simplified99.2%
Final simplification99.2%
(FPCore (alpha u0) :precision binary32 (* alpha (- (* alpha u0) (* (* u0 -0.5) (* alpha u0)))))
float code(float alpha, float u0) {
return alpha * ((alpha * u0) - ((u0 * -0.5f) * (alpha * u0)));
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = alpha * ((alpha * u0) - ((u0 * (-0.5e0)) * (alpha * u0)))
end function
function code(alpha, u0) return Float32(alpha * Float32(Float32(alpha * u0) - Float32(Float32(u0 * Float32(-0.5)) * Float32(alpha * u0)))) end
function tmp = code(alpha, u0) tmp = alpha * ((alpha * u0) - ((u0 * single(-0.5)) * (alpha * u0))); end
\begin{array}{l}
\\
\alpha \cdot \left(\alpha \cdot u0 - \left(u0 \cdot -0.5\right) \cdot \left(\alpha \cdot u0\right)\right)
\end{array}
Initial program 56.9%
associate-*l*56.8%
distribute-lft-neg-out56.8%
distribute-rgt-neg-in56.8%
distribute-rgt-neg-in56.8%
distribute-rgt-neg-in56.8%
distribute-lft-neg-out56.8%
sub-neg56.8%
log1p-def99.2%
Simplified99.2%
Taylor expanded in u0 around 0 87.6%
+-commutative87.6%
fma-def87.6%
*-commutative87.6%
associate-*l*87.6%
Simplified87.6%
Taylor expanded in alpha around -inf 87.6%
mul-1-neg87.6%
neg-mul-187.6%
distribute-rgt-in87.6%
+-commutative87.6%
*-commutative87.6%
unpow287.6%
associate-*r*87.6%
distribute-rgt-in87.6%
neg-mul-187.6%
*-commutative87.6%
+-commutative87.6%
distribute-lft-out87.3%
Simplified87.3%
associate-*r*87.3%
+-commutative87.3%
distribute-rgt-in87.6%
Applied egg-rr87.6%
Final simplification87.6%
(FPCore (alpha u0) :precision binary32 (* alpha (* alpha (* u0 (- (* u0 (- -0.5)) -1.0)))))
float code(float alpha, float u0) {
return alpha * (alpha * (u0 * ((u0 * -(-0.5f)) - -1.0f)));
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = alpha * (alpha * (u0 * ((u0 * -(-0.5e0)) - (-1.0e0))))
end function
function code(alpha, u0) return Float32(alpha * Float32(alpha * Float32(u0 * Float32(Float32(u0 * Float32(-Float32(-0.5))) - Float32(-1.0))))) end
function tmp = code(alpha, u0) tmp = alpha * (alpha * (u0 * ((u0 * -single(-0.5)) - single(-1.0)))); end
\begin{array}{l}
\\
\alpha \cdot \left(\alpha \cdot \left(u0 \cdot \left(u0 \cdot \left(--0.5\right) - -1\right)\right)\right)
\end{array}
Initial program 56.9%
associate-*l*56.8%
distribute-lft-neg-out56.8%
distribute-rgt-neg-in56.8%
distribute-rgt-neg-in56.8%
distribute-rgt-neg-in56.8%
distribute-lft-neg-out56.8%
sub-neg56.8%
log1p-def99.2%
Simplified99.2%
Taylor expanded in u0 around 0 87.6%
+-commutative87.6%
fma-def87.6%
*-commutative87.6%
associate-*l*87.6%
Simplified87.6%
Taylor expanded in alpha around -inf 87.6%
mul-1-neg87.6%
neg-mul-187.6%
distribute-rgt-in87.6%
+-commutative87.6%
*-commutative87.6%
unpow287.6%
associate-*r*87.6%
distribute-rgt-in87.6%
neg-mul-187.6%
*-commutative87.6%
+-commutative87.6%
distribute-lft-out87.3%
Simplified87.3%
Final simplification87.3%
(FPCore (alpha u0) :precision binary32 (* (* alpha alpha) (- u0 (* u0 (* u0 -0.5)))))
float code(float alpha, float u0) {
return (alpha * alpha) * (u0 - (u0 * (u0 * -0.5f)));
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = (alpha * alpha) * (u0 - (u0 * (u0 * (-0.5e0))))
end function
function code(alpha, u0) return Float32(Float32(alpha * alpha) * Float32(u0 - Float32(u0 * Float32(u0 * Float32(-0.5))))) end
function tmp = code(alpha, u0) tmp = (alpha * alpha) * (u0 - (u0 * (u0 * single(-0.5)))); end
\begin{array}{l}
\\
\left(\alpha \cdot \alpha\right) \cdot \left(u0 - u0 \cdot \left(u0 \cdot -0.5\right)\right)
\end{array}
Initial program 56.9%
Taylor expanded in u0 around 0 87.5%
unpow287.5%
associate-*r*87.5%
distribute-rgt-out87.2%
Simplified87.2%
distribute-rgt-in87.5%
mul-1-neg87.5%
*-commutative87.5%
Applied egg-rr87.5%
Final simplification87.5%
(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(alpha * Float32(alpha * u0)) end
function tmp = code(alpha, u0) tmp = alpha * (alpha * u0); end
\begin{array}{l}
\\
\alpha \cdot \left(\alpha \cdot u0\right)
\end{array}
Initial program 56.9%
associate-*l*56.8%
distribute-lft-neg-out56.8%
distribute-rgt-neg-in56.8%
distribute-rgt-neg-in56.8%
distribute-rgt-neg-in56.8%
distribute-lft-neg-out56.8%
sub-neg56.8%
log1p-def99.2%
Simplified99.2%
Taylor expanded in u0 around 0 74.8%
Final simplification74.8%
herbie shell --seed 2023333
(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))))