[petsc-users] DMPlex Parallel Output and DMPlexCreateSection Crashes when DMPlexCreateGmshFromFile used

Mike Michell mi.mike1021 at gmail.com
Tue Apr 26 08:33:20 CDT 2022

Thank you for the answers.
For the first question, basically, I cannot run "/dm/impls/plex/ex1f90.F90"
example with more than 1 proc. I removed DMPlexDistribute() following your
comment and what I tried is:

- no modification to ex1f90.F90 (as it is)
- make "ex1f90"
- mpirun -np 2 ./ex1f90

It gives me "Bad termination of one of ..." for Rank 1. The code runs okay
with "mpirun -np 1 ./ex1f90".


2022년 4월 26일 (화) 오전 3:56, Matthew Knepley <knepley at gmail.com>님이 작성:

> On Mon, Apr 25, 2022 at 9:41 PM Mike Michell <mi.mike1021 at gmail.com>
> wrote:
>> Dear PETSc developer team,
>> I'm trying to learn DMPlex to build a parallel finite volume code in 2D &
>> 3D. More specifically, I want to read a grid from .msh file by Gmsh.
>> For practice, I modified /dm/impls/plex/ex1f90.F90 case to read &
>> distribute my sample 2D grid, which is attached. I have two questions as
>> below:
>> (1) First, if I do not use my grid, but use the default box grid built by
>> ex1f90.F90 and if I try "DMPlexDistribute" over mpi processors, the output
>> file (sol.vtk) has only some portion of the entire mesh. How can I print
>> out the entire thing into a single file? Is there any example for parallel
>> output? (Related files attached to "/Question_1/") Paraview gives me some
>> error messages about data size mismatching.
> For the last release, we made parallel distribution the default. Thus, you
> do not need to call DMPlexDIstribute() explicitly here. Taking it out, I
> can run your example.
>> (2) If I create DMPlex object through "DMPlexCreateGmshFromFile",
>> "DMPlexCreateSection" part is crashed. I do not understand why my example
>> code does not work, because the only change was switching from "DMCreate"
>> to "DMPlexCreateGmshFromFile" and providing "new.msh" file. Without the
>> PetscSection object, the code works fine. Any comments about this? (Related
>> files attached to "/Question_2/")
> If I remove DMPlexDistribute() from this code, it is clear that the
> problem is with the "marker" label. We do not create this by default from
> GMsh since we assume people have defined their own labels. You can pass
>   -dm_plex_gmsh_use_marker
> to your code. WHen I do this, you example runs for me.
>   Thanks,
>     Matt
>> Thanks,
>> Mike
> --
> 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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