name: mxl-driver-lammps
description: This skill should be used when users want to couple MaxwellLink to LAMMPS via the bundled fix mxl, including build/install and socket connection patterns.

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.