LAMMPS 2026 software free download is a chemistry software for molecular dynamics code with a focus on materials modeling. Large-scale Atomic/Molecular Massively Parallel Simulator is a molecular dynamics program from Sandia National Laboratories. LAMMPS makes use of Message Passing Interface for parallel communication.
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 features
- runs on a single processor or in parallel
- distributed-memory message-passing parallelism (MPI)
- spatial-decomposition of simulation domain for parallelism
- open-source distribution
- highly portable C++
- optional libraries used: MPI and single-processor FFT
- GPU (CUDA and OpenCL), Intel Xeon Phi, and OpenMP support for many code features
- easy to extend with new features and functionality
- runs from an input script
- syntax for defining and using variables and formulas
- syntax for looping over runs and breaking out of loops
- run one or multiple simulations simultaneously (in parallel) from one script
- build as library, invoke LAMMPS through library interface or provided Python wrapper
- couple with other codes: LAMMPS calls other code, other code calls LAMMPS, umbrella code calls both
Few highlights of LAMMPS 4 July 2026
New Features and Additions
- Update the bundled Kokkos library to version 5.1.0 (Stan Moore, SNL and the Kokkos developers).
- Add new GRANSURF package with fixes and a pair style to model granular surfaces from triangles or line segments (Steve Plimpton, Joel Clemmer and Dan Bolintineanu, SNL).
- Add fix graphics/chunk command that renders convex hulls for chunks of atoms (Axel Kohlmeyer, Temple U).
- Add fix graphics/replica command that renders atoms from other replicas of a multi-replica simulation (Axel Kohlmeyer, Temple U).
- Add option to dump images to color bonds by property and improve fix graphics/labels to display atom colormaps, bonds and grids (Axel Kohlmeyer, Temple U).
- Add fix baoab command implementing a BAOAB Langevin integrator (Aram Davtyan, Deep Origin Inc.).
- Add fix gemc command implementing Gibbs-Ensemble Monte Carlo (Andrew Y. K. Hong, Aidan Thompson, and Stan Moore, SNL).
- Add ILVES constraint solver (Axel Kohlmeyer, Temple U with assistance from Lorién López Villellas, Universidad de Zaragoza).
- Add kspace style ESP (FFT based like PPPM) and related pair styles (Jiuyang Liang, Libin Lu, and Shidong Jiang, Flatiron Institute).
- Add pair style ldd to the BOCS package (Maria C. Lesniewski, Michael R. DeLyser, and Will G. Noid, Penn State).
- Add kspace_modify slab auto option to optimize slab size for quasi-2D simulations.
- Add pair style airebo/bc for a bond-centric AIREBO model.
- Add new styles to the OPENMP and KOKKOS packages.
- Add run style verlet/rk and kspace style pppm/rk as alternatives for very high MPI rank counts.
- Updates for the CG-DNA package with new styles and major refactoring.
- Updates and improvements for the GRAPHICS package.
- Updates and improvements to the DPD-REACT package.
- Add option to enable auto-tuning for some KOKKOS styles.
- Add ML-RUNNER package for machine learning potentials using the RuNNer Fortran library.
- Add pair styles coul/cut/soft/gapsys and lj/cut/soft/gapsys to the FEP package.
- Add bond valence and bond valence vector pair styles.
- Add bond style quartic/exp.
- Add a history keyword to fix store/state to store a rotating buffer of states.
- Add support for charge-charge and charge-dipole interactions to pppm/dipole.
Improvements and Updates
- Refactor color management to avoid stale pointers in color lists.
- Refactor memory management for variables.
- Refactor EAM pair styles for better code sharing and simpler inheritance.
- Fix bugs for unions or intersections of regions that may be translated or rotated.
- Support neighbor list binning using a hash table for dilute and highly polydisperse systems.
- Improved neighbor list configuration output for neighbor list style multi.
- Improved implementation for the bpm/rotational bond style to address particle ordering dependencies in force and torque calculations.
- Remove support for obsolete Intel Xeon Phi and KNL/MIC hardware from the INTEL package.
- Support slab correction with triclinic cells.
- Support triclinic cells with pppm/disp.
- Port kspace style ewald to the GPU package.
- Add Howto documentation and Python script for modeling dual-band EAM modules using eam/fs and hybrid/overlay pair styles.
- Add unit testing infrastructure for testing and validating granular/DEM models.
- Enhancement to unit testing for force styles to enable testing the KOKKOS package with Serial, OpenMP, CUDA, HIP and SYCL backends.
- Support single and mixed precision tests and add a workflow for post-merge CPU KOKKOS checks.
