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
