Dear Praveen,
> For steady state problems, it is recommended to use a block SSOR > preconditioner. This seems to correspond to the AZ_precond = AZ_sym_GS > option in aztec. Am I right ? > > > But if I use this option, I get an error that > > > "sym GS preconditioning can only be used with MSR matrices" The error message basically tells you that you can't use the Aztec preconditioners in conjunction with the matrix format used in TrilinosWrappers::SparseMatrix, which is of type Epetra_CrsMatrix. What you could do is to use a TrilinosWrappers::SolverGMRES object and give it a TrilinosWrappers::SparseMatrix and TrilinosWrappers::PreconditionSSOR. That should work I think. But then you're still using a point-by-point SSOR and not a _block_ SSOR, for which you would need to invert some diagonal blocks. For that we do currently not have any wrapper classes to Trilinos, and the only option would be PreconditionBlock with deal.II sparse matrices. What is the motivation for using Trilinos matrices? Do you plan to run your program in parallel? If not, you can use deal.II matrices just fine with block SSOR. Best, Martin _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
