[petsc-users] DMPlex filter with Face Sets

[Thibault Bridel-Bertomeu]

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 ?

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
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