[petsc-users] DMLabelFilter start index 0 question

[Emiel van de Ven]

Dear PETSc users,

I have a mesh where I have a label that contains some elements. If I
understand correctly, after uniform refinement, the label also contains the
refined faces and vertices. Since I'd like to have only cells in the label,
I thought to remove the rest using something like:

DMPlexGetDepthStratum(dm, 3, &vStart, &vEnd);
DMLabelFilter(label, vStart, vEnd);

However, I don't fully understand the functioning of DMLabelFilter. When
vStart>0, it works as I would expect, but when vStart=0, it simply removes
all the points from the label. Why is this happening?

Since for the cells vStart usually is 0, I can't use this method. Am I
missing something?

Attached is a minimal working example.

Best,
Emiel
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