LAMMPS driver (fix mxl)

Confirm prerequisites

• •Build a LAMMPS binary that includes the MaxwellLink fix.
  • •Preferred: run mxl_install_lammps to build an lmp_mxl binary.

Configure the socket hub

• •Create a TCP or UNIX socket hub on the MaxwellLink (EM) side:
  • •hub = mxl.SocketHub(host="0.0.0.0", port=31415, timeout=60.0)

Configure LAMMPS input

• •Add the fix to the relevant atom group:
  • •fix 1 all mxl <host> <port> [unix] [reset_dipole]

Notes

• •Ensure every atom has a charge; otherwise the coupling force is zero.
• •Use skills/mxl-hpc-slurm/SKILL.md when the hub and LAMMPS run on different nodes.
• •Common SLURM pattern:
  • •Main job writes tcp_host_port_info.txt (host on line 1, port on line 2).
  • •Driver job patches a template input and runs LAMMPS:
    • •cp in_mxl.lmp in.lmp
    • •sed -i -e "s/HOST/$HOST/g" in.lmp && sed -i -e "s/PORT/$PORT/g" in.lmp
    • •srun -n $SLURM_NTASKS lmp_mxl -in in.lmp
• •Read full details in docs/source/drivers/lammps.rst.