Another similar question. Running src/snes/examples/tutorials/ex1 on 2 processors with -log_summary shows
VecScatterBegin 91 1.0 1.2181e-03 1.3 0.00e+00 0.0 3.8e+01 8.0e+00 0.0e+00 4 0 49 40 0 4 0 49 40 0 0 VecScatterEnd 19 1.0 3.5119e-04 3.5 0.00e+00 0.0 0.0e+00 0.0e+00 0.0e+00 1 0 0 0 0 1 0 0 0 0 0 There are 91 Begins but only 19 Ends. The calls are matched in the driver, so why aren't they matched when it runs? John On Tue, Aug 25, 2009 at 1:42 PM, John Fettig <john.fettig at gmail.com> wrote: > 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/20090825/30a49f1b/attachment-0001.htm>
