There are 2 ways to get the LAMMPS software. You can follow the download instructions on this page to grab a tarball. Or if you have Subversion (SVN) or Git installed on your machine, you can use SVN or Git checkout and update commands to get the current version. Instructions on this are below for SVN and Git. Either way, once you have the code, follow the instructions in the LAMMPS documentation to build it.
To determine what version of LAMMPS you already have, or to stay up-to-date as features or bug-fixes are made to LAMMPS, see this page.
You can download older versions of LAMMPS, by going to this page and selecting the version you want, based on the date in the tarball filename. Not every version is available, because LAMMPS is updated frequently, and we have limited space on our WWW server.
Older parallel MD codes (ParaDyn, LJ) and the Python-based Pizza.py package, which provides pre- and post-processing and viz tools for LAMMPS, are available for download from this page.
Select the code you want, click the "Download Now" button, and your browser should download a gzipped tar file. Unpack it with the following commands, and look for a README to get you started.
gunzip file.tar.gz tar xvf file.tar
All versions of LAMMPS are distributed under the terms of the GNU Public license. The earlier Fortran versions are no longer under active development.
There have been ~101,400 downloads of LAMMPS from Sept 2004 thru Dec 2011.
You must have the Subversion (SVN) client software installed on your system to communicate with the public SVN server for LAMMPS.
Once SVN is installed, the following command will do an initial check-out of LAMMPS from an SVN server at Temple University, setup by Axel Kohlmeyer.
svn co svn://svn.icms.temple.edu/lammps-ro/trunk mylammps
where "mylammps" is the name of the directory you wish to create on your machine. Once the command completes, that directory should contain exactly the same files as if you unpacked the current LAMMPS tarball. The one EXCEPTION is that no LAMMPS packages are initially installed in the SVN src dir (a few packages are installed by default in the tarball src dir). Of course, you can install whichever ones you want before building LAMMPS; type "make package" from the src dir to see the options, and this section of the manual for a discussion of packages.
Note that you never need to do another svn check-out unless you want to start from scratch.
Thereafter, as bug fixes and new features are added to LAMMPS, as listed on this page, you can stay up-to-date by typing the following SVN command from within the "mylammps" directory:
svn update
You can also check if there are any updates by typing:
svn -qu status
Doing an update will not change any files you have added to the LAMMPS directory structure. It will also not change any existing LAMMPS files you have edited, unless those files have changed in the repository. In that case, SVN will attempt to merge the new repository file with your version of the file and tell you if there are any conflicts. See the SVN documentation for details.
Note that once you have done an "svn update", you still need to re-build LAMMPS if any source files have changed. To do this, you should cd to the src directory and type:
make package-update # since some changed files may be in package dirs make foo # for your machine
just as described on this page, as if a patch had been installed.
IMPORTANT NOTE: If you wish to edit/change a src file that is from a package, you should edit the version of the file inside the package sub-dir of src, then re-install the package. The version in the src dir is merely a copy and will be wiped out if you type "make package-update".
The SVN repository at Temple is a mirror of the master SVN repository for LAMMPS at Sandia. The mirroring occurs once per day, in the middle of the night.
IMPORTANT NOTE: The Temple SVN repository supports only the "svn://" access protocol for anonymous read-only access. It does NOT support the "http://" or "https://" access protocols.
Many thanks to Axel Kohlmeyer (Temple U) and Bill Goldman (Sandia) for setting up this SVN capability.
You must have Git installed on your system to communicate with the public Git server for LAMMPS.
The Git server is a mirror of the SVN server. Both are at Temple University, and were setup by Axel Kohlmeyer. Its URL is
http://git.icms.temple.edu/lammps-ro.git
Once Git is installed on your box the clone command to create a local copy of LAMMPS is
git clone http://git.icms.temple.edu/lammps-ro.git mylammps
where "mylammps" is the name of the directory you wish to create on your machine. Once the command completes, that directory should contain exactly the same files as if you unpacked the current LAMMPS tarball. The one EXCEPTION is that no LAMMPS packages are initially installed in the Git src dir (a few packages are installed by default in the tarball src dir). Of course, you can install whichever ones you want before building LAMMPS; type "make package" from the src dir to see the options, and this section of the manual for a discussion of packages.
See the discussion above about the SVN repository for how to keep your local version up to date and rebuild LAMMPS as needed, replacing SVN commands with their Git counterparts. E.g. issuing this command periodically
git pull
should keep your version up-to-date with the main LAMMPS repository.
IMPORTANT NOTE: The Temple Git repository supports both the "git://" and "http://" access protocols for anonymous read-only access. It does NOT support the "https://" access protocol.
Thanks to Axel Kohlmeyer (Temple U) for setting up this Git capability.
This page describes individual new features and bug fixes for LAMMPS. Each entry gives a "patch file" and a "list of changed files". The latter tells you what files the patch modifies in case you have edited those files yourself.
patch -bp1 < patch.12Dec04
IMPORTANT NOTE: If you wish to edit/change a src file that is from a package, you should edit the version of the file inside the package sub-dir of src, then re-install the package. The version in the src dir is merely a copy and will be wiped out if you type "make package-update".