ffc team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Anders Logg wrote:
> On Sat, Dec 06, 2008 at 03:48:34PM +0000, Garth N. Wells wrote:
> > It would be useful if we could somehow associate names with mixed 
> > functions, e.g.
> >
> >    P2 = VectorElement("Lagrange", "triangle", 2)
> >    P1 = FiniteElement("Lagrange", "triangle", 1)
> >    TH = P2 + P1
> >    (u, p, "U") = Functions(TH)
>
> Is it ever necessary to create a Functions that way?
>
> TestFunctions and TrialFunctions are special since they correspond to
> subsets of a bigger system, but for coefficients, one can just do
>
>   u = Function(P2)
>   p = Function(P1)
>
> Even though it seems strange to name two coefficients "u" and "p" for
> Stokes.

With the above they won't share the same vector. It's common that the 
Functions that are of interest in the form will come from solution, for 
example, the solution at previous time steps.

Garth

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