Hi Martin, > On 22 Nov 2016, at 13:13, Martin Kronbichler <kronbichler.mar...@gmail.com> > wrote: > > Hi Denis, > >> I wonder what is the best workaround given the fact that i have quite a >> number of such vectors? > You only see this for KellyErrorEstimator, right? Given that the error > estimation is much more expensive than the operator evaluation anyway, I would
yes, it’s only for Kelly to get jumps. > suggest you do the copy exactly the way you describe here: > >> Probably the only way is to copy content into a temporary vector, then call >> reinit(locally_owned, locally_relevant, mpi) and assign the content back. >> Then i would use such vectors in Kelly and solution transfer. > You would of course also invoke vector.update_ghost_values(). sure, i do that. > >> Any better ways to accomplish this? Maybe implement/add >> LA::distributed::Vector::set_ghost_set(const IndexSet &) but not sure it's >> worth the effort. > I think the current interface is pretty good after all. Doing one copy is not > that bad. Trilinos does copy the vector to be ghosted for the parallel sparse > matrix-vector product in every operator application. If you want to change > the ghost set, you need to throw away the vector as you note in the next > post. Otherwise, one cannot change the ghost range of the vector. In > addition, changing just the ghost side inside the vector is extremely > dangerous. It took me a few iterations to get the `partitioner_is_compatible` > check work somewhat reliably. The main problem is that local index spaces > with more than one set of ghosts are ambiguous per definition. Besides > deal.II I know two more big projects that have local and global MPI indices > and everyone does the same struggles: You want local indices for performance, > but it's so easy to get things wrong. thanks for the note. One have to be very careful indeed with index sets. Regards, Denis. -- 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 dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
