Did you assemble "Neumann" problems that are compatible with your definition of interior/interface degrees of freedom?
Abdullah Ali Sivas <abdullahasi...@gmail.com> writes: > Dear all, > > I have a series of linear systems coming from a PDE for which BDDC is an > optimal preconditioner. These linear systems are assembled and I read them > from a file, then convert into MATIS as required (as in > https://www.mcs.anl.gov/petsc/petsc-current/src/ksp/ksp/examples/tutorials/ex72.c.html > ). I expect each of the systems converge to the solution in almost same > number of iterations but I don't observe it. I think it is because I do not > provide enough information to the preconditioner. I can get a list of inner > dofs and interface dofs. However, I do not know how to use them. Has anyone > have any insights about it or done something similar? > > Best wishes, > Abdullah Ali Sivas
