[petsc-dev] SNES, Coloring, DM, and TS

[Jed Brown]

On Tue, Feb 28, 2012 at 11:03, Matthew Knepley <knepley at gmail.com> wrote:

> So you think this has nothing to do with
>   - Refinement/coarsening
>   - Local evaluation
>   - Partitioning
> It is all implied, and in fact only really works completely for Cartesian
> stuff.
>

It's not in the DM *interface*. Implementing the interface for an
unstructured grid, etc, will involve *doing* these things, but it doesn't
mean that the logic needs to be in your DM_XXX() or that we need another
public object to share stuff between DMs.


>
>
>>
>>
>>>  - Modeling approximation (like function spaces, projectors)
>>>
>>
>> This is only in the DM interface through coarsening and interpolation.
>>
>
> You also need to know this to piece together local evaluations.
>

*If* that is the interface you want DMXX users to implement to expose their
physics. The concept is not in the DM interface.


>
>
>>
>>
>   - Modeling equations (including decompositions, variable substitutions)
>>>
>>
>> This is only in the DM interface with collective semantics. (For
>> nonlinear ASM, I would be in favor of getting a subdomain DM which would
>> have collective semantics on the subcommunicator instead of putting "local"
>> evaluation into the public interface.)
>>
>
> The equations are there explicitly in all these function pointers it is
> holding. What are you talking about?
>

The local function stuff is in DM_DA, not in DM. The DM interface _only_
exposes collective evaluation.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20120228/3d84db58/attachment.html>