2012/5/11 Jed Brown <jedbrown at mcs.anl.gov> > I don't like this idea of the matrix type determining the algorithm, I'd > rather choose the algorithm. >
This is note the case in my BDDC: it is the algorithm that drives the type of matrix to be built. > Can we decouple it by building the prolongation operator P whose columns > are harmonic extension of the coarse nodes? Then the coarse operator looks > like P^T A P just like multigrid (for which we have a matop) instead of > looking like a Schur complement. > I already have it. Each process has its local part, splitted in the matrices pcbddc->coarse_phi_B (local interface nodes) and (optionally) pcbddc->coarse_phi_D (local dirichlet nodes). You can see that I used them to check the correctness of the coarse local part in the code (see line 1702 of bddc.c). I build the local part of coarse matrix , but I don't use the expensive PtAP operation. Instead, I evaluate it by exploiting properties of the saddle point problem they come from. > On May 10, 2012 2:42 PM, "Stefano Zampini" <stefano.zampini at gmail.com> > wrote: > >> >> This is to do recursive BDDC or what? >>> >>> >> Yes. When creating the BDDC coarse matrix, now the code has three 3 >> options >> >> A) coarse matrix is a MATIS -> multilevel BDDC >> B) coarse matrix is SEQAIJ -> one level BDDC with only one proc (or all) >> solving directly the coarse problem >> C) coarse matrix is MPIAIJ -> one level BDDC with a parallel direct >> solve >> >> I think that PCREDUNDANT can do the job in both cases of options B if the >> matrix would be parallel. >> > -- Stefano -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20120511/3b5bf939/attachment.html>
