Parallel Computing with Workstation

Hello,
Are you working on a single computer or do you have access to a cluster.
If it is a single computer, you should simply need to the following
mpirun -n 128 liggghts -in in.liggghts
If it is a cluster, the command gets longer...

Running LIGGGHTS on a cluster is not as straight forward and you should contact the cluster admin on how to do it for the cluster.
if you are not using a scheduler, like SLURM (https://slurm.schedmd.com/documentation.html), and simply connected some computers together and are only using the mpi interface then you could try the following.

mpirun --mca plm_rsh_no_tree_spawn 1 --mca btl_tcp_if_include em1 --verbose --show-progress --display-map --display-topo -np 36 -hostfile HOSTFILE liggghts -in in.liggghts -partition 36x1

This is what I used as a proof of concept before we moved to a larger cluster. The above command spawned 36 different simulations at the same time. If you would like to split the domain into 36 pieces, simply omit -partition 36x1
em1 was the internet adapter that all computers used to "talk" to the master node. --mca plm_rsh_no_tree_spawn 1
turns off tree spawning so every machine does NOT need keys to all other machines. With this command, the slave only ever needs the master key.
HOSTFILE is a file that contains the ip address of all the machines used in this cluster
and the thing that took me longer to debug than I would like to admit...