On Sun, Jul 22, 2012 at 1:50 PM, Matthew Knepley <knepley at gmail.com> wrote:
> I think we have to figure out how to do this pipelined thing in a > mechanical way (not necessarily automated, but > done without thinking). You would think this had been figured out by the > architecture guys. > Bah, those guys don't use mathematical invariants so when they see an instruction sequence like a Krylov method, they say there is a data dependency and the pipeline stalls. The pipelined Krylov methods use the structure and the choices you make affect stability. In the case of GMRES, I think we just add an extra VecMDotBegin/End pair in with projection against the prior Krylov space (before normalization). -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20120722/82aa84fe/attachment.html>
