[petsc-users] DMPlex filter with Face Sets

[Matthew Knepley]

On Fri, Jan 14, 2022 at 8:23 AM Thibault Bridel-Bertomeu <
thibault.bridelbertomeu at gmail.com> wrote:

> Dear all,
>
> I have a new question - in relation with my other ongoing thread
> "Fluid-Structure interaction with multiple DMPlex" actually.
> Is it possible to filter a DMPlex and keep in the new piece of DM the
> strata from the Face Sets label that belong to that piece ?
>

You are right. We are not doing labels. That is just an oversight. I will
fix it.

  Thanks,

     Matt


> Consider for instance the following example :
>
> // Standard includes
> #include <cstdlib>
>
> // PETSc includes
> #include <petscsys.h>
> #include <petscdmplex.h>
> #include <petscds.h>
>
> int main(
> int argc, /**< Number of CLI arguments */
> char* argv[] /**< List of CLI arguments as strings */
> )
> {
> User user;
> DM dm;
> PetscErrorCode ierr = EXIT_SUCCESS;
>
> // Start-up the PETSc interface
> ierr = PetscInitialize(&argc, &argv, (char*)0, NULL);if (ierr) return
> ierr;
>
> // Allocate whatever needs to be
> ierr = PetscNew(&user);CHKERRQ(ierr);
>
> // Parse the mesh given by the user
> //+ Mesh filename
> ierr = PetscOptionsBegin(PETSC_COMM_WORLD, NULL, "PETSc DMPlex Coupled
> Physics Demo Mesh Options", "");CHKERRQ(ierr);
> {
> ierr = PetscStrcpy(user->meshName,
> "data/divided_square/divided_square_gmsh22ascii.msh");CHKERRQ(ierr);
> ierr = PetscOptionsString("-meshname", "Mesh filename", "",
> user->meshName, user->meshName, sizeof(user->meshName), NULL);CHKERRQ
> (ierr);
> }
> ierr = PetscOptionsEnd();CHKERRQ(ierr);
> //+ Read the mesh in
> ierr = DMPlexCreateFromFile(PETSC_COMM_WORLD, user->meshName,
> "CoupledPhysics_Plex", PETSC_TRUE, &dm);CHKERRQ(ierr);
> ierr = DMSetFromOptions(dm);CHKERRQ(ierr);
> ierr = DMViewFromOptions(dm, NULL, "-dm_view");CHKERRQ(ierr);
>
> // Extract both domains separately
> //+ Label of the fluid domain
> DMLabel fluidLabel;
> ierr = DMGetLabel(dm, "Fluid", &fluidLabel);CHKERRQ(ierr);
> //+ Sub-DM for the fluid domain
> DM fluidDM;
> // ierr = DMPlexFilter(dm, domainsLabel, 2, &fluidDM);CHKERRQ(ierr);
> ierr = DMPlexFilter(dm, fluidLabel, 2, &fluidDM);CHKERRQ(ierr);
> ierr = DMViewFromOptions(fluidDM, NULL, "-fluid_dm_view");CHKERRQ(ierr);
> //+ Label of the solid domain
> DMLabel solidLabel;
> ierr = DMGetLabel(dm, "Solid", &solidLabel);CHKERRQ(ierr);
> //+ Sub-DM for the solid domain
> DM solidDM;
> ierr = DMPlexFilter(dm, solidLabel, 1, &solidDM);CHKERRQ(ierr);
> ierr = DMViewFromOptions(solidDM, NULL, "-solid_dm_view");CHKERRQ(ierr);
>
> // Close the PETSc interface and end the parallel communicator
> ierr = PetscFree(user);CHKERRQ(ierr);
> ierr = PetscFinalize();
> return(ierr);
> }
>
> run with the mesh attached to this email and the command ./program
> -meshname divided_square_gmsh41ascii.msh -dm_plex_gmsh_use_regions -dm_view
> -fluid_dm_view.
> It yields :
>
> DM Object: CoupledPhysics_Plex 1 MPI processes
>   type: plex
> CoupledPhysics_Plex in 2 dimensions:
>   Number of 0-cells per rank: 1409
>   Number of 1-cells per rank: 4084
>   Number of 2-cells per rank: 2676
> Labels:
>   celltype: 3 strata with value/size (0 (1409), 3 (2676), 1 (4084))
>   depth: 3 strata with value/size (0 (1409), 1 (4084), 2 (2676))
>   Cell Sets: 2 strata with value/size (1 (924), 2 (1752))
>   Solid: 1 strata with value/size (1 (924))
>   Fluid: 1 strata with value/size (2 (1752))
>   Face Sets: 5 strata with value/size (4 (60), 3 (40), 7 (20), 5 (40), 6
> (20))
>   Insulation: 1 strata with value/size (4 (60))
>   Wall: 1 strata with value/size (3 (40))
>   Outlet: 1 strata with value/size (7 (20))
>   Freestream: 1 strata with value/size (5 (40))
>   Inlet: 1 strata with value/size (6 (20))
>
> DM Object: 1 MPI processes
>   type: plex
> DM_0x557ff009be70_1 in 2 dimensions:
>   Number of 0-cells per rank: 937
>   Number of 1-cells per rank: 2688
>   Number of 2-cells per rank: 1752
> Labels:
>   celltype: 3 strata with value/size (0 (937), 1 (2688), 3 (1752))
>   depth: 3 strata with value/size (0 (937), 1 (2688), 2 (1752))
>
> In the attached mesh, Wall, Outlet, Freestream and Inlet "belong" to the
> Fluid domain, therefore I would like to transfer them to the fluidDM during
> or right after the DMPlexFilter action.
> Is that possible ? I was looking at extracting the IS from those labels of
> dm and creating new labels in fluidDM from those IS, but the indices won't
> match, will they ? The filtering operation renumbers everything right ?
>
> Thank you very much !!
>
> Thibault Bridel-Bertomeu
> —
> Eng, MSc, PhD
> Research Engineer
> CEA/CESTA
> 33114 LE BARP
> Tel.: (+33)557046924
> Mob.: (+33)611025322
> Mail: thibault.bridelbertomeu at gmail.com
>


-- 
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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