[petsc-users] DMLocalToLocal with DMPlex in Fortran

[Mike Michell]

Hi, I was wondering if there is any comment on the example file that I can
refer to.

Thanks,
Mike


> Thank you for the reply.
> Sure, a short example code is attached here with a square box mesh and a
> run script.
> Inside the source, you may find two versions of halo exchange; one is for
> local to global (Version-1) and another one is for local to local
> (Version-2), which is not working in my case.
> In the output.vtu, you will see the halo exchanged vector resolved to each
> vertex with (myrank + 1), so if the code is running with 2procs, at the
> parallel boundary, you will see 3. In this example, there is no ghost layer.
>
> Thanks,
> Mike
>
>
>> On Sat, Oct 1, 2022 at 8:51 PM Mike Michell <mi.mike1021 at gmail.com>
>> wrote:
>>
>>> Thank you for the reply. There is that file in
>>> src/dm/interface/ftn-auto/ for me, instead of the path you mentioned.
>>>
>>> After "make allfortranstubs" was done and, PETSc reconfigured and
>>> reinstalled.
>>>
>>> However, I still have the same problem at the line in which
>>> DMLocalToLocalBegin() is used. What I am doing to setup halo exchange is as
>>> follows;
>>> - declare DMPlex
>>> - PetscSectionCreate()
>>> - PetscSectionSetNumFields()
>>> - PetscSectionSetFieldComponents()
>>> - PetscSectionSetChart()
>>> - do loop over dofs: PetscSectionSetDof() and PetscSectionSetFieldDof()
>>> - PetscSectionSetUp()
>>> - DMSetLocalSection()
>>> - PetscSectionDestroy()
>>> - DMGetSectionSF()
>>> - PetscSFSetUp()
>>>
>>> Then, the halo exchange is performed as follows;
>>> - DMGetLocalVector()
>>> - Fill the local vector
>>> - DMLocalToLocalBegin() --(*)
>>> - DMLocalToLocalEnd()
>>> - DMRestoreLocalVector()
>>>
>>> Then, the code crashes at (*).
>>>
>>
>> Can you send something I can run? Then I will find the problem and fix it.
>>
>>   Thanks,
>>
>>      Matt
>>
>>
>>> Previously(at the time PETSc did not support LocalToLocal for DMPlex in
>>> Fortran), the part above, "DMLocalToLocalBegin() and DMLocalToLocalEnd()",
>>> consisted of;
>>> - DMLocalToGlobalBegin()
>>> - DMLocalToGlobalEnd()
>>> - DMGlobalToLocalBegin()
>>> - DMGlobalToLocalEnd()
>>> and it worked okay.
>>>
>>> I am unclear which part is causing the problem. Shall I define the
>>> PetscSection and PetscSF in different ways in case of Local to Local Halo
>>> exchange?
>>> Any comment will be appreciated.
>>>
>>> Thanks,
>>> Mike
>>>
>>>
>>>
>>>> On Fri, Sep 30, 2022 at 4:14 PM Mike Michell <mi.mike1021 at gmail.com>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> As a follow-up to this email thread,
>>>>> https://www.mail-archive.com/petsc-users@mcs.anl.gov/msg44070.html
>>>>>
>>>>> Are DMLocalToLocalBegin() and DMLocalToLocalEnd() really available for
>>>>> DMPlex with Fortran on the latest version of PETSc (3.17.99 from GitLab)?
>>>>> Matt commented that the Fortran bindings were updated so that those
>>>>> functions must be available in the latest version of PETSc, however, it
>>>>> seems still they are not working from my test with DMPlex in Fortran. Can
>>>>> anyone provide some comments? Probably I am missing some mandatory header
>>>>> file? Currently, I have headers;
>>>>>
>>>>> #include "petsc/finclude/petscvec.h"
>>>>> #include "petsc/finclude/petscdmplex.h"
>>>>> #include "petsc/finclude/petscdmlabel.h"
>>>>> #include "petsc/finclude/petscdm.h"
>>>>>
>>>>
>>>> The source for these functions is in
>>>>
>>>>   src/dm/ftn-auto/dmf.c
>>>>
>>>> Is it there for you? If not, you can run
>>>>
>>>>   make allfortranstubs
>>>>
>>>> Fortran functions are not declared, so the header should not matter for
>>>> compilation, just the libraries for linking.
>>>>
>>>>   Thanks,
>>>>
>>>>      Matt
>>>>
>>>>
>>>>> Thanks,
>>>>> Mike
>>>>>
>>>>
>>>>
>>>> --
>>>> 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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