LAMMPS Patch Release 31 August 2021

LAMMPS Patch Release Overview

What is LAMMPS used for?

LAMMPS is a classical molecular dynamics (MD) code that models ensembles of particles in a liquid, solid, or gaseous state. It can model atomic, polymeric, biological, solid-state (metals, ceramics, oxides), granular, coarse-grained, or macroscopic systems using a variety of interatomic potentials (force fields) and boundary conditions. It can model 2D or 3D systems with only a few particles up to millions or billions.

LAMMPS can run on single processor laptops or desktops, but is designed for parallel computers using message-passing techniques and a spatial-decomposition of the simulation domain. This includes shared-memory boxes and distributed-memory clusters and supercomputers. 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.

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Changes since the 30 July 2021 patch release:

• Add KOKKOS accelerated styles for shear flow simulations with the nvt/sllod integrator (Emily Kahl, The University of Queensland) PR #2882
• New fix ttm/grid for with improved file handling and distributed grid. The existing ttm fixes are refactored and modernized. This also generalizes and unbundles the grid communication class from the KSPACE package and thus updates all PPPM and MSM kspace style variants accordingly (Steve Plimpton, SNL) #2902
• New pair style coul/exclude to remove excluded Coulomb interactions and for use with kspace style scafacos for molecular systems (Axel Kohlmeyer, Temple U) PR #2886
• Add functionality to fix property/atom to support per-atom arrays in addition to per-atom vectors (Steve Plimpton SNL) PR #2342, PR #2889 PR #2903
• Update the COLVARS package to version 2021-08-06 (Giacomo Fiorin, NIH, and the colvars developers) PR #2863 and PR #2866
• Update to fix bond/swap to support a second kind of bond swapping model (Steve Plimpton, SNL) PR #2888
• File reader refactor, bug fixes, and unit tests for INTERLAYER package pair styles (Axel Kohlmeyer, Temple U) PR #2879, PR #2897
• Optimizations for SNAP with KOKKOS for large systems (enabled via config option) (Evan Weinberg, Nvidia) PR #2905
• Various updates and bugfixes for the KOKKOS package (Stan Moore, SNL) PR #2890, #2900
• Update factory functions to create or replace fixes and computes to return a pointer to the created class instance (Axel Kohlmeyer, Temple U) PR #2869
• Updates to the introductory pages of the LAMMPS documentation (Axel Kohlmeyer, Temple U) PR #2893
• Many small bug fixes, minor code improvements, and coding style, build system, documentation, formatting updates (multiple authors) PR #2804, PR #2862, PR #2861, PR #2865, PR #2868, PR #2876, PR #2880, PR #2881, PR #2885, PR #2887, PR #2889, PR #2891 , PR #2895, PR #2896, PR #2904, PR #2908, PR #2909, PR #2910, PR #2911, PR #2912, PR #2913, PR #2914

Backward compatibility notices:

• MC package fixes atom/swap, gcmc, widom, and charge/regulation were under some circumstances calling fixes that normally would be called at the "end_of_step()" stage during a time step instead in the "pre_exchange()" stage. This could lead to unexpected output or use of data from the previous time step (e.g. with fix print, fix ave/time etc.). These calls have been removed and the expected behavior has been restored.
• the output file format for the fix ttm electron temperature grid files has changed

This release has 2 assets:

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

Visit the release page to download them.

About LAMMPS

LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) a classical molecular dynamics simulation code designed to run efficiently on parallel computers. It was developed at Sandia National Laboratories, a US Department of Energy facility, with funding from the DOE. It is an open-source code, distributed freely under the terms of the GNU Public License (GPL).