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

[Mike Michell]

As a follow-up, just "depth" default label was provided to avoid NULL
PETScIS, and it seems working.

Thanks,
Mike


> It looks like NULL PETScIS is obtained from DMGetStratumIS() which is
> shown in the previously attached code. Currently, "marker" label is used to
> define default bcPointIS pointer with numBC=1 through DMGetStratumIS(), and
> it seems that if a certain proc does not have any boundary from this
> "marker" label, the DMPlexCreateSection() crashes.
>
> The PETSc's manual page for DMPlexCreateSection() says "bcPoints" is an IS
> holding points to which each boundary condition applies. So, by including
> no boundary for a certain distributed mesh block, it looks very natural
> that this function crashes. How can I not to pass a NULL PETScIS in this
> case? Is there any specific way for that (or a trick)?
>
> Thanks,
> Mike
>
>
>> 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/>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20220708/6bfd0e20/attachment.html>