[petsc-dev] why does MatCreate_MPIDense still exist?

[Matthew Knepley]

On Mon, Aug 13, 2012 at 12:07 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
> On Aug 13, 2012, at 12:05 PM, Hong Zhang <hzhang at mcs.anl.gov> wrote:
>
> > Barry,
> > Elemental interface is not well tested yet.
> > I would wait for few months to remove PLAPACK stuff.
>
>     PLAPACK stuff is (and never was) well tested. Does anyone rely on it?
> I hope not. And I hate to have someone new come along and rely on it.


I am for removing it. I wrote it, and so I can guarantee that it is not
maintained. We should
just fix anything that comes up rather than fooling ourselves that this
current stuff works.

   Matt


>
>     Barry
>
> >
> > Hong
> >
> > On Mon, Aug 13, 2012 at 11:50 AM, Jed Brown <jedbrown at mcs.anl.gov>
> wrote:
> > On Mon, Aug 13, 2012 at 10:40 AM, Barry Smith <bsmith at mcs.anl.gov>
> wrote:
> > Should I remove all the MPIDense stuff from PETSc now?   It is uses
> PLAPACK which is buggy and unsupported.
> >
> > That is still a good distribution for MxN matrices with M>>N. We can do
> them with Elemental, but that would use a different distribution so it will
> be more complicated to interact with. (The current Elemental interface uses
> a squarish distribution, but we can tell Elemental to use the [VC,*]
> distribution (for which fewer operations are supported).
> >
> > The main thing I care about for that distribution is QR. The best format
> is dense and row-aligned. I don't care whether it uses MPIDense or a new
> "multi-vector" thing, but that concept should be somewhere.
> >
>
>


-- 
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
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