On May 15, 2012, at 6:20 PM, Jed Brown wrote: > On Tue, May 15, 2012 at 10:11 AM, Hui Zhang <mike.hui.zhang at hotmail.com> > wrote: > Yes, see Mandel & Dorhamann' paper http://ccm.ucdenver.edu/reports/rep194.pdf > , > > BDDC needs to solve pinned Neumann problems to build the coarse space. There > is no way to obtain those Neumann problems from an assembled matrix, and > neither PCASM or PCGASM is set up to handle that. > > There is a BDDC implementation from Stefano Zampini in petsc-dev, but the > code is still not mature so you have to configure --with-pcbddc to activate > it.
Yes, thanks! > > but this is for non-overlapping. For overlapping we can see Leong & Widlund > http://cs.nyu.edu/web/Research/TechReports/TR2008-914/TR2008-914.pdf > > This solves non-overlapping Dirichlet problems to construct the coarse basis, > then uses overlapping Dirichlet problems for the smoother. Again, these > problems are different, so it's not useful to extract the subdomain problems > from PC(G)ASM. Yes, but I want to modify it a bit to just use the overlapping subdomains for coarse basis. I think my choice is more natural because we avoid factorization on the non-overlapping subdomains. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120515/c585f2b9/attachment.htm>
