LAMMPS Patch Release Overview

What is LAMMPS primarily used for?

LAMMPS has potentials for solid-state materials (metals, semiconductors) and soft matter (biomolecules, polymers) 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. Many of its models have versions that provide accelerated performance on CPUs, GPUs, and Intel Xeon Phis. The code is designed to be easy to modify or extend with new functionality.

Changes since the patch release 30 June 2020:

  • New compute style mliap for MLIAP package (Aidan Thompson, SNL) PR #2211, PR #2228
  • New fix style bond/create/angle for the MC package that restricts which bonds are created by the angle formed (Oliver Henrich, Strathclyde U), PR #2206
  • New command reset_mol_ids that will reassign molecule IDs based on topology data. This can be applied to the entire system or a subset. (Steve Plimpton SNL, Jake Gissinger U Colorado, Axel Kohlmeyer Temple U) PR #2218
  • Bugfixes and cleanups for several manybody styles in the GPU package which were giving inconsistent results for potential files with multiple elements (Trung Nguyen, Northwestern U), PR #2216
  • New fix style widom to model Widom insertions based on fix gcmc for MC package (Evangelos Voyiatzis, Royal DSM) PR #2230
  • Add feature to compute chunk/atom to return the number of chunks in scalar context (Axel Kohlmeyer, Temple U) PR #2212
  • Add support for writing complete data files for atom styles ellipsoid, line, tri, and body (Steve Plimpton, SNL and Axel Kohlmeyer, Temple U PR #2219
  • Add more unit tests and test inputs for commands, atom styles, pair styles, and kspace styles and change the reference output generator code to output forces sorted by atom ID (Axel Kohlmeyer, Temple U) PR #2205, PR #2214, PR #2234
  • Add pair style hybrid support for the KOKKOS version of the ReaxFF implementation (Stan Moore, SNL) PR #2231, PR #2236
  • Some refactoring in the KIM package to follow coding guidelines more closely and take advantage of C++11 and utility functions in LAMMPS (Yaser Afshar, UMN and Axel Kohlmeyer, Temple U) PR #2238
  • Documentation refactoring that splits overloaded pages into multiple pages (Richard Berger, Temple U) PR #2204
  • Various small updates and corrections (multiple authors) PR #2202, PR #2203 , PR #2205, PR #2210, PR #2220, PR #2226, PR #2227, PR #2229, PR #2237, PR #2239, PR #2241

Backward compatibility notices:

  • The shape parameters for ellipsoids are now output as diameters as documented. Previously it were radii so now their values are doubled.
  • The reset_ids command has been renamed to reset_atom_ids
  • The semantics of the compute fragment/atom have been changed due to significant performance optimizations. Please review the documentation for details.

This release has 2 assets:

  • Source code (zip)
  • Source code (tar.gz)

Visit the release page to download them.

New LAMMPS Patch released from Sandia


LAMMPS (Large-scale Atomic/Molecular Massiveley Parallel Simulator) is an open-source molecular dynamics simulator written in C++ from Sandia National Laboratories, and is designed for parallel machines. LAMMPS models an ensemble of particles in a liquid, solid or gaseous state. It can model atomic polymeric, biological, metallic, or mesoscale systems using a variety of force fields and boundary conditions and is easily extensible.