[petsc-users] DMPlexCreateSection crashed with larger number of processors

[Matthew Knepley]

On Wed, Jul 6, 2022 at 3:42 PM Mike Michell <mi.mike1021 at gmail.com> wrote:

> I am passing NULL for IS Permutation as;
>
> call
> DMPlexCreateSection(dm_geom,nolabel,pNumComp,pNumDof,numBC,pBcField,pBcCompIS,pBcPointIS,PETSC_NULL_IS,section,ierr)
>
> Should I define non-NULL IS Permutation before I call
> DMPlexCreateSection() to avoid the issue?
>

No, the problem is not the perm argument. To be sure, we should get a stack
trace with line numbers (use a debug build). To me it looked
like you passed a NULL IS to DMAddBoundary().

  Thanks,

    Matt


> Thanks,
> Mike
>
>
> On Wed, Jul 6, 2022 at 12:57 PM Mike Michell <mi.mike1021 at gmail.com>
>> wrote:
>>
>>> Hi, I am using DMPlex for a FVM code written in Fortran that uses
>>> DMPlexCreateSection() to prepare an output file in vtu format. A domain of
>>> interest has around 5000 node points and with small number of processors
>>> (such as nproc=3), the DMPlexCreateSection() works fine. However, if a
>>> larger number of procs (such as nproc=20) is used,  DMPlexCreateSection()
>>> crashes with error message below. It looks very similar problem in a
>>> previous PETSc user inquiry: " [petsc-dev] DMPlexCreateSection crash in
>>> a no-boundary corner case
>>> <https://lists.mcs.anl.gov/pipermail/petsc-dev/2013-November/014049.html>
>>> "
>>>
>>
>> Yes, the recommendation is not to pass a NULL PetscIS to the
>> AddBoundary() routine. Are you doing this?
>>
>>   Thanks,
>>
>>      Matt
>>
>>
>>
>>> When I call DMPlexCreateSection(), a nullified pointer
>>> "nolabel(:)=>NULL()" is provided. What is a possible solution to this
>>> problem? It looks like there is a problem with a processor that does not
>>> have any boundaries. A piece of the source code is attached to show how
>>> the  DMPlexCreateSection() is used in the code.
>>>
>>> Thanks,
>>> Mike
>>>
>>> [16]PETSC ERROR: --------------------- Error Message
>>> --------------------------------------------------------------
>>> [16]PETSC ERROR: Null argument, when expecting valid pointer
>>> [16]PETSC ERROR: Null Pointer: Parameter # 1
>>> [16]PETSC ERROR: See https://petsc.org/release/faq/ for trouble
>>> shooting.
>>> [16]PETSC ERROR: Petsc Release Version 3.17.0, unknown
>>> [16]PETSC ERROR: #1 ISGetLocalSize() at
>>> [16]PETSC ERROR: #2 DMPlexCreateSectionBCDof() at
>>> [16]PETSC ERROR: #3 DMPlexCreateSection() at
>>>
>>
>>
>> --
>> 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
>>
>> https://www.cse.buffalo.edu/~knepley/
>> <http://www.cse.buffalo.edu/~knepley/>
>>
>

-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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