On Mon, Nov 11, 2013 at 5:33 AM, Stephan Kramer <[email protected]>wrote:
> On 01/11/13 06:01, Matthew Knepley wrote: > > On Wed, Oct 30, 2013 at 9:19 PM, Rhodri Davies > <[email protected]<mailto: >> [email protected]>> wrote: >> >> Dear all, >> >> Would you mind giving us an update on your thoughts re: this >> question? We're very keen to be able to use such functionally and it would >> be good to know if you're looking into this / have any >> suggestions? >> >> >> I looked at the code. It does not look hard to make a MPIBAIJ version. >> Since the scatter context for BAIJ is already exploded, most >> of the MPIAIJ code goes straight through, it just a matter of handling >> the blocking in a few places. >> >> Here is what would be really helpful for us. Write a nice test. The code >> would probably only take an hour of being careful. However, >> the test assembly would be more. If you give us a nice test example for >> it, writing it could happen pretty quickly. >> >> Thanks, >> >> Matt >> > > That would be great. I had a look at the existing tests and found > src/mat/examples/tests/ex140.c which already claims to test > MatZeroRowsColumns with MPIBAIJ - except it isn't being run in parallel. > Would running this test in parallel be a sufficient test to work with? It > currently fails with the expected message "No support for this operation > for this object type!". I'd be happy to write another test but it would > basically be creating another matrix and testing it does the right thing > with the matrix and the rhs. Let me know if there's anything else we could > help out with > As far as I can tell ex140 does not really work. I am using ex12 to check my rewrite of MatZeroRows(). I would like a companion to that which uses RowsColumns(). And the work here is to provide the output to check against. Even for ex140 I would have to do that, which means more time here. Matt > Cheers > Stephan > > > From: Stephan Kramer <[email protected]> >>> Subject: Fwd: [petsc-users] MatZeroRowsColumns for mpibaij >>> Date: 31 October 2013 13:16:05 GMT+11:00 >>> To: Rhodri Davies <[email protected]> >>> >>> >>> >>> >>> -------- Original Message -------- >>> Subject: [petsc-users] MatZeroRowsColumns for mpibaij >>> Date: Wed, 19 Jun 2013 13:22:31 +0100 >>> From: Stephan Kramer <[email protected]> >>> To: PETSc users list <[email protected]> >>> >>> Dear all, >>> >>> We have found the MatZeroRowsColumns() routine to be very useful for >>> lifting boundary conditions. Unfortunately we also found that it isn't >>> implemented for matrix type mpibaij and we're quite keen on >>> keeping the baij structure as it seems to give us significant savings >>> for DG problems (in particular the blocked sor). I had a quick look at the >>> implementation of MatZeroRowsColums_MPIAIJ but couldn't >>> really estimate how hard it would be to do something similar for mpibaij >>> (an implementation for seqbaij exists already). Is this something that's >>> likely to be looked at in the future? >>> >>> Stephan >>> >> -- 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
