[dune-fem] How to get DoFs for Dirichlet nodes with vector-valued unknowns

[Sacconi, Andrea]

Hi all,

I have a quick question for you.

Suppose you need to find the global DoFs associated to the Dirichlet nodes. The purpose is, of course, to modify the rows of the stiffness matrix in the standard way, as well as the corresponding components on the rhs.
When the unknown is a scalar variable, I don't have problems: I loop over the entities, extract the LagrangePointSetType set for each entity, use FaceDofIteratorType, ...

But when the unknown is a vector-valued function, how do I proceed? I have tried to do exactly the same, and I noticed that the same node can refer to two different DoFs.
The problem is, how do I prescribe the value for the function? Since it's a vector-valued function, where do I prescribe the first component and where the second?
In other words, how is the DoFs set created?

Thanks in advance for your help!

Cheers,
Andrea


__________________________________________________________

Andrea Sacconi
PhD student, Applied Mathematics
AMMP Section, Department of Mathematics, Imperial College London,
London SW7 2AZ, UK
a.sacconi11 at imperial.ac.uk
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