Hello! I fear the solution to my problem is obvious, but I think my approach is way too complicated and a dead-end.
I have two different FE systems, one domain surrounding the other one at its outer boundary, but they are codependent. On their common interface they are supposed to "share" dofs, those shall be equal in value at least. (Imagine maybe from structure mechanics a strained body in the middle, somewhat effected by a electrical field / heat and supported on its boundary by strings connecting it to a wall, that behave just differently and aren't effected by this electrical field.) Now what I did is basically create two triangulations with coinciding nodes on the interface and upon that a mapping that can refer from the FEM_A dof_numbers to the FEM_B dof_numbers that have the same position on the interface. Then I assemble a single common system_matrix where I put entries from the FEM_B interface dofs to the mapped FEM_A ones and equal the undefined FEM_B dofs to their partners on FEM_A. This works for my purposes, but I've come to realize that I cannot generate an effective sparsity_pattern this way; my bandwidth of course explodes and I don't know how to renumber dofs effectively... Anyhow I think my approach is not best practice and I was wondering how I can use more deal.ii own methods for my purpose... I guess I could define two DoFHandlers on a single large tria that covers the entire domain and when I iterate over the cells, I use preconditioners to guarantee I only cover those belonging to the respective domain. Then I assemble the system, where I somehow replace the entries from the redundant dofs with the ones from the second DoFHandler (how do I map dof_numbers?) ? Is this the way to go and how would I do that? Or would I use an entirely different approach and maybe create two system_matrices with some kind of connection? Any hint on which way to go would be great, or some tips on where something similar has been done, because I don't recognize an analogue problem within the tutorials... Thank you very much greetings Till _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
