[petsc-users] Nodes added to Vertex Set

[Noam T.]

Hello,

In the mesh attached, a 1x1x1 cube with 8 nodes, physical groups are defined for the 6 bounding faces only. According to the GUI, and looking at the MSH file in $Entities, there are no physical groups for nodes.

Using the following code:

---
#include <stdio.h>
#include <petscdmplex.h>

int main(int argc, char *argv[]) {

DM dm;
PetscInt v;

PetscCall(PetscInitialize(&argc, &argv, NULL, NULL));

PetscCall(PetscOptionsInsertString(NULL, " -dm_plex_gmsh_mark_vertices "));
PetscCall(DMPlexCreateFromFile(PETSC_COMM_WORLD, "mesh.msh", "test", PETSC_TRUE, &dm));
PetscCall(DMGetLabelSize(dm, "Vertex Sets", &v));
printf("\nVertex set size %d\n", v);

PetscCall(PetscFinalize());
}
---
it says "Vertex Sets" has size 6, with IS [1, 2, 3, 4, 5, 6]. Is that intended behavior? Up until now I relied on having an empty set whenever physical tags where not explicitly defined, but this one mesh seems to be an exception.

Thanks.

Noam

PS: The size is v = 0 when removing the flag "-dm_plex_gmsh_mark_vertices".
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