Bhanu,

In my application, the FESystem is 'fe(FE_Q<dim>(degree+1), dim, FE_Q<dim>(degree), 1, FE_Q<dim>(degree), dim)'. As you can see there are three unknown solution variables(lets call them U, p and W), in which the first and last are vector valued with 'dim' components and the first one is one degree higher than the last. The boundary condition/constraint I have is 'W = U' in every component at a particular boundary with boundary_id. (U dof is present at every W dof as U is one degree higher than W, but not the other way).

This is not actually true, and it's going to make the algorithm you are seeking substantially more complicated. Think about a Q3 element for U and a Q2 element for W: U has nodes at 1/3 and 2/3 along each edge, but W has nodes only at the midpoint of each edge.

So the algorithm you're seeking cannot be as simple as set some degrees of freedom equal to others, and the rest to zero. Rather, the problem you want to solve is in essence what one does in hp finite element methods where you have a Q3 and a Q2 element coming together at one edge. You may want to read the paper I wrote with Oliver Kayser-Herold many years ago about this.

An alternative could be to use FE_Q_Hierarchical instead. That one, truly, satisfies the property you describe and would make construction of these constraints easier.

Best
 W.

--
------------------------------------------------------------------------
Wolfgang Bangerth          email:                 [email protected]
                           www: http://www.math.colostate.edu/~bangerth/

--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- You received this message because you are subscribed to the Google Groups "deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
For more options, visit https://groups.google.com/d/optout.

Reply via email to