[gmx-developers] Problem with qmmm and mpi combo (4.0.5)

Ake Sandgren ake.sandgren at hpc2n.umu.se
Fri Nov 20 17:09:27 CET 2009

On Fri, 2009-11-20 at 16:40 +0100, Ake Sandgren wrote:
> Hi!
> When building gromacs 4.0.5 for qmmm and mpi something goes wrong
> (unless its in the input data of course :-)
> For the input data I'm using (from a user of ours) i have the following
> problem:
> In qmmm.c update_QMMMrec the gmx_sumi in the parallel excecution part
> have inconsistent values in md->nr, i.e. not the same on process 0 and
> process 1. (Causing a problem in the Allreduce)
> Also fr->QMMMlist_sr.nri is different between processes.
> What might be the cause of this? Input data error or bug in the code?
> I've been trying to backtrace this but it's now friday afternoon and i'm
> giving up :-(

It happens in the call to atoms2md since comm->nat[ddnatCON] is

Ake Sandgren, HPC2N, Umea University, S-90187 Umea, Sweden
Internet: ake at hpc2n.umu.se   Phone: +46 90 7866134 Fax: +46 90 7866126
Mobile: +46 70 7716134 WWW: http://www.hpc2n.umu.se

More information about the gromacs.org_gmx-developers mailing list