[petsc-users] matsetvaluesblocked4_

[Mark Adams]

 I have DM_BOUNDARY_NONE.

On Wed, May 27, 2020 at 7:22 PM Jed Brown <jed at jedbrown.org> wrote:

> Matthew Knepley <knepley at gmail.com> writes:
>
> > 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?
>
> gcd of all the point sizes.
>
> Note that you don't have constant block sizes if you eliminate some
> fields/components in boundary conditions.
>
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