[petsc-dev] FAS with TS

[Matthew Knepley]

On Wed, Feb 8, 2012 at 12:35 AM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> On Wed, Feb 8, 2012 at 08:57, Matthew Knepley <knepley at gmail.com> wrote:
>
>> I just want to point out that Jed envisions that coefficients (and maybe
>> subproblems, etc) cannot be accommodated on the
>> same DM. I agree. However, this silly idea that we can make DMs all over
>> the place with no cost, like DAs, if they contain
>> all the mesh information, is just wrong. I think this is a good argument
>> for having both a topology object and a DM handling
>> layout/solver information. What is the counter-argument?
>>
>
> Why can't we have multiple DMs that internally share topology? Then each
> implementation can share or not share as much as they like. Some DMs might
> also share topological information between levels. I don't think it makes
> sense to encode a specific sharing model into the type system.
>

So you would have some weird call to that DM that says "make another DM and
share the internal state"? That sounds
error prone and hard to inspect from outside. Things we complain about when
other people do them.

   Matt

-- 
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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