Hong Zhang wrote: > > k>>> > >>>> >>> >>> >>> >>> >> So ... computation of the preconditioner is actually called by >> KSPSetUp() instead of PCGetFactoredMatrix(prec,&M)? > > > Yes. > >> >> Could you please tell me when the system matrix be factorized >> (incompletely)? thank you. > > > During a call of KSPSetUp(). > > Hong > >> >> Zhifeng >> >> > Thank you for your reply, since the problem I have is ICC took too much memory, but I think I can fix it with reorderring the matrix.
My matrix is SeqSBAIJ and ICC is used as preconditioner, I think the default orderring is "natural", while I think nested-dissection is what I need. However, when I choose nested dissection with - *pc_factor_mat_ordering_type nd, this is what comes out: [0]PETSC ERROR: ------------------------------------------------------------------------ [0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range [0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger [0]PETSC ERROR: or see http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#Signal[0]PETSC ERROR: or try http://valgrind.org on linux or man libgmalloc on Apple to find memory corruption errors [0]PETSC ERROR: likely location of problem given in stack below [0]PETSC ERROR: --------------------- Stack Frames ------------------------------------ [0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available, [0]PETSC ERROR: INSTEAD the line number of the start of the function [0]PETSC ERROR: is given. [0]PETSC ERROR: [0] SPARSEPACKfndsep line 50 src/mat/order/fndsep.c [0]PETSC ERROR: [0] SPARSEPACKgennd line 70 src/mat/order/gennd.c [0]PETSC ERROR: [0] MatOrdering_ND line 18 src/mat/order/spnd.c [0]PETSC ERROR: [0] MatGetOrdering line 187 src/mat/order/sorder.c [0]PETSC ERROR: [0] PCSetup_ICC line 113 src/ksp/pc/impls/factor/icc/icc.c [0]PETSC ERROR: [0] PCSetUp line 778 src/ksp/pc/interface/precon.c [0]PETSC ERROR: [0] KSPSolve line 305 src/ksp/ksp/interface/itfunc.c [0]PETSC ERROR: --------------------- Error Message ------------------------------------ [0]PETSC ERROR: Signal received! [0]PETSC ERROR: ------------------------------------------------------------------------ [0]PETSC ERROR: Petsc Release Version 2.3.2, Patch 10, Wed Mar 28 19:13:22 CDT 2007 HG revision: d7298c71db7f5e767f359ae35d33cab3bed44428 [0]PETSC ERROR: See docs/changes/index.html for recent updates. [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting. [0]PETSC ERROR: See docs/index.html for manual pages. [0]PETSC ERROR: ------------------------------------------------------------------------ [0]PETSC ERROR: bin/main on a linux-gnu named callisto by zhifeng Fri Nov 2 16:00:58 2007 [0]PETSC ERROR: Libraries linked from /u/01/01/zhifeng/install/lib/linux-gnu-c-debug [0]PETSC ERROR: Configure run at Wed Aug 8 13:46:26 2007 [0]PETSC ERROR: Configure options --with-cc=gcc --with-fc=g77 --download-f-blas-lapack=1 --download-mpich=1 --prefix=/u/01/01/zhifeng/install --with-shared=0 [0]PETSC ERROR: ------------------------------------------------------------------------ [0]PETSC ERROR: User provided function() line 0 in unknown directory unknown file [unset]: aborting job: application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0 PS: which reorderring schemas are symmetric? Thanks alot Best regards Zhifeng Sheng *
