[petsc-users] Multi-domain meshes with DMPLEX

Mon Feb 27 00:29:43 CST 2017

Dear Matt,

Thanks for your reply and help. I replaced the code with DMViewFromOptions() as you suggested. Attached you find the code for your reference, and the output of -dm_view ::ascii_info_detail.

a) -dm_view of the original mesh

DM Object: 1 MPI processes

  type: plex

DM_0x84000000_0 in 3 dimensions:

  0-cells: 16

  1-cells: 61

  2-cells: 80

  3-cells: 34

Labels:

  Cell Sets: 2 strata of sizes (17, 17)

  Face Sets: 3 strata of sizes (12, 8, 10)

  depth: 4 strata of sizes (16, 61, 80, 34)

b) -dm_view of the sub-mesh 45 obtained by DMPlexFilter

 sub-mesh 45

DM Object: 1 MPI processes

  type: plex

DM_0x84000000_1 in 3 dimensions:

  0-cells: 12

  1-cells: 38

  2-cells: 44

  3-cells: 17

Labels:

  depth: 4 strata of sizes (12, 38, 44, 17)

c) -dm_view of the sub-mesh 43 obtained by DMPlexFilter:

 sub-mesh 43

DM Object: 1 MPI processes

  type: plex

DM_0x84000000_2 in 3 dimensions:

  0-cells: 12

  1-cells: 38

  2-cells: 44

  3-cells: 17

Labels:

  depth: 4 strata of sizes (12, 38, 44, 17)

d) -dm_view of the "sub-mesh 40" (interface between sub-meshes 43 and 45) obtained by DMPlexCreateSubMesh:

 interface 40

DM Object: 1 MPI processes

  type: plex

DM_0x84000000_3 in 2 dimensions:

  0-cells: 0

  1-cells: 0

  2-cells: 0 (-83895904)

Labels:

  depth: 0 strata of sizes ()

Questions:

1) the output of (d) is empty. What am I missing?

2) I used the "Cell Sets" DMLabel along with value=45 or 43 to yield the output of (b) and (c), respectively, and they do not contain "Face Sets". Is it expected?

I will address the other question in a separate e-mail, because it is not related to the issues I described above. My apologies the confusion.

Regards,
 Frederico.

________________________________
From: Matthew Knepley [knepley at gmail.com]
Sent: 26 February 2017 23:26
To: Santos Teixeira Frederico
Cc: petsc-users at mcs.anl.gov
Subject: Re: [petsc-users] Multi-domain meshes with DMPLEX

On Sun, Feb 26, 2017 at 10:51 AM, Santos Teixeira Frederico <fsantost at student.ethz.ch<mailto:fsantost at student.ethz.ch>> wrote:
Hi folks,

Attached you find small.msh, a mesh with two prisms (physical domains 43 and  45) and the interface between them (physical domain 40).
test_dmplex.cpp loads the mesh and tries to filter each sub-mesh and the interface. I use PETSc master.

When I load small.msh, all physical domains are correctly assigned to "Cell Sets" or "Face Sets".

1) Both sub-meshes (prisms with domains 43 and 45) are filtered with DMPlexFilter and saved correctly, but the interface isn't. What am I missing?

What exactly does "the interface isn't" mean? Does it mean you are not getting what you expect from the submesh?

One way to more easily communicate about this is to replace your blocks of Viewer commands with one line
DMViewFromOptions() calls. That way you can show me just -dm_view or -dm_view ::ascii_info_detail, or output
VTK with -dm_view vtk:mesh.vtu, or HDF5 -dm_view hdf5:mesh.h5, etc.

We could start off with sending me just the plain ASCII output for the mesh and submeshes. I do recognize you sent
the code, but I have a conference deadline for Monday (I will be there until Friday), so I am unlikely to build it before them.

2) I can retrieve any specific strata of "Cell Sets" with DMPlexFilter, but this operation does not include any related strata of "Face Sets", as pointed by DMView. How can I do it?

Do DMFilter is not propagating labels? Okay, that can go on the bug list. Is this what you mean?

3) Physical domains 43 and 45 could be interpreted as fluid and solid domains in a F.S.I. simulation, for example, and I would like to define fluid and solid sub-problems only on the respective sub-mesh. Do I really need to have fully operational sub-DMPLEX's in order to achieve it? Is there an easier way?

I am not sure I understand what is going wrong yet.

  Thanks,

    Matt

My apologies if the explanations are confusing!

Best regards,
 Frederico.

--
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
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