I think this summary is about right. At least I can run something now and have an idea of what it is. I will probably also be transitioning to cp for my runs.
I have been working with the folks at the supercomputing center, and will continue in hopes of finding out what is causing the trouble. Thanks, Dave On Feb 13, 2009, at 3:33 AM, Paolo Giannozzi wrote: > In conclusion, and if I understand correctly: > > PWscf runs only with 1 MPI process per core, but > it runs 800+ atoms in as little as 32 processes > or in as much as 512, as I was expecting. > > This confirms my opinion that the problem is on the > BG side and not on the PWscf side, since there is > NOTHING in the fortran code that depends upon where > the MPI processes are running. Of course one can > never rule out the possibility that some obscure > bug is triggered only in that special cases, but > it seems to me highly unlikely. > > Implementation of mixed MPI-openMPI parallelization > is under development, but it wil take some time. In > the meantime, if you can link openMPI-aware > mathematical libraries, you might get some speedup. > > If you do not need k-points, and if you know how to > deal with metallic systems, you might try CP instead > of PWscf - it is better tested for large systems - but > I don't expect a different behavior, since the routines > performing parallel subspace diagonalization are the > same that perform iterative orthonormalization, so the > trouble is likely to move from "cholesky" to "ortho". > > You might try to find out what is wrong, since you have > two cases that should yield exactly the same results > but don't. It may take a lot of time and lead to no > result, though. You may also try to raise this issue > with the technical staff of the computing center. > > Paolo > -- > Paolo Giannozzi, Democritos and University of Udine, Italy David E. Farrell Post-Doctoral Fellow Department of Materials Science and Engineering Northwestern University email: d-farrell2 at northwestern.edu -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090213/97886a3d/attachment.htm
