Applications/Mpich
Contents
Application Details
- Description: MPICH is a freely available, portable implementation of MPI, the Standard for message-passing libraries. It implements all versions of the MPI standard including MPI-1, MPI-2, MPI-2.1, MPI-2.2, and MPI-3.
- Version: 3.2 (compiled with gcc or intel)
- Modules: mpich/3.2/gcc-5.2.0 and mpich/intel/3.2.0
- Licence: Open source under Github
Usage Examples
Message Passing Interface (MPI) is a standardized and portable message-passing system designed by a group of researchers from academia and industry to function on a wide variety of parallel computing architectures. The standard defines the syntax and semantics of a core of library routines useful to a wide range of users writing portable message-passing programs in C, C++, and Fortran.
Interactive Mode
The MPI Standard describes mpiexec as a suggested way to run MPI programs. MPICH implements the mpiexec standard, and also provides some extensions. This example runs on a reserved node (eg. c001)
[username@c001 ~]$ module add mpich/3.2/gcc-5.2.0 [username@c001 ~]$ mpiexec -n 28 mpiTEST
This can be run with a host file, the file here is called machinefile:
[username@c001 ~]$ module add mpich/3.2/gcc-5.2.0 [username@c001 ~]$ mpiexec -f machinefile -n 28 mpiTEST
The 'machinefile' is of the form:
c001 c002:2 c003:4 c004:1
- The ':2', ':4', ':1' segments depict the number of processes you want to run on each node.
Non interactive job
This runs on the scheduler SLURM
#!/bin/bash #SBATCH -J MPI-testXX #SBATCH -N 1 #SBATCH --ntasks-per-node 4 #SBATCH -D /home/user1/CODE_SAMPLES/MPICH #SBATCH -o %N.%j.%a.out #SBATCH -e %N.%j.%a.err #SBATCH -p compute #SBATCH --exclusive echo $SLURM_JOB_NODELIST module purge module add gcc/4.9.3 module add mpich/3.2/gcc-5.2.0 export I_MPI_DEBUG=5 export I_MPI_FABRICS=shm:tmi export I_MPI_FALLBACK=no srun -n4 --mpi=pmi2 /home/user1/CODE_SAMPLES/OPENMPI/scatteravg 100
And passing it to SLURM
[username@login01 ~]$ sbatch mpidemo.job Submitted batch job 889552