[petsc-dev] DMDA_*PERIODIC and DMDA_XYZGHOSTED

[Dmitry Karpeev]

I actually prefer the model where a geometric object (e.g., a DA) controls
the restriction (e.g., DAGlobalToLocalBegin, etc).

On Tue, Dec 7, 2010 at 2:29 PM, Dmitry Karpeyev <dkarpeev at gmail.com> wrote:

> Yes, but how is the local form defined?  Do you suggest that every Vec
> carry a scatter from the global to the local form?
> That appears to be a necessarily geometric (maybe in the abstract sense)
> notion of restricting to some subdomain, which
> might involve degrees of freedom not currently owned locally, and which
> become "ghosts".
>
>
> On Tue, Dec 7, 2010 at 2:24 PM, Jed Brown <jed at 59a2.org> wrote:
>
>> On Tue, Dec 7, 2010 at 21:20, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>
>>> In other words all parallel Vecs could have related local forms and the
>>> model is "give me local form Vec", scatter to/from local form vec etc?
>>
>>
>> The only consequence I can think of is that simultaneously manipulating
>> the global and local forms could not be allowed (in a manageable way).  But
>> I think any need to do that is an obscure edge case.
>>
>> Jed
>>
>
>
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