[petsc-users] Error message for DMShell using MG preconditioner to solve S

[Matthew Knepley]

On Wed, May 21, 2014 at 2:09 PM, Luc Berger-Vergiat <lb2653 at columbia.edu>
wrote:

>  So I just pulled an updated version of petsc-dev today (I switched from
> the *next* branch to the *master* branch due to some compilation error
> existing with the last commit on *next*).
> I still have the same error and I believe this is the whole error message
> I have.
> I mean I am running multiple time steps for my simulation so I have the
> same message at each time step, but I don't think that it is important to
> report these duplicates, is it?
>

Sorry I am just getting back to this. I asked for more of the error
message, because I assumed that some other
PETSc function was calling DMGetGlobalVector(), not you, since you say it
goes away with a different PC. If
you are calling it and its generating this error, it is because you are
calling it before setting a Vec in the DMShell.

  Thanks,

     Matt


> Best,
> Luc
>
> On 05/20/2014 09:14 PM, Matthew Knepley wrote:
>
>
>  On Tue, May 20, 2014 at 4:33 PM, Luc Berger-Vergiat <lb2653 at columbia.edu>
> wrote:
>
>>  Hi all,
>> I am running an FEM simulation that uses Petsc as a linear solver.
>> I am setting up ISs and pass them to a DMShell in order to use the
>> FieldSplit capabilities of Petsc.
>>
>> When I pass the following options to Petsc:
>>
>> " -ksp_type gmres -pc_type fieldsplit -pc_fieldsplit_type schur
>> -pc_fieldsplit_schur_factorization_type full
>> -pc_fieldsplit_schur_precondition selfp -pc_fieldsplit_0_fields 1,2
>> -pc_fieldsplit_1_fields 0 -fieldsplit_0_ksp_type preonly
>> -fieldsplit_0_pc_type ilu -fieldsplit_Field_0_ksp_type gmres
>> -fieldsplit_Field_0_pc_type mg -malloc_log mlog -log_summary time.log"
>>
>> I get an error message:
>>
>> [0]PETSC ERROR: --------------------- Error Message
>> --------------------------------------------------------------
>> [0]PETSC ERROR:
>> [0]PETSC ERROR: Must call DMShellSetGlobalVector() or
>> DMShellSetCreateGlobalVector()
>> [0]PETSC ERROR: See
>> http://http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble
>> shooting.
>> [0]PETSC ERROR: Petsc Development GIT revision: v3.4.4-5071-g1163a46  GIT
>> Date: 2014-03-26 22:20:51 -0500
>> [0]PETSC ERROR: /home/luc/research/feap_repo/ShearBands/parfeap-dev/feap
>> on a arch-linux2-c-opt named euler by luc Tue May 20 11:31:11 2014
>> [0]PETSC ERROR: Configure options --download-cmake --download-hypre
>> --download-metis --download-mpich --download-parmetis --with-debugging=no
>> --with-share-libraries=no
>> [0]PETSC ERROR: #1 DMCreateGlobalVector_Shell() line 245 in
>> /home/luc/research/petsc/src/dm/impls/shell/dmshell.c
>> [0]PETSC ERROR: #2 DMCreateGlobalVector() line 669 in
>> /home/luc/research/petsc/src/dm/interface/dm.c
>> [0]PETSC ERROR: #3 DMGetGlobalVector() line 154 in
>> /home/luc/research/petsc/src/dm/interface/dmget.c
>>
>
>  Always always always give the entire error message.
>
>    Matt
>
>
>>  I am not really sure why this happens but it only happens when
>> -fieldsplit_Field_0_pc_type mg, with other preconditioners, I have no
>> problems. I attached the ksp_view in case that's any use.
>>
>> --
>> Best,
>> Luc
>>
>>
>
>
>  --
> 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
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