On Sat, Jan 28, 2012 at 8:00 AM, Mark F. Adams <mark.adams at columbia.edu>wrote:
> > On Jan 27, 2012, at 8:22 PM, Barry Smith wrote: > > > > > On Jan 27, 2012, at 6:36 PM, Mark F. Adams wrote: > > > >> > >> On Jan 27, 2012, at 6:58 PM, Jed Brown wrote: > >> > >>> On Fri, Jan 27, 2012 at 17:48, Matthew Knepley <knepley at gmail.com> > wrote: > >>> Is now the right time. Shouldn't we wait until MPI's replacement is > working and do things with that model? > >>> > >>> I'm laughing. Am I supposed to be? > >>> > >>> I'm laughing too. > >>> > >>> There isn't going to be a replacement for MPI until the smart people > that understand parallel programming, performance, and libraries start > working on something other than MPI. But most of those people are on the > MPI Forum, trying to improve MPI. Now we need a good model for threads, and > that might not be based on MPI, but it sure looks like the large-scale > distributed-memory model will be MPI for the foreseeable future. > >>> > >> > >> I don't think its a matter of smart people not having worked on this, > they have IMO, its just a hard problem. > > > > I disagree; it is not necessarily hard, it is just that the non-MPI > people are pretty fucking stupid. > > > > It is not hard, intellectually intriguing, fundable, and smart people > won't do it. What am I missing? I think Barry's point is that this is another case where, no matter how smart or motivated you are, if you start out with a bad design decision in the beginning, and refuse to change it for whatever reason, you will not succeed. Matt > > Barry > > > >> > >>> > >>> As for sources of parallel errors, yes, it's somewhat tricky, but as > long as the model is to get a sub-object out of a bigger one (submatrix, > coarse level, etc), I think we can manage it. At any particular time, the > user should still be looking at essentially single-comm collections of > objects, but not all processes will end up being called in every context. > >> > > > > > > -- 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/20120128/f9511511/attachment.html>
