On Mon, Jun 20, 2011 at 16:26, Gianluca Meneghello <gianmail at gmail.com>wrote:
> My goal is to perform some relaxation sweeps for each ordering at each > level of a multigrid process, probably using ksptype PREONLY and > pctype ILU. > Is that possible? > Yes, but you would need to perform a separate factorization for each ordering. Also, the orderings that are not aligned with the grid in memory will have poor performance. This is a general problem with using different orderings. Is there the equivalent of -pc_sor_its with ILU > (-pc_ilu_its maybe)? > -ksp_type richardson is the same thing, put it inside -pc_type bjacobi for -pc_sor_lits. (-pc_sor_its is just a lower overhead way to do that cycling). > I also have the problem that in order to build the ordering I would > need to have access to a structure containing some grid informations, > and it seems I cannot pass that structure to the YourOrdering function > you suggested. > You can PetscObjectCompose() your structure to the Mat. You might need PetscContainerCreate() to wrap your struct. > > I guess a solution for me could be to build the IS from an external > function (not used by petsc) and then attach them directly to the mat > structure. I also guess that the one to use are the ones at line 36 of > No, those slots are not public. Use PetscObjectCompose(). -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110620/062d26e4/attachment.htm>
