[lammps-users] compute in a multi-core enviroment

Dear Steve and Axel,

Thanks for the information. However, I found out the multi-core is not working.

I’m using a rock cluster, which consist of 18 nodes with 4 cores per node. I had installed mpich2 and g++(LAMMPS).
When I try to run LAMMPS with mpich2 with the following command, say
mpirun -np 8 lmp_g++ < in.file
it automatically uses 8 nodes with 1 core per node, instead of using 2 nodes with 4 cores per node. The frontal is not efficient.

I’m wondering whether I did not configure LAMMPS properly.

Thank you.


That's an MPI and mpirun issue, not a LAMMPS issue.
The MPI installation is responsible for giving physical
procs to LAMMPS (or any other MPI code). LAMMPS
has no knowledge of which physical procs it is running on.