hover to animate -- input script physical analog (start at 3:25) & explanation

LAMMPS is a classical molecular dynamics code, and an acronym for Large-scale Atomic/Molecular Massively Parallel Simulator.

LAMMPS has potentials for soft materials (biomolecules, polymers) and solid-state materials (metals, semiconductors) and coarse-grained or mesoscopic systems. It can be used to model atoms or, more generically, as a parallel particle simulator at the atomic, meso, or continuum scale.

LAMMPS runs on single processors or in parallel using message-passing techniques and a spatial-decomposition of the simulation domain. The code is designed to be easy to modify or extend with new functionality.

LAMMPS is distributed as an open source code under the terms of the GPL. The current version can be downloaded here. Links are also included to older F90/F77 versions. Periodic releases are also available on SourceForge.

LAMMPS is distributed by Sandia National Laboratories, a US Department of Energy laboratory. The main authors of LAMMPS are listed on this page along with contact info and other contributors. Funding for LAMMPS development has come primarily from DOE (OASCR, OBER, ASCI, LDRD, Genomes-to-Life) and is acknowledged here.

The LAMMPS WWW site is hosted by Sandia, which has this Privacy and Security statement.

• (2/12) Added per-atom energy and virial tallying to the long-range PPPM and Ewald solvers used via the kspace_style command.
• (1/12) Added a pair_style kim to support use of potentials archived by the Knowlegebase of Interatomic Models (KIM) project.
• (12/11) Significant features added to LAMMPS in the fourth quarter of 2011 include per-atom energy/stress with pair style reax/c, USER-OMP package, atom_style line and tri for aspherical particles, pair_style line/lj and tri/lj, FLD package for Fast Lubrication Dynamics, pair_style gauss/cut, pair_style coul/diel, OpenCL support in the GPU package, run_style verlet/split, partition command, processors part, grid, numa options, pair_style coul/wolf, and pair_style born/coul/wolf. See authors here and details here
• (12/11) Added a run_style verlet/split command to allow a simulation with long-range Coulombics (PPPM) to be split across 2 partitions of processors to boost performance when the FFTs in PPPM become a bottleneck on large numbers of processors.
• (10/11) Added a Fast Lubrication Dynamics package (FLD, fast form of Stokesian Dynamics), which can be run in explicit or implicit mode. This is due to contributions from Amit Kumar and Michael Bybee from Jonathan Higdon's group at UIUC. See the new pair_style lubricateU command for more details.
• (10/11) Added line segment and triangular particle types, so that faceted rigid bodies can be modeled in 2d and 3d. See the new pair_style tri/lj command for more details.
• (10/11) Release of the USER-OMP package which provides OpenMP accelerated versions of nearly all pair styles and dihedral styles, as well as some fixes, to enable running in multi-threaded, shared-memory mode on the cores of a multicore processor. See this section of the manual for details.
• (9/11) Significant features added to LAMMPS in the third quarter of 2011 include broader 3rd-party FFT support including KISSFFT as a native LAMMPS FFT, single-precision FFTs for PPPM, fix addtorque, compute temp/rotate, bond_style harmonic/shift and harmonic/shift/cut, angle_style cosine/shift and cosine/shift/exp, dihedral_style cosine/shift/exp, pair_style lj/sf, USER-CUDA package, package command, doc/Developer.pdf, fix restrain, fix gcmc, USER-SPH package, pair_style lj/cubic, fix nphug, and pair_style edip. See authors here and details here
• (8/11) Release of the USER-SPH package which implements smoothed particle hydrodynamics (SPH) in LAMMPS. See these movies and this user's guide for more details.
• (8/11) Release of the USER-CUDA package which provides accelerated versions for NVIDIA GPUs of 28 pair styles, 14 fixes, and 4 computes, with the ability to run an input script entirely on the GPU(s) until a timestep on which CPU calculations are required. See this section of the manual for details.
• (8/11) Added a USER-MISC package to make it simpler and quicker to add new single-file features contributed by users to the main LAMMPS distribution. See this page for guidelines on how to submit code for a new feature.
• (8/11) Added support for the FFTW3 package as well as KISSFFT (which requires no link to an external FFT library), when using PPPM for long-range Coulombics.
• (6/11) Significant features added to LAMMPS in the second quarter of 2011 include atom_style sphere and ellipsoid, PPPM support added to GPU pacakge, pair_style rebo, system option with shell command, compute slice, dump image, USER-AWPMD package, and pair_style adp. See authors here and details here
• (6/11) Option to build LAMMPS from C++ source on a Windows box via Microsoft Visual Studio.
• (6/11) New dump image command for writing out ray-traced JPG or PPM image files from a running simulation.
• (3/11) Significant features added to LAMMPS in the first quarter of 2011 include 64-bit integers for atom and timestep count, temperature-accelerated dynamics (TAD), pair_style lj/charmm/coul/long/gpu, -var variables with multiple strings on command-line, ReaxFF examples, upgrades to the COMB and MEAM and PeriDynamics and eFF and AIREBO potentials, compute cluster/atom, option to calculate neighbors of ghost atoms, and fix langevin zero. See authors here and details here
• (1/11) New tad command for performing temperature accelerated dynamics (TAD) in multi-replica mode.
• Old

This is work by Sergey Zybin (zybin at wag.caltech.edu) and collaborators at Caltech to model shock-induced instabilities in explosive materials which have heterogeneous features, such as defects or interfaces, using the ReaxFF force field.

The figure shows shock loading of PBX in a 3.6M atom model with a saw-tooth interface between RDX and its polymer binder. The color represents slip which is highest at the interface.

This paper has further details:

Elucidation of the dynamics for hot-spot initiation at nonuniform interfaces of highly shocked materials, Qi An, Sergey V. Zybin, William A. Goddard III, Andres Jaramillo-Botero, Mario Blanco, and Sheng-Nian Luo, Phys Rev B, 84, 220101 (2011). (abstract)