[petsc-users] matsetvaluesblocked4_

[Matthew Knepley]

On Wed, May 27, 2020 at 7:09 PM Mark Adams <mfadams at lbl.gov> wrote:

>
>
>>>
>>> Matt: Could I use BAIJ with Plex?
>>>
>>
>> Plex does this automatically if you have blocks.
>>
>
> I use DMCreateMatrix with forest or plex and I seem to get AIJ matrices.
> Where does Plex get the block size?
>
> I have not yet verified that bs is set in this matrix.
>

I think I may know what your problem is. Plex evaluates the blocksize by
looking for an equal number of dofs
on each point. This is sufficient, but not necessary. If you are using
higher order methods, there is block structure
there that I will not see.

Jed, is there an obvious way to see that structure that I am missing?

  Thanks,

     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

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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