## LAMMPS

LAMMPS = Large-scale Atomic/Molecular Massively Parallel Simulator

This is the documentation for the LAMMPS 99 version, written in F77, which has been superceded by more current versions. See the LAMMPS WWW Site for more information.

LAMMPS is a classical molecular dynamics code designed for simulating molecular and atomic systems on parallel computers using spatial-decomposition techniques. It runs on any parallel platform that supports the MPI message-passing library or on single-processor workstations.

LAMMPS 99 is copyrighted code that is distributed freely as open-source software under the GNU Public License (GPL). See the LICENSE file or www.gnu.org for more details. Basically the GPL allows you as a user to use, modify, or distribute LAMMPS however you wish, so long as any software you distribute remains under the GPL.

Features of LAMMPS 99 include:

- short-range pairwise Lennard-Jones and Coulombic interactions
- long-range Coulombic interactions via Ewald or PPPM (particle-mesh Ewald)
- short-range harmonic bond potentials (bond, angle, torsion, improper)
- short-range class II (cross-term) molecular potentials
- NVE, NVT, NPT dynamics
- constraints on atoms or groups of atoms
- rRESPA long-timescale integrator
- energy minimizer (Hessian-free truncated Newton method)

More details about the code can be found here, in the HTML-based documentation. There is also a conference paper describing the parallel algorithms used in the code:

S. J. Plimpton, R. Pollock, M. Stevens, "Particle-Mesh Ewald and rRESPA for Parallel Molecular Dynamics Simulations", in Proc of the Eighth SIAM Conference on Parallel Processing for Scientific Computing, Minneapolis, MN, March 1997.

LAMMPS was originally developed as part of a 5-way CRADA collaboration between 3 industrial partners (Cray Research, Bristol-Myers Squibb, and Dupont) and 2 DoE laboratories (Sandia National Laboratories and Lawrence Livermore National Laboratories).

The primary author of LAMMPS is Steve Plimpton, but others have written or worked on significant portions of the code:

- Roy Pollock (LLNL): Ewald, PPPM solvers
- Mark Stevens (Sandia): rRESPA, NPT integrators
- Eric Simon (Cray Research): class II force fields
- Todd Plantenga (Sandia): energy minimizer
- Steve Lustig (Dupont): msi2lmp tool
- Mike Peachey (Cray Research): msi2lmp tool

Other CRADA partners involved in the design and testing of LAMMPS are

- John Carpenter (Cray Research)
- Terry Stouch (Bristol-Myers Squibb)
- Jim Belak (LLNL)

LAMMPS is copyrighted code that is distributed freely as open-source software under the GNU Public License (GPL). See the LICENSE file or www.gnu.org for more details. Basically the GPL allows you as a user to use, modify, or distribute LAMMPS however you wish, so long as any software you distribute remains under the GPL.

If you have questions about LAMMPS, please contact me:

Steve Plimpton
  sjplimp@sandia.gov
  www.cs.sandia.gov/~sjplimp
  Sandia National Labs
  Albuquerque, NM 87185

### More Information about LAMMPS

- Basics
- how to make, run, and test LAMMPS with the example problems
- Input Commands
- a complete listing of input commands used by LAMMPS
- Data Format
- the data file format used by LAMMPS
- Force Fields
- the equations LAMMPS uses to compute force-fields
- Units
- the input/output and internal units for LAMMPS variables
- Crib
- a one-line description of the variables used in LAMMPS
- History
- a brief timeline of features added to LAMMPS