[petsc-users] DMPlex shared node indexing

[袁煕]

Thanks, I'll check it out.

Yuan

2021年11月28日(日) 1:17 Barry Smith <bsmith at petsc.dev>:

>
>
> https://gitlab.com/petsc/petsc/-/merge_requests/4542/diffs?commit_id=252cf7895bb78ed4e3a2388b4d15d1e7905925a9
>
> If you use the option -dm_plex_use_vec_ghost_permutation then ghost
> values will be put at the end of the local vector. Note this is work in
> progress so will have rough edges.
>
>
> On Nov 27, 2021, at 10:54 AM, 袁煕 <yuanxi at advancesoft.jp> wrote:
>
> Great! It is of much help to me. But I am not sure how to use it.  Does it
> mean   ghost vertices are put at the end of the local vector  automatically
> after calling DMPlexDistribute? Or additional function calling or setting
> is needed?
>
> Yuan
>
> 2021年11月27日(土) 0:34 Barry Smith <bsmith at petsc.dev>:
>
>>
>>    Actually, with DMPLEX the ghost vertices are not at the end of the
>> local vector, they can be anywhere within the list.
>>
>>    But I have a work-in-progress branch
>> https://gitlab.com/petsc/petsc/-/merge_requests/4542 that labels the
>> ghost locations and moves them to the end. You are welcome to try it.
>>
>>   Barry
>>
>>
>> On Nov 26, 2021, at 8:16 AM, Mark Adams <mfadams at lbl.gov> wrote:
>>
>> First, ghost vertices only show up in "local" (vs "global") vectors and
>> the ghost values are ordered after the locally owned ones.
>> Others might have more to add.
>> Mark
>>
>>
>> On Fri, Nov 26, 2021 at 12:49 AM 袁煕 <yuanxi at advancesoft.jp> wrote:
>>
>>> Dear PETSc-team,
>>>
>>> When the mesh is distributed, the vertices are renumbered and some
>>> vertices are shared by neighboring CPUs. My question is:
>>>
>>> 1. How to check which vertice is a ghost one?
>>> 2. Are those ghost vertices always at the end of vertices list? If not
>>> 3. Are there simple ways to let those ghost vertices come after
>>> owned ones?
>>>
>>> Many thanks
>>>
>>> Yuan
>>>
>>
>>
>
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