Barry : > > 1) One problem is all the parallel MatMatSolve() use the MPIDense > matrices. What is the likelihood that they could be changed to use the > elemental matrices (note that with the MPIDense matrices using the simple > array format the MatMatSolve() codes are very straight ward and do not need > crazy remappings. > > 2) The MPIDense matrices use MatGetArray() all over the place; which > would not work with any non-trivial cyclic storage crap that those guys > love. I may need to write a temporary MatMPIDenseGetArray() until the > MPIDense business can be resolved. > > Do we need to keep MPIDense around and just strip out all of it that > uses plapack? If that is possible? > I prefer this approach, i.e., "just strip out all of it that uses plapack", and keep MPIDense, which is useful as petsc dense multi-vectors, and perhaps other usage.
Hong > > > > > On Aug 13, 2012, at 12:14 PM, Matthew Knepley <knepley at gmail.com> wrote: > > > 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 > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20120813/915e636a/attachment-0001.html>
