[petsc-users] DMPlex and Boundary facets

[Karin&NiKo]

Sure, no problem.
Thanks,
Nicolas

Le mer. 19 mai 2021 à 19:47, Matthew Knepley <knepley at gmail.com> a écrit :

> On Wed, May 19, 2021 at 12:46 PM Karin&NiKo <niko.karin at gmail.com> wrote:
>
>> Thanks, I think I understand.
>> So at the moment, the user has to manage the link between the labels of
>> the different strata and the names.
>>
>
> Yes.
>
>
>> I am mainly willing to use DMPlex  for  AMR  and names of groups are
>> essential in our code - reading what Mat says
>> gives me the impression that this is doable.
>>
>
> I think it is. I will be able to do it in the middle of June if you do not
> have something by then. Can you make an issue?
>
>   Thanks,
>
>       Matt
>
>
>> Thanks again,
>> Nicolas
>>
>> Le mer. 19 mai 2021 à 16:02, Matthew Knepley <knepley at gmail.com> a
>> écrit :
>>
>>> On Wed, May 19, 2021 at 9:57 AM Karin&NiKo <niko.karin at gmail.com> wrote:
>>>
>>>> Thank you very much Lawrence.
>>>> Are the names lost or are they saved somewhere ?
>>>> If I do : "./ex2 -filename /tmp/test/Cube_with_facets.msh4 -dm_view
>>>> vtk:/tmp/foo.vtk" , I only get the tets of the initial mesh.
>>>>
>>>
>>> Yes, the names are lost. Jed, Lisandro and Stefano have also asked me
>>> about this. I have not done since everything is currently done by
>>> number in Plex. It would involve either
>>>
>>> a) making a separate table in the DM which translates names to numbers
>>>
>>> or
>>>
>>> b) putting such a translation table in the DMLabel itself
>>>
>>> I am putting it off because doing some short is not hard, but getting it
>>> to work with everything else would be somewhat of a pain.
>>> It would need to distribute properly, propagate to
>>> refined/coarsened/subset meshes, etc. which labels currently do. It would
>>> not
>>> be properly passed on when you just set an int on a point. I think it
>>> will happen eventually, but I don't think I have time in the next
>>> few weeks.
>>>
>>>   Thanks,
>>>
>>>      Matt
>>>
>>>
>>>> Thanks,
>>>> Nicolas
>>>>
>>>> Le mer. 19 mai 2021 à 15:49, Lawrence Mitchell <wence at gmx.li> a écrit :
>>>>
>>>>>
>>>>>
>>>>> > On 19 May 2021, at 14:46, Karin&NiKo <niko.karin at gmail.com> wrote:
>>>>> >
>>>>> > Dear Matthew,
>>>>> >
>>>>> > You are (again) right. This Gmsh test file is "dirty" : some
>>>>> triangles do not belong to tests. Sorry for that.
>>>>> > I have tried with another geo file (which is clean in that sense)
>>>>> and PETSc reads with no error.
>>>>> >
>>>>> > I take this opportunity to ask my initial question : are the labels
>>>>> of the Physical Entities saved somewhere ?
>>>>> > A gmsh test file with several Physical entities is attached to this
>>>>> email.
>>>>>
>>>>> Yes, plex represents Physical entities as "labels". In particular, for
>>>>> facets, they are loaded as the "Face Sets" label, plex also loads markers
>>>>> on cells in the "Cell Sets" label.
>>>>>
>>>>> e.g. here's the DMView output of your mesh.
>>>>>
>>>>> DM Object: DM_0x84000000_0 1 MPI processes
>>>>>   type: plex
>>>>> DM_0x84000000_0 in 3 dimensions:
>>>>>   0-cells: 64
>>>>>   1-cells: 279
>>>>>   2-cells: 378
>>>>>   3-cells: 162
>>>>> Labels:
>>>>>   celltype: 4 strata with value/size (0 (64), 6 (162), 3 (378), 1
>>>>> (279))
>>>>>   depth: 4 strata with value/size (0 (64), 1 (279), 2 (378), 3 (162))
>>>>>   Cell Sets: 1 strata with value/size (7 (162))
>>>>>   Face Sets: 6 strata with value/size (3 (18), 6 (18), 2 (18), 5 (18),
>>>>> 1 (18), 4 (18))
>>>>>
>>>>>
>>>>> Lawrence
>>>>
>>>>
>>>
>>> --
>>> 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/
>>> <http://www.cse.buffalo.edu/~knepley/>
>>>
>>
>
> --
> 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/
> <http://www.cse.buffalo.edu/~knepley/>
>
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