[gmx-users] errors when running gromacs in parallel

[gianluca santarossa]

Dear gmx-users,

I'm learning how to run Gromacs simulations using MPI.
I'm using simple configuration files, only to test parallel simulations.

My computers have 2 Intel(R) Xeon(TM) processors each. I'm using Redhat
7.3 with kernel 2.4.20, and tried both rpm and source  packages of
LAM-MPI, fftw and gromacs. 

Simulations work fine when using 1 or 2 processors, both with one node
or two nodes. But when I use 3 or more processors I encounter some
errors:

MPI_Send: process in local group is dead (rank 1, MPI_COMM_WORLD)
MPI_Wait: process in local group is dead (rank 3, MPI_COMM_WORLD)
Rank (1, MPI_COMM_WORLD): Call stack within LAM:
Rank (1, MPI_COMM_WORLD):  - MPI_Send()
Rank (1, MPI_COMM_WORLD):  - MPI_Sendrecv()
Rank (1, MPI_COMM_WORLD):  - main()
Rank (3, MPI_COMM_WORLD): Call stack within LAM:
Rank (3, MPI_COMM_WORLD):  - MPI_Wait()
Rank (3, MPI_COMM_WORLD):  - MPI_Sendrecv()
Rank (3, MPI_COMM_WORLD):  - main()
-----------------------------------------------------------------------------
One of the processes started by mpirun has exited with a nonzero exit
code.  This typically indicates that the process finished in error.
If your process did not finish in error, be sure to include a "return
0" or "exit(0)" in your C code before exiting the application.
 
PID 16072 failed on node n0 (192.168.1.139) due to signal 11.
-----------------------------------------------------------------------------

In your opinion, what can the cause be?

Any ideas?

Thanks
gianluca santarossa