Stopping criteria

[Hong Zhang]

>>
>>> 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
SuperLU is a sequential package.
Use SperLU_DIST or MUMPS. Configure petsc with '--download-superlu_dist' 
or '--download-mumps --download-scalapack --download-blacs'

Hong

>
>
>>
>> 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
>