[petsc-dev] Stokes and saddle point solvers in PETSc?

[Matthew Knepley]

On Wed, Jun 15, 2011 at 1:47 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
> On Jun 14, 2011, at 8:45 PM, Matthew Knepley wrote:
>
> > On Wed, Jun 15, 2011 at 1:42 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> >
> > On Jun 14, 2011, at 8:36 PM, Matthew Knepley wrote:
> >
> > > On Wed, Jun 15, 2011 at 1:20 AM, Barry Smith <bsmith at mcs.anl.gov>
> wrote:
> > >
> > > On Jun 14, 2011, at 7:59 PM, Jed Brown wrote:
> > >
> > > > On Wed, Jun 15, 2011 at 02:53, Barry Smith <bsmith at mcs.anl.gov>
> wrote:
> > > >  It seems we should provide a DMSDA that is built specifically for
> staggered grids, with the correct number of "slots" in the correct
> "locations", it would have appropriate grid hierarchies and
> interpolation/restriction. Not terribly hard but a bit of basic plumbing
> code. I would rather have this then try to "tack on" the current DA a bunch
> more stuff.
> > > >
> > > > Yeah, though there are many different staggered discretizations so
> this could end up being a big project. Not conceptually hard, just a lot of
> code. DMDA is already not especially small.
> > >
> > >  DMDA started out small. DMSDA will start out small :-)
> > >
> > >  Actually before we do DMSDA we probably should do a code review of DM,
> then of DMDA and slim down DMDA a good amount.
> > >
> > > My vote would be to layer PetscSection on top of DMDA. That would allow
> arbitrarily complex data layout over a dead simple
> > > topology. Its halfway to DMMesh, and it should be the easy half.
> >
> >  It won't give the proper layout of degree's of freedom relative to their
> neighbors of the stagger mesh nor communicate the right ghost points.
> >
> > Why not? I have done it before. The trial implementation (in C++) is in
> src/dm/impls/cartesian. I will just reimplement that completely
> > in C.
>
>    If so, why not dump DMDA also and replace it with a dead simple
> implementation based on PetscSections?


I want to do that, eventually. DMDA is incredibly well tested, and
optimized.

   Matt


>
>   Barry
>
> >
> >   Matt
> >
> >
> >   Barry
> >
> > >
> > >    Matt
> > >
> > >
> > >   Barry
> > >
> > >
> > >
> > >
> > >
> > > --
> > > 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
> >
> >
> >
> >
> > --
> > 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
>
>


-- 
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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20110615/fd965024/attachment.html>