LAMMPS simulator

A light-weight Python package for launching LAMMPS simulations. Given a LAMMPS input script, the simulation is launched from a specified working directory. The default behavior is to copy the input script and all dependencies to the working directory, making it easy to redo the simulations.

Installation

Install package from source using pip:

$ pip install git+https://github.com/evenmn/lammps-simulator

Prerequisites

1. Python 3.3+ (subprocess.DEVNULL from 3.3 needed)
2. LAMMPS (Any recent version)

Basic usage

The code is oriented around the Simulator class, which takes the working directory as argument. Below follows a simple usage example:

from lammps_simulator import Simulator
from lammps_simulator.computer import CPU

sim = Simulator(directory="simulation")
sim.set_input_script("script.in")
sim.run(computer=CPU(num_procs=4, lmp_exec="lmp_mpi"))

where the LAMMPS input script script.in is launched from the directory simulation on 4 CPU processes by calling the LAMMPS executable lmp_mpi.

Copy to working directory

Often, the LAMMPS script requires other files, like parameter files, data files or other LAMMPS scripts. The function copy_to_wd can be used to copy any file to the working directory:

sim.copy_to_wd("parameters.vashishta")
sim.copy_to_wd("pos.data")
sim.copy_to_wd("compute_something.in")

or more compact:

sim.copy_to_wd("parameters.vashishta", "pos.data", "compute_something.in")

Assign variables to LAMMPS script

If your LAMMPS script takes command line variables, they can be specified by

sim.set_input_script("script.in", var1=v1, var2=v2, ..., varN=vN)

or

lmp_vars = {'var1': v1, 'var2': v2, ... 'varN': vN}
sim.set_input_script("script.in", **lmp_vars)

Variables might also be lists (index variables in LAMMPS terms).

sim.set_input_script("script.in", var=[1, 2, 3])

For more examples, see the examples pages and the documentation.