[petsc-users] DMPLEX Field name changes after getting a Vec

[Pierre Seize]

Thank you, the fix works fine indeed. 

Pierre Seize 

Le 2020-04-01 13:15, Matthew Knepley a écrit :

> On Wed, Apr 1, 2020 at 5:34 AM Pierre Seize <pierre.seize at onera.fr> wrote: 
> 
>> Hello everyone. 
>> 
>> I noticed a strange feature, and I don't know if it is a small bug or if it is expected behaviour. 
>> 
>> I have a DMPLEX read from a file, and I add a PetscFV field to it. For debugging purposes I want to name this PetscFV with PetscObjectSetName. But when later I create a global vector, the name of the field gets erased. Is it to be expected ?
> 
> You are right. It is a bug. I have made a merge request for this fix here: 
> 
> https://gitlab.com/petsc/petsc/-/merge_requests/2670 
> 
> and it seems to work on your example: 
> 
> master *:~/Downloads/tmp/Pierre$ ./names 
> 
> DM Object: Mesh 1 MPI processes 
> 
> type: plex 
> 
> Mesh in 0 dimensions: 
> 
> Labels: 
> 
> celltype: 0 strata with value/size () 
> 
> Field FV Model: 
> 
> adjacency FVM 
> 
> DM Object: Mesh 1 MPI processes 
> 
> type: plex 
> 
> Mesh in 0 dimensions: 
> 
> Labels: 
> 
> celltype: 0 strata with value/size () 
> 
> Field FV Model: 
> 
> adjacency FVM 
> 
> The reason for this behavior was that originally, FEM people named the fields individually, but 
> FV people tended to have one field with the physical fields being components so that they could 
> have a single Riemann solve for all fields. Now you can name field components, so this does not 
> matter anymore. 
> 
> Thanks, 
> 
> Matt  
> 
>> Here is a minimal working example: 
>> 
>> #include <petscdmplex.h>
>> int main(int argc, char **argv){
>> PetscErrorCode    ierr;
>> 
>> DM      dm;
>> PetscFV fvm;
>> Vec     x;
>> 
>> ierr = PetscInitialize(&argc, &argv, NULL, NULL); if (ierr) return ierr;
>> ierr = DMCreate(PETSC_COMM_WORLD, &dm);                   CHKERRQ(ierr);
>> ierr = DMSetType(dm, DMPLEX);                             CHKERRQ(ierr);
>> ierr = PetscFVCreate(PETSC_COMM_WORLD, &fvm);             CHKERRQ(ierr);
>> ierr = DMAddField(dm, NULL, (PetscObject) fvm);           CHKERRQ(ierr);
>> ierr = PetscObjectSetName((PetscObject) fvm, "FV Model"); CHKERRQ(ierr);
>> ierr = DMView(dm, PETSC_VIEWER_STDOUT_WORLD);             CHKERRQ(ierr); <- Here the field is named "FV Model"
>> ierr = DMCreateGlobalVector(dm, &x);                      CHKERRQ(ierr);
>> ierr = DMView(dm, PETSC_VIEWER_STDOUT_WORLD);             CHKERRQ(ierr); <- Here the field is named "Field_0"
>> 
>> ierr = VecDestroy(&x);       CHKERRQ(ierr);
>> ierr = PetscFVDestroy(&fvm); CHKERRQ(ierr);
>> ierr = DMDestroy(&dm);       CHKERRQ(ierr);
>> ierr = PetscFinalize();
>> return ierr;
>> }
> 
> -- 
> 
> 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/ [1]

 

Links:
------
[1] http://www.cse.buffalo.edu/~knepley/
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