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[Martin Sandve Alnæs <martinal@xxxxxxxxx>]

Hi,
this shouldn't be legal, (u,U) and (v,V) here should be derived from
mixed elements to be used in the same form:

e = element + element1
v, V = TestFunctions(e)
u, U = TrialFunctions(e)

I guess we should add some sanity checks for BasisFunctions with
counts < 0 in validate_form().

Or how do you handle this in FFC?

Martin



On Mon, Feb 2, 2009 at 3:06 PM, Kristian Oelgaard
<k.b.oelgaard@xxxxxxxxxx> wrote:
>
> Hello,
>
> Should the following form be legal in UFL?
>
> element = FiniteElement("Lagrange", triangle, 1)
> element1 = VectorElement("Lagrange", triangle, 1)
>
> v = TestFunction(element)
> u = TrialFunction(element)
>
> V = TestFunction(element1)
> U = TrialFunction(element1)
>
> f = Function(element)
>
> a = inner(V, U)*dx + f*v*u*dx
>
> It passes the validate_form() in checks.py
>
> However, extracting basisfunctions yield:
> [BasisFunction(VectorElement('Lagrange', Cell('triangle', 1), 1, 2), -2),
> BasisFunction(VectorElement('Lagrange', Cell('triangle', 1), 1, 2), -1)]
>
> redefining the form:
>
> a = f*inner(V, U)*dx + v*u*dx
>
> The extract basis yield:
>
> [BasisFunction(FiniteElement('Lagrange', Cell('triangle', 1), 1), -2),
> BasisFunction(FiniteElement('Lagrange', Cell('triangle', 1), 1), -1)]
>
>
> Kristian
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