If you send the matrix in PETSc binary format we can check this. Matt
On Fri, May 15, 2009 at 12:20 PM, Ryan Yan <vyan2000 at gmail.com> wrote: > Hi all, > I am tring to use the tfs preconditioner to solve a large sparse mpiaij > matrix. > > 11111111111111111111111111111111111111111 > It works very well with a small matrix 45*45(Actually a 9*9 block matrix > with blocksize 5) on 2 processors; Out put is as follows: > > 0 KSP preconditioned resid norm 3.014544557924e+04 true resid norm > 2.219812091849e+04 ||Ae||/||Ax|| 1.000000000000e+00 > 1 KSP preconditioned resid norm 3.679021546908e-03 true resid norm > 1.502747104104e-03 ||Ae||/||Ax|| 6.769704109737e-08 > 2 KSP preconditioned resid norm 2.331909907779e-09 true resid norm > 8.737892755044e-10 ||Ae||/||Ax|| 3.936320910733e-14 > KSP Object: > type: gmres > GMRES: restart=30, using Classical (unmodified) Gram-Schmidt > Orthogonalization with no iterative refinement > GMRES: happy breakdown tolerance 1e-30 > maximum iterations=10000, initial guess is zero > tolerances: relative=1e-10, absolute=1e-50, divergence=10000 > left preconditioning > PC Object: > type: tfs > linear system matrix = precond matrix: > Matrix Object: > type=mpiaij, rows=45, cols=45 > total: nonzeros=825, allocated nonzeros=1350 > using I-node (on process 0) routines: found 5 nodes, limit used is 5 > Norm of error 2.33234e-09, Iterations 2 > > 2222222222222222222222222222222222222222 > > However, when I use the same code for a larger sparse matrix, a 18656 * > 18656 block matrix with blocksize 5); it encounters the followins > error.(Same error message for using 1 and 2 processors, seperately) > > [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<http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#Signal%5B0%5DPETSC>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] PCSetUp_TFS line 116 src/ksp/pc/impls/tfs/tfs.c > [0]PETSC ERROR: [0] PCSetUp line 764 src/ksp/pc/interface/precon.c > [0]PETSC ERROR: [0] KSPSetUp line 183 src/ksp/ksp/interface/itfunc.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 2.3.3, Patch 15, Tue Sep 23 10:02:49 > CDT 2008 HG revision: 31306062cd1a6f6a2496fccb4878f485c9b91760 > [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: ./kspex1reader_binmpiaij on a linux-gnu named > vyan2000-linux by vyan2000 Fri May 15 01:06:12 2009 > [0]PETSC ERROR: Libraries linked from > /home/vyan2000/local/PPETSc/petsc-2.3.3-p15//lib/linux-gnu-c-debug > [0]PETSC ERROR: Configure run at Mon May 4 00:59:41 2009 > [0]PETSC ERROR: Configure options > --with-mpi-dir=/home/vyan2000/local/mpich2-1.0.8p1/ --with-debugger=gdb > --with-shared=0 --download-hypre=1 --download-parmetis=1 > [0]PETSC ERROR: > ------------------------------------------------------------------------ > [0]PETSC ERROR: User provided function() line 0 in unknown directory > unknown file > application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0[cli_0]: > aborting job: > application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0 > > > 3333333333333333333333333333333333333333333333 > > I have the exact solution x in hands, so before I push the matrix into the > ksp solver, I did check the PETSC loaded matrix A and rhs vector b, by > verifying Ax-b=0, in both cases of 1 processor and 2 processors. > > Any sugeestions? > > Thank you very much, > > Yan > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20090515/5a7fc98e/attachment.htm>
