Can you give me a further explanation about why results are different when it ran it on mutiprocessors against single processor?
Thank you! On Fri, Jul 10, 2009 at 4:20 AM, Ashley Pittman<ash...@pittman.co.uk> wrote: > On Thu, 2009-07-09 at 23:40 -0500, Yin Feng wrote: >> I am a beginner in MPI. >> >> I ran an example code using OpenMPI and it seems work. >> And then I tried a parallel example in PETSc tutorials folder (ex5). >> >> mpirun -np 4 ex5 >> It can do but the results are not as accurate as just running ex5. >> Is that thing normal? > > Not as accurate or just different? Different is normal and in light of > that accurate is itself a vague concept. > >> After that, send this job to supercomputer which allocates me 4 nodes >> and each node has 8 processors. When I check load on each node, I >> found: > >> Does anyone have any idea about this? > > I'd say it's obvious all 32 processes have been located on the same > node, what was the mpirun command you issued and the contents of the > machinefile you used? > > Running "orte-ps" on the machine where the mpirun command is running > will tell you the hostname where every rank is running or if you want > more information (load, cpu usage etc) you can use padb, the link for > which is in my signature. > > Ashley, > > -- > > Ashley Pittman, Bath, UK. > > Padb - A parallel job inspection tool for cluster computing > http://padb.pittman.org.uk > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
