Without using the flag -dm_plex_gmsh_use_regions, the DMGetNumLabels says there are  5, named celltype, depth, cell/face/vertex sets.

With the flag, the labels are celltype, depth, my_vol, my_surface (using the same example as before).

Am I misusing the flag somehow, and I should be able to access those of cell/face/vertex as well?

PS: Using PETSc 3.20.3

Thanks, 

Noam

On Thursday, January 11th, 2024 at 5:28 PM, Matthew Knepley <knepley@gmail.com> wrote:

On Thu, Jan 11, 2024 at 11:18 AM Noam T. via petsc-users <petsc-users@mcs.anl.gov> wrote:

Would it be feasible to have an option (e.g. new flag along the lines of -dm_plex_gmsh_...) that allows the user to access both the default sets (Cell / Face / Vertex) together with user-defined gorups (those under $PhysicalNames, available when using -dm_plex_gmsh_use_regions)?

I am not sure I understand the question. When you turn on regions, it makes extra labels, but the generic labels still exist.

Thanks,

Matt

That is, with a *.msh file containing

$PhysicalNames

2

2 100 "my_surface"

3 200 "my_vol"

the return of DMGetLabelName(dm, n, name) would be (order may differ)

n = 0, name = "celltype"

n = 1, name = "depth"

n = 2, name = "Cell Sets"

n = 3, name = "my_vol"

n = 4, name = "Face Sets"

n = 5, name = "my_surface"

...

I poked into src/dm/impls/plex/plexgmsh.c and have managed to print all the labels after changing a couple of variable values, so perhaps it is doable.

The changes made are not a solution, simply naively set some variables to skip checking for the use_regions flag, so it understandably crashes soon after.

Thanks, Noam

--

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/