On Fri, Dec 23, 2011 at 10:48 AM, Mark F. Adams <mark.adams at columbia.edu>wrote:
> > On Dec 23, 2011, at 10:53 AM, Jed Brown wrote: > > On Fri, Dec 23, 2011 at 09:50, Mark F. Adams <mark.adams at > columbia.edu>wrote: > >> Humm, my G-S in not in PETSc and it is perfectly scalable. It does have >> more complex communication patterns but they are O(1) in latency and >> bandwidth. I'm not sure I understand your description above. > > > It was more like, here's something that perhaps we want to put in PETSc, > what rich communication pattern does it use, such that, if provided, the > implementation would be simple? > > > There is the implementation in Prometheus that uses my C++ linked lists > and hash tables. I would like to implement this with STLs. I also hack > into MPIAIJ matrices to provide a primitive of applying G-S on an index set > of local vertices, required for the algorithm. This should be rethought. > I would guess that it would take about a week or two to move this into > PETSc. > > The complex communication required make this code work much better with > large subdomains, so it is getting less attractive in a flat MPI mode, as > it is currently written. If I do this I would like to think about doing it > in the next programming model of PETSc (pthreads?). Anyway, this would > take enough work that I'd like to think a bit about its design and even the > algorithm in a non flat MPI model. > I think we should give at least some thought to how this would look in Thrust/OpenCL. Matt > Note, I see the win with G-S over Cheby in highly unsymmetric (convection, > hyperbolic) problems where Cheby is not very good. > > Mark > -- 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/20111223/eca66ab9/attachment.html>