On Tue, 29 Jan 2019, Boris Boutkov wrote:
> In short, I cant seem to properly extract the sub-projections needed for GMG > when considering problems with mutiple variables. It seems to me that this is > an issue with maintaining a consistent dof ordering when passing the row and > column index vectors to PetscMatrix::create_submatrix(), an order which needs > to be "in sync" with the ordering of dofs coming from > System::projection_matrix(). How are the orders out of sync, exactly? > For example if I wish to extract the velocity sub-block in a Stokes type > problem, my first attempt was to simply use the > DofMap::local_variable_indices(), concatenating the relevant variable dofs > and passing them to create_submatrix() but this seemed to provide incorrectly > sorted SubMats which later manifests as deteriorated convergence on coarser > grid GMG levels. Are the local_variable_indices results not in ascending order? If not, that would be a bug. If so, what order would you want instead? --- Roy _______________________________________________ Libmesh-devel mailing list Libmesh-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-devel
