
(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)) (log1p (- u0))))
float code(float alpha, float u0) {
return (alpha * -alpha) * log1pf(-u0);
}
function code(alpha, u0) return Float32(Float32(alpha * Float32(-alpha)) * log1p(Float32(-u0))) end
\begin{array}{l}
\\
\left(\alpha \cdot \left(-\alpha\right)\right) \cdot \mathsf{log1p}\left(-u0\right)
\end{array}
Initial program 59.9%
*-commutative59.9%
sub-neg59.9%
log1p-def99.1%
Simplified99.1%
Final simplification99.1%
(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 59.9%
associate-*l*59.9%
sub-neg59.9%
log1p-def99.1%
Simplified99.1%
Final simplification99.1%
(FPCore (alpha u0) :precision binary32 (* alpha (* alpha (+ u0 (* (* u0 u0) (+ 0.5 (* u0 0.3333333333333333)))))))
float code(float alpha, float u0) {
return alpha * (alpha * (u0 + ((u0 * u0) * (0.5f + (u0 * 0.3333333333333333f)))));
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = alpha * (alpha * (u0 + ((u0 * u0) * (0.5e0 + (u0 * 0.3333333333333333e0)))))
end function
function code(alpha, u0) return Float32(alpha * Float32(alpha * Float32(u0 + Float32(Float32(u0 * u0) * Float32(Float32(0.5) + Float32(u0 * Float32(0.3333333333333333))))))) end
function tmp = code(alpha, u0) tmp = alpha * (alpha * (u0 + ((u0 * u0) * (single(0.5) + (u0 * single(0.3333333333333333)))))); end
\begin{array}{l}
\\
\alpha \cdot \left(\alpha \cdot \left(u0 + \left(u0 \cdot u0\right) \cdot \left(0.5 + u0 \cdot 0.3333333333333333\right)\right)\right)
\end{array}
Initial program 59.9%
associate-*l*59.9%
sub-neg59.9%
log1p-def99.1%
Simplified99.1%
Taylor expanded in u0 around 0 91.9%
associate-+r+91.9%
+-commutative91.9%
+-commutative91.9%
associate-*r*91.9%
associate-*r*91.9%
distribute-rgt-out91.9%
associate-*r*91.9%
distribute-rgt-out91.9%
unpow291.9%
unpow291.9%
unpow291.9%
Simplified91.9%
Taylor expanded in u0 around 0 89.5%
unpow289.5%
unpow289.5%
associate-*r*89.5%
cube-mult89.5%
associate-*l*89.5%
associate-*l*89.5%
unpow289.5%
unpow289.5%
distribute-rgt-in89.5%
+-commutative89.5%
*-commutative89.5%
associate-*l*89.5%
*-commutative89.5%
Simplified89.5%
Final simplification89.5%
(FPCore (alpha u0) :precision binary32 (* (* alpha alpha) (+ u0 (* (* u0 u0) (+ 0.5 (* u0 0.3333333333333333))))))
float code(float alpha, float u0) {
return (alpha * alpha) * (u0 + ((u0 * u0) * (0.5f + (u0 * 0.3333333333333333f))));
}
real(4) function code(alpha, u0)
real(4), intent (in) :: alpha
real(4), intent (in) :: u0
code = (alpha * alpha) * (u0 + ((u0 * u0) * (0.5e0 + (u0 * 0.3333333333333333e0))))
end function
function code(alpha, u0) return Float32(Float32(alpha * alpha) * Float32(u0 + Float32(Float32(u0 * u0) * Float32(Float32(0.5) + Float32(u0 * Float32(0.3333333333333333)))))) end
function tmp = code(alpha, u0) tmp = (alpha * alpha) * (u0 + ((u0 * u0) * (single(0.5) + (u0 * single(0.3333333333333333))))); end
\begin{array}{l}
\\
\left(\alpha \cdot \alpha\right) \cdot \left(u0 + \left(u0 \cdot u0\right) \cdot \left(0.5 + u0 \cdot 0.3333333333333333\right)\right)
\end{array}
Initial program 59.9%
associate-*l*59.9%
sub-neg59.9%
log1p-def99.1%
Simplified99.1%
Taylor expanded in u0 around 0 89.5%
*-commutative89.5%
+-commutative89.5%
associate-*r*89.5%
associate-*r*89.5%
distribute-rgt-out89.5%
distribute-lft-out89.5%
unpow289.5%
cube-mult89.5%
unpow289.5%
associate-*r*89.5%
distribute-rgt-out89.5%
unpow289.5%
Simplified89.5%
Final simplification89.5%
(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(Float32(u0 * 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 + \left(u0 \cdot u0\right) \cdot 0.5\right)
\end{array}
Initial program 59.9%
associate-*l*59.9%
sub-neg59.9%
log1p-def99.1%
Simplified99.1%
Taylor expanded in u0 around 0 85.3%
+-commutative85.3%
associate-*r*85.3%
distribute-rgt-out85.4%
unpow285.4%
unpow285.4%
Simplified85.4%
Final simplification85.4%
(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 59.9%
associate-*l*59.9%
sub-neg59.9%
log1p-def99.1%
Simplified99.1%
Taylor expanded in u0 around 0 72.2%
*-commutative72.2%
unpow272.2%
associate-*l*72.3%
Simplified72.3%
Final simplification72.3%
herbie shell --seed 2023255
(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))))