LAMMPS is a classical molecular dynamics code with a focus on materials modeling. It's an acronym for Large-scale Atomic/Molecular Massively Parallel Simulator. LAMMPS has potentials for solid-state materials (metals, semiconductors) and soft matter (biomolecules, polymers) and coarse-grained or mesoscopic systems.

There were ~405,000 downloads of LAMMPS from Sept 2004 thru mid-year 2021. At that point we migrated our website to https://www.lammps.org and a different server, and stopped logging downloads. LAMMPS molecular dynamics package:

LAMMPS reads commands from standard input, so if all you see is the LAMMPS version number, it is probably waiting for input. You could type in commands but that would be tedious. You need to put commands in a text file or input script like in.lj and run LAMMPS like this:

Axel Kohlmeyer organized a LAMMPS Users and Developers Workshop and Symposium at the International Centre for Theroretical Phyics (ICTP) in Trieste, Italy in March 2014. See details of the program at this link. Steve Plimpton: LAMMPS Overview; Simple LAMMPS Examples; Modeling Thermal Transport and Viscosity with MD; Modifying and Extending LAMMPS

LUNAR stands for LAMMPS Utility (for) Network Analysis (and) Reactivity and is a stand alone Python (3.7+) toolkit to supplement LAMMPS. LUNAR is focused on pre-processing and post-processing inputs and outputs of LAMMPS with emphasis of using LAMMPS for producing structure-property relationships for ICME process modeling of polymers.

The forum replaces the lammps-users mailing list which was discontinued on June 30th, 2022.

Porting LAMMPS to GPUs Still largely a research effort Marc Adams (Nvidia) Pratul Agarwal (ORNL) Sarah Anderson (Cray) Mike Brown (Sandia) Paul Crozier (Sandia) Massimiliano Fatica (Nvidia) Scott Hampton (ORNL) Ricky Kendall (ORNL) Hyesoon Kim (Ga Tech) Axel Kohlmeyer (Temple) Doug Kothe (ORNL) Scott LeGrand (Nvidia) Ben Levine (Temple)

•“On-the-fly” analysis: use LAMMPS to compute/accumulate/average properties of interest while the simulation is running –Use “variable” commands to perform simple calculations –Use “compute” and “fix” commands for more elaborate calculations •Post-processing: use external tools (Python scripts) to

ReaxFF in LAMMPS Command Syntax pair_style reax 10.0 1.0e-5 pair_coeff * * ffield.reax 3 1 2 2 Potential Files ffield.reax.mattsson: general-purpose hydrocarbon parameterization Mattsson et. al, "First-Principles and Classical Molecular Dynamics Simulation of Shocked Polymers,” Phys. Rev. B 81 054103 (2010). ffield.reax.budzien: PETN

The seventh LAMMPS Workshop and Symposium was held virtually on August 10-13, 2021 and was hosted by Temple University. Recorded videos of the presentations and presentation slides (where available) can be accessed by clicking on the talk titles in the schedule below.