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Use the module name lammps to discover versions available and to load the application.

Multicore

Lammps The lmp command can be used across multiple nodes (mpi) and cores (openmp). In general you can simply use the srun command. There is some variation on how to execute this depending on the version being usedan early version on Teton that requires mpirun - see the table below.

General Rules

• You have to request, allocate, and match the number of MPI slots for LAMMPS.

• Use the three parameters: nodes, ntasks-per-node, and cpus-per-task:

  • nodes x ntasks-per-node defines the number of slots.

  • cpus-per-task defines the number of OpenMP threads.

• By default, only one OpenMP thread is used. If you wish to increase this you must define and set the OMP_NUM_THREADS environment variable.

  • Use: export OMP_NUM_THREADS=$SLURM_CPUS_PER_TASK

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Use srun to call the lmp command

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srun lmp -in SC.in

#SBATCH --nodes=1
#SBATCH --ntasks-per-node=16
mpirun -np 16 lmp -in SC.in

#SBATCH --nodes=2
#SBATCH --ntasks-per-node=32
mpirun -np 64 lmp -in SC.in

#SBATCH --nodes=4
#SBATCH --ntasks-per-node=16
#SBATCH --cpus-per-task=2
export OMP_NUM_THREADS=2
TOTAL_NP=$(($SLURM_JOB_NUM_NODES*$SLURM_CPUS_ON_NODE/$SLURM_CPUS_PER_TASK))
mpirun -np $TOTAL_NP lmp -in SC.in

Using Version 20201001 with REPLICA Package

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#SBATCH --nodes=4 / #SBATCH --ntasks-per-node=1

#SBATCH --nodes=2 / #SBATCH --ntasks-per-node=2

#SBATCH --nodes=1 / #SBATCH --ntasks-per-node=4

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