Hi Matt, May I make an inquiry about the file that I send out last week. If there is any thing missing, please let me know. I have other choices on the -pc_type, but it seems like that the 'tfs' is very promising, given it's excellent convergence trajectory when it was applied onto the smaller matrix. Thank you very much, Yan On Fri, May 15, 2009 at 10:46 PM, Ryan Yan <[email protected]> wrote:

Hi Matt, Since the bin file is quit big, I did not post this email to the group. You can reply the next response to the group.

The matrix bin file is in the attachment. petsc_matrix_coef.bin is the bin file to generate the matrix, which have the format aij.

petsc_vec_knownsolu.bin is the bin file to generate the exact solution x.

petsc_vec_rhs.bin is the bin file to generate the right hand side b.

A c script named "tfs_binarymatrix_verify.c" is also attached for your convenience to check Ax-b =0.

If you need any more information, please let me know.

Thank you very much,

Yan

On Fri, May 15, 2009 at 1:34 PM, Matthew Knepley <[email protected]>wrote:

...

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 <[email protected]> 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