Barry, Thanks for the quick reply, that definitely clears it up.
John On Tue, Aug 25, 2009 at 1:38 PM, Barry Smith <bsmith at mcs.anl.gov> wrote: > > The ILU factorization requires a matrix that is created inside the KSP > operations. Plus it counts sequential matrices that are contained inside the > parallel matrices so the matrix numbers will often be hard to understand. > > The VecScatter is created in the MatAssembly and used in the matrix > vector products and then destroyed when the matrix is destroy that is why > its creation and destruction are in different states. > > The index sets in the assembly are used to create the vecscatter. The > index sets in the main stage a probably related to the preconditioner > building. > > Barry > > On Aug 25, 2009, at 1:25 PM, John Fettig wrote: > > I'm trying to understand where matrices get created and destroyed, because >> I have a mismatch in the -log_summary of my code but I can't figure out >> where. Running ksp/ksp/examples/tutorials/ex2 with 4 processors, the log >> summary looks like: >> >> >> >> Object Type Creations Destructions Memory Descendants' Mem. >> >> --- Event Stage 0: Main Stage >> >> Matrix 4 4 11408 0 >> Vec 20 21 29264 0 >> Vec Scatter 0 1 868 0 >> Index Set 3 3 1704 0 >> Krylov Solver 2 2 18880 0 >> Preconditioner 2 2 1408 0 >> >> --- Event Stage 1: Assembly >> >> Vec 2 1 1304 0 >> Vec Scatter 1 0 0 0 >> Index Set 2 2 1052 0 >> >> ======================================================================================================================== >> >> >> Why are there 4 matrices created/destroyed? Where does this happen? I >> only see one matrix being created/destroyed in the source, so it must be >> happening someplace in the KSP/PC. Also, there is a mismatch in the Vec and >> Vec Scatter counts in each of the stages, even though it would seem that >> (e.g.) all the Vec Scatters should be contained to the assembly stage. >> >> John >> >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20090825/b412d516/attachment.htm>
