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

[Matthew Knepley]

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/>
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