[petsc-users] question about MatMatMultTranspose

[Jack Poulson]

On Thu, Apr 5, 2012 at 10:19 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
> On Apr 5, 2012, at 9:54 AM, Jack Poulson wrote:
>
> > On Thu, Apr 5, 2012 at 9:20 AM, Jack Poulson <jack.poulson at gmail.com>
> wrote:
> > On Thu, Apr 5, 2012 at 8:02 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> >
> >     Parallel dense we know very little about and cannot write those
> routines, sadly there are no decently supported parallel dense matrix
> general purpose libraries out there that we can use (and no Scalapack,
> plapack and elemental do not count as decent AND supported) so it is
> unlikely WE will write the MPIDENSE versions of these routines. Though if
> someone else writes them we would be happy to include them. So basically
> for parallel dense I have no suggestions.
> >
> >
> > If you let me know what your major complaints are, I'll look into them.
> >
> > Jack
> >
> > Forwarding to Jed and Matt; seriously, let me know what your complaints
> are. If I can, I will fix them.
> >
> > Jack
>
>    Jack,
>
>     I apologize, I was too quick to dismiss elemental. We went to the
> effort to do the MPIDENSE interface for PLAPACK and that ended up being a
> complete waste and left a bad taste in my mouth since I consider that
> wasted time when we could have done something else.
>
>
No offense taken; it is understandable that PLAPACK did not meet PETSc's
rigorous development standards, as it was closer to a research code. With
that said, the reason I wrote Elemental is that I wanted a robust linear
algebra package that made use of PLAPACK's insights (ala exposing matrix
distributions as objects).

Given that you had a bad experience with PLAPACK, perhaps the best
assurance I can give you is that I am actively dogfooding Elemental in my
other projects (see http://bitbucket.org/poulson/clique and
http://bitbucket.org/poulson/psp). In addition, van de Geijn has a student
working on extending Elemental's matrix-matrix multiplication code to more
sophisticated distribution schemes. I _highly_ doubt that you will find a
bug in Elemental's matrix-matrix multiplication, but, if you do, I can
assure you that I will fix it within a few hours. The code is quite simple:
http://code.google.com/p/elemental/source/browse/#hg%2Finclude%2Felemental%2Fbasic%2Flevel3%2FGemm


>    So we could try again with Elemental but its a question of having a
> competent person to do the interface efficiently. Perhaps you have a
> student or someone you know that knows elemental we could hire for a short
> time to do an interface and see how it goes?
>
>
Unfortunately I am still just a lowly Ph.D. student (but hopefully that
will change in December). I would be happy to try to help, and _may_ find
the time to write the interface myself, but, until graduation, I can't
promise more than maintenance. I can talk with a few folks that might be
interested, but I would think that this should only take a few days of
work, not anything that warranted an appointment.

Jack
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