On Thu, Jan 15, 2009 at 10:24 AM, Nguyen, Hung V ERDC-ITL-MS < Hung.V.Nguyen at usace.army.mil> wrote:
> Hello Matt, > > >however I would first check your matrix using -pc_type lu -ksp_type > preonly > to make sure its not singular. > > I got the error message below while running with option above. Do I have to > build a matrix with type of seqaij/seqbaij to run with the -pc_type lu > option? 1) Either run on a single process, or 2) Install a parallel LU, such as SuperLU --download-superlu Matt > > Thanks, > > -Hung > > > > np .. 138524 > np .. 143882 > [0]PETSC ERROR: --------------------- Error Message > ------------------------------------ > [0]PETSC ERROR: [15]PETSC ERROR: [12]PETSC ERROR: [8]PETSC ERROR: > --------------------- Error Message ------------------------------------ > [4]PETSC ERROR: [6]PETSC ERROR: --------------------- Error Message > ------------------------------------ > [13]PETSC ERROR: --------------------- Error Message > ------------------------------------ > --------------------- Error Message ------------------------------------ > [15]PETSC ERROR: [13]PETSC ERROR: No support for this operation for this > object type! > [12]PETSC ERROR: [15]PETSC ERROR: No support for this operation for this > object type! > No support for this operation for this object type! > [12]PETSC ERROR: Matrix type mpiaij symbolic LU! > Matrix type mpiaij symbolic LU! > [13]PETSC ERROR: [15]PETSC ERROR: [12]PETSC ERROR: Matrix type mpiaij > symbolic LU! > [13]PETSC ERROR: > ------------------------------------------------------------------------ > > > > -----Original Message----- > From: owner-petsc-users at mcs.anl.gov [mailto:owner-petsc-users at > mcs.anl.gov] > On > Behalf Of Matthew Knepley > Sent: Wednesday, January 14, 2009 2:05 PM > To: petsc-users at mcs.anl.gov > Subject: Re: Stopping criteria > > On Wed, Jan 14, 2009 at 1:54 PM, Nguyen, Hung V ERDC-ITL-MS > <Hung.V.Nguyen at usace.army.mil> wrote: > > > > Hello All, > > I tried to solve an ill-conditioned system using cg with Jacobi > preconditioned. The KSP solver was stopping due to diverged reason > within a > few iterations. Is there a way to keep KSP solver running until > max_it? > > > There is no way to continue CG here because it gets a zero divisor, and > interprets this as an indefinite matrix. You can try GMRES, however I would > first check your matrix using -pc_type lu -ksp_type preonly to make sure > its > not singular. > > Matt > > > > Thanks, > > -hung > > hvnguyen:jade23% aprun -n 16 ./test_matrix_read -ksp_type cg > -pc_type > jacobi > -ksp_rtol 1.0e-15 -ksp_max_it 50000 -ksp_monitor > -ksp_converged_reason > 0 KSP Residual norm 1.379074550666e+04 > 1 KSP Residual norm 7.252034661743e+03 > 2 KSP Residual norm 7.302184771313e+03 > 3 KSP Residual norm 1.162244351275e+04 > 4 KSP Residual norm 7.912531765659e+03 > 5 KSP Residual norm 4.094706251487e+03 > 6 KSP Residual norm 5.486131070301e+03 > 7 KSP Residual norm 6.367904529202e+03 > 8 KSP Residual norm 6.312767173219e+03 > Linear solve did not converge due to DIVERGED_INDEFINITE_MAT > iterations 9 > Time in PETSc solver: 0.452695 seconds > The number of iteration = 9 > The solution residual error = 6.312767e+03 > > > > > > > -- > 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 > > -- 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/20090115/8cb6edf7/attachment.htm>
