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[kent-and@xxxxxxxxx]

> It is now possible to take the inverse, absolute value and square root
> of functions in FFC.
>
> The operators are applied directly to the function coefficients so
> this only makes sense for Lagrange elements (and then it only makes
> limited sense for higher order elements).
>
> Here's an example:
>
>   element = FiniteElement("Lagrange", "triangle", 1)
>
>   v = TestFunction(element)
>   u = TrialFunction(element)
>   f = Function(element)
>   g = Function(element)
>
>   a = sqrt(1/abs(1/f))*sqrt(g)*dot(grad(v), grad(u))*dx + \
>       v*u*sqrt(f*g)*g*dx
>
> Pretty cool, but watch out...
>
> /Anders

Very Cool!
So what does
a = 1/f dx
mean ?

Is it based on quadrature such that
a = \sum_i (1/( sum_j f(x_i) N_j(x_i)) w_i,
where x_i and w_i are quadrature nodes and weights
and N_j are the finite element basis?
How do you determine the order of the quadrature?

Kent