Newest Features and Bug Fixes in LAMMPS

This page lists new features and bug fixes in the LAMMPS molecular dynamics package since the most recent major release was made. See the unfixed bug page for info on as-yet unresolved bugs.

To add these features/fixes to your version of LAMMPS, you have 2 choices. You can download the current tarball from the download page which includes all the new features/fixes listed below, and re-build LAMMPS from scratch. Or you can apply individual patch files to your copy of LAMMPS and do an incremental re-build, as described below. Note that for the latter, you must apply all patches in chronological order, starting from the date of your copy of LAMMPS, to stay up-to-date.

The last major release of LAMMPS was the 9 Jan 2009 version.

IMPORTANT NOTE: If you browse the LAMMPS HTML doc pages from the LAMMPS WWW site, then they describe the most current, fully-patched version of LAMMPS, which has changed after the date listed above. These additions are described on this page. If you browse the HTML doc pages from the doc directory of the tarball you downloaded, then they will describe that tarball, whether it was the original version for the date listed above, or an upgraded tarball including features up to the date you downloaded it, again as described on this page. When the tarball unpacks, it will contain the date that corresponds to which version you downloaded. The PDF file included in the doc directory is not regenerated for every patch, so it always corresponds to the original version with the date listed above.

Applying patches:

• Download the patch file. You may have to shift-click in your browser to download the file instead of display it. Patch files have names like patch.12Dec04.
• Put the patch file in your top-level LAMMPS directory, where the LICENSE and README files are.
• Apply the patch by typing the following command from the top-level LAMMPS directory, where the redirected file is the name of the patch file.

  patch -bp1 < patch.12Dec04 
  

• A list of updated files print out to the screen. The -b switch creates backup files of your originals (e.g. src/force.cpp.orig), so you can manually undo the patch if something goes wrong.
• Type "make package-update" from the src directory to enforce consistency between the src and package directories. This is OK to do even if you don't use one or more packages. If you are applying several patches, you only need to type "make package-update" once at the end.
• Re-make LAMMPS and you have the bug-fix or new feature.

Additional notes:

• The link to a "list of changed files" will tell you what files the patch modifies in case you have edited those files yourself. Note that for source files in a package (a sub-directory of src), the master copy of the file is in the sub-directory. The copy in src will also be overwritten if ,you use the "make package-update" command as described above.

21 Nov 2009

Bring the python tool files imported from Pizza.py up-to-date, so that the dump tool will write out write self-describing LAMMPS dump files, with atom column info. E.g. the dumpsort.py script will sort each snapshot by atom ID.

This patch file can be applied to the 20 Nov 2009 version. This is the list of changed files.

Thanks to Kelly Anderson (P&G) for pointing out this deficiency.

20 Nov 2009

Fixed a small memory clean-up issue with the prd command when it exits.

This patch file can be applied to the 19 Nov 2009 version. This is the list of changed files.

Thanks to Michael Rieger (Fritz Haber Institute, Germany) for calling attention to this.

19 Nov 2009

Reformulated the fix wall/lj93, fix wall/lj126, and fix wall/colloid commands to be self-consistent. Each command can now be used to specify up to 6 flat walls, be used with lattice or box units, and have a velocity or oscillatory motion applied to the walls.

This patch file can be applied to the 18 Nov 2009 version. This is the list of changed files.

18 Nov 2009

Bohumir Jelinek (Mississippi State Univ) found a bug with using the compute temp/profile command as a temperature bias, e.g. with the fix nvt command, when running in parallel. This patch fixes it.

This patch file can be applied to the 17 Nov 2009 version. This is the list of changed files.

17 Nov 2009

Mike Brown (Sandia) sent some upgrades to his GPU pair styles and library. A couple of memory leaks are fixed as well.

Axel Kohlmeyer (Temple Univ) added a nowait option to his fix imd command, so that LAMMPS can continue to run even if the VMD visualization package is not running.

This patch file can be applied to the 16 Nov 2009 version. This is the list of changed files.

16 Nov 2009

Fixed a typo in the atom_style angle command, that was introduced up by the 12Nov09 patch. Surely this is the last bug on this!

This patch file can be applied to the 14 Nov 2009 version. This is the list of changed files.

14 Nov 2009

Forgot a couple of initializations in atom_style hybrid in the 12 Nov 2009 patch. Sigh.

This patch file can be applied to the 13 Nov 2009 version. This is the list of changed files.

13 Nov 2009

Fixed a logic bug in yesterday's patch.

This patch file can be applied to the 12 Nov 2009 version. This is the list of changed files.

12 Nov 2009

Generalized the way ghost atoms store velocity info (translational velocity, angular velocity, angular momentum), which is needed by some pair styles in order to computer pairwise interactions.

Before, this was a property of specific atom_styles. Now, the communicate vel command is used to turn on this option, which means any atom_style can be used in this way.

This change eliminates the need for a atom_style dpd command, so it and the associated DPD package have been removed. The pair_style dpd command is now in main LAMMPS, and not in a package.

This patch file can be applied to the 11 Nov 2009 version. This is the list of changed files.

11 Nov 2009

Added some colloid particle options, where colloids are finite-size spherical particles, typically modeled in some kind of background solvent. The three new options are:

• atom_style colloid
• pair_style yukawa/colloid
• fix wall/colloid

This patch file can be applied to the 10 Nov 2009 version. This is the list of changed files.

Thanks to Randy Schunk and Jeremy Lechman (Sandia) for working on these new options.

10 Nov 2009

Paul Crozier (Sandia) has added a DSMC pair style, which allows formulation of a Direct Simulation Monte Carlo (DSMC) model for low-density fluid flow. This is an initial vanilla implementation of DSMC; various enhanced models and boundary conditions can be added as time and interest permit.

This patch file can be applied to the 9 Nov 2009 version. This is the list of changed files.

9 Nov 2009

Axel Kohlmeyer (Temple Univ) created a USER-IMD package which leverages the work of the VMD and NAMD folks at U Illinois to allow a code like LAMMPS to connect in real-time to the VMD visualization package. This allows you to view real-time visualization of a running LAMMPS simulation as well as interact with the model, e.g. by dragging an atom with the mouse. See the doc page for the fix imd command for details.

This patch file can be applied to the 7 Nov 2009 version. This is the list of changed files.

7 Nov 2009

Alexander Stukowski (Technical University of Darmstadt, Germany) sent an extension to the embedded atom method (EAM) pair style known as concentration-dependent EAM (CD-EAM) for more accurate alloy modeling.

This patch installs it as a user package, which can be accessed via the new pair_style eam/cd command.

This patch file can be applied to the 6 Nov 2009 version. This is the list of changed files.

6 Nov 2009

Fixed a problem in the src/Make.csh script that is used to generate the Makefile.lib (and Makefile.list) for building LAMMPS as a library. This only seemed to affect the use of the tool on Macs, and is really due to a bug in the sed commmand on Macs not accepting the tab character. With this change, the script now works on a Mac as well.

This patch file can be applied to the 5 Nov 2009 version. This is the list of changed files.

Thanks to Patrick Varilly (UC Berkeley) and Jon Zimmerman (Sandia) for sending me fixes for this.

5 Nov 2009

Axel Kohlmeyer (Temple Univ) sent some small changes for his CMM coarse-grain model, in the USER-CG-CMM package.

This patch file can be applied to the 4 Nov 2009 version. This is the list of changed files.

4 Nov 2009

Fixed a bug in the pair_style dpd command when using non-LJ units. The derived sigma parameter was missing a Boltzmann constant.

This patch file can be applied to the 3 Nov 2009 version. This is the list of changed files.

Thanks to Dave Heine (Corning) for finding this bug.

3 Nov 2009

Fixed a bug with neighbor lists in pair_style hybrid command, when the I,I and J,J pair interactions are with one pair style, but I,J interactions are with another.

This patch file can be applied to the 2 Nov 2009 version. This is the list of changed files.

2 Nov 2009

Fixed a bug with the hybrid bond,angle,dihedral,improper styles and there use of the "none" option as part of the coefficient command, to turn off certain bond,angle,dihedral,improper types.

This patch file can be applied to the 1 Nov 2009 version. This is the list of changed files.

Thanks to Ting for identifying what the problem was.

1 Nov 2009

Fixed a one-line bug in the fix rigid command that sometimes messed up the processing of the "force" keyword.

This patch file can be applied to the 31 Oct 2009 version. This is the list of changed files.

Thanks to Chen Chen (Wuhan University) for finding this typo.

31 Oct 2009

Mike Brown (Sandia) implemented the parallel replica dynamics (PRD) method of Art Voter to allow accelerated dynamics to be performed for appropriate systems. Typically this is solid-state systems undergoing infrequent transition events.

PRD is invoked in LAMMPS via the new prd and compute event/displace commands. There is a also a new example directory lammps/examples/prd with a sample input script for vacancy diffusion in bulk Si.

This patch file can be applied to the 30 Oct 2009 version. This is the list of changed files.

30 Oct 2009

Axel Kohlmeyer (Temple Univ) and Paul Crozier (Sandia) modified the way lookup tables are used for efficient long-range Coulombic calculation as part of the pair_modify table command. Before, we were doing this in a non-standard way that sometimes caused problems with certain compilers at high levels of optimization. The new way should be ANSI-standard and no longer cause these problems.

This patch file can be applied to the 29 Oct 2009 version. This is the list of changed files.

29 Oct 2009

One more set of changes to the LAMMPS makefiles, in an attempt to maket them as clear and easy to edit as possible, when a user needs to create a low-level src/MAKE/Makefile.foo for a new platform. There are now sections for specifying settings for MPI, FFT, and package libraries needed by LAMMPS. The doc pages explains the format of the file.

Since I can't test all the Makefiles, please send edits if something doesn't work on a particular platform.

I also took this opportunity to delete some old Makefiles that I assumed no one uses anymore. If this is not the case, then complain.

This patch file can be applied to the 25 Oct 2009 version. This is the list of changed files.

25 Oct 2009

Paul Crozier (Sandia) created and posted a pre-built LAMMPS executable for Windows platforms on the download site. This does not include an MPI or FFT library, so it can only be run on a single processor. Nor does it include all LAMMPS packages; see the download page for details. It also only includes bug-fixes/upgrades listed on this page up to a certain date. Our plan is to periodically update the Windows executable to be close to the latest LAMMPS tarball. If you want something more current, or with more packages, you'll have to download the source tarball and build it yourself.

This patch file can be applied to the 14 Oct 2009 version. This is the list of changed files.

14 Oct 2009

Fixed a small bug in the fix aveforce and fix addforce commands with incorrectly parsing the optional keywords.

This patch file can be applied to the 13 Oct 2009 version. This is the list of changed files.

Thanks to Craig Tenney (U Notre Dame) for calling attention to this.

13 Oct 2009

Mike Brown (Sandia) has fixed a bug in the CUDA implementation of pair_style gayberne/gpu, resulting in insufficient memory allocation to hold the maximum number of aspherical particles.

This patch file can be applied to the 12 Oct 2009 version. This is the list of changed files.

Thanks to Davide Vanzo for reporting the problem.

12 Oct 2009

Mike Brown (Sandia) has some minor changes to his PyMol-based apspherical particle visualization tool, so that it compiles under gcc 4.0.

This patch file can be applied to the 29 Sept 2009 version. This is the list of changed files.

29 Sept 2009

Todd Plantenga (Sandia) has added a Hessian-free truncated Newton (hftm) minimization style to LAMMPS. It should converge quadratically when near the minimum (like a Newton method) and has the potential to achieve a higher accuracy than the conjugate gradient or steepest descent methods.

This patch file can be applied to the 28 Sept 2009 version. This is the list of changed files.

28 Sept 2009

Changed (yet again) the lo-level Makefiles in src/MAKE to allow the plethora of optional LAMMPS packages and their library dependencies to be managed more easily. And the platform-specific settings in those Makefiles to be more easily understood. See this section of the doc pages for gory details.

This patch file can be applied to the 24 Sept 2009 version. This is the list of changed files.

24 Sept 2009

Reese Jones, Jon Zimmerman, and Jeremy Templeton (Sandia) have worked a long time on creating a capability to couple continuum finite elements (FE) to atomistic calculations. This is the initial release of their user-atc package which is invoked through a new fix_atc command.

This patch file can be applied to the 22 Sept 2009 version. This is the list of changed files.

22 Sept 2009

Fixed a round-off bug when using triclinic simulation boxes with the displace_box or fix deform commands that could cause an atom near a periodic boundary to get remapped incorrectly on rare occasions.

This patch file can be applied to the 16 Sept 2009 version. This is the list of changed files.

Thanks to Sai Jayaraman (Sandia) for sending a test script with this problem.

16 Sept 2009

Greg Wagner (Sandia) made a small change to the MEAM library that fixes a small bug caused by round-off error that is occasionally hit when computing the screening function for collinear atoms.

This patch file can be applied to the 14 Sept 2009 version. This is the list of changed files.

Thanks to Bohumir Jelinek (Mississippi State) for tracking this down.

14 Sept 2009

Fixed a small bug with the new dump cfg command that prevented it from outputting per-atom compute quantities.

This patch file can be applied to the 7 Sept 2009 version. This is the list of changed files.

Thanks to Wang Zhiguo for identifying this issue.

7 Sept 2009

Paul Crozier (Sandia) and Carolyn Phillips (U Michigan) added a restart capability to their two-temperature model fix ttm command.

This patch file can be applied to the 6 Sept 2009 version. This is the list of changed files.

6 Sept 2009

Aidan Thompson (Sandia) added an append option to the dump_modify command so that you can append to an existing dump file on a subsequent run, so long as the "dump_modify" command is used before the new dump file is actually written to.

This patch file can be applied to the 5 Sept 2009 version. This is the list of changed files.

5 Sept 2009

At the suggestion of Craig Maloney (CMU), I changed the interpretation of the trate parameter of the fix deform command. It now has consistent 1/time units and modifies the box length or box tilt by a exp(trate*dt) factor that is a more traditional interpretation of a "true engineering strain or shear rate".

This patch file can be applied to the 4 Sept 2009 version. This is the list of changed files.

4 Sept 2009

Mike Brown (Sandia) made some small changes to the GPU library inovoked by pair_style lj/cut and pair_style gayberne to add barriers to kernels to prevent a possible race condition when there is more than 2 atom types. Probably a condition that would never occur in practice, but this is have more safe code.

Also, Ahmed Ismail (Sandia) made a small change to the ch2lmp tool for converting a LAMMPS dump file into a PDB file. This was needed to parse the current LAMMPS dump output which adds keywords for atom column info.

This patch file can be applied to the 2 Sept 2009 version. This is the list of changed files.

2 Sept 2009

Liang Wan (Chinese Academy of Sciences) has added a dump cfg command to write out dump files in the extended CFG format, suitable for visualizing with the AtomEye package. The extended format means that additional per-atoms values (velocity, energy, stress, etc) can be included and visualized accordingly, e.g. by coloring the atoms.

This patch file can be applied to the 1 Sept 2009 version. This is the list of changed files.

1 Sept 2009

Greg Wagner (Sandia) fixed a small bug in the pair_style meam potential for the reference energies of the L12 and C11 crystal structures.

This patch file can be applied to the 27 Aug 2009 version. This is the list of changed files.

27 Aug 2009

Andy Ballard (U Maryland) added Nose/Hoover chains to the fix nvt command. It can be turned on/off via the chain keyword, but they are now on by default. Chains provide a more robust NVT integrator, overcoming non-ergodic sampling issues and energy oscillations found with ordinary Nose/Hoover dynamics. This implementation uses one chain and integrates the equations of motion via a Trotter expansion good to 2nd order accuracy in the timestep size.

This patch file can be applied to the 25 Aug 2009 version. This is the list of changed files.

25 Aug 2009

Fixed a one-line bug with the 21Aug09 patch that messed up minimization with restart files.

This patch file can be applied to the 21 Aug 2009 version. This is the list of changed files.

Thanks to Rebecca Powles for flagging this problem.

21 Aug 2009

This is a bookkeeping patch that generalizes the interface to the verlet, respa, and minimize classes in LAMMPS. The purpose is to allow a new parallel replica dynamics (PRD) driver to work with both time integration and minimization together. We plan to release the PRD capability soon.

Also fixed a small bug in the minimizer with memory allocation, found by Liang Wan (Chinese Academy of Sciences).

This patch file can be applied to the 19 Aug 2009 version. This is the list of changed files.

19 Aug 2009

Greg Wagner (Sandia) made some small changes to the MEAM package to synchronize argument lists in function calls. The mismatch only seemed to cause a problem on a particular architecture.

This patch file can be applied to the 18 Aug 2009 version. This is the list of changed files.

Thanks to Rohit Ral for catching this problem.

18 Aug 2009

Made a small change to the quadratic linesearch in the energy minimizer so it will be more robust when performing anisotropic box relaxations via the fix box/relax command. This case is a hard one for the minimizer becuase the objective function being minimized and the gradient being used to satisfy the box size constraints do not exactly match.

This patch file can be applied to the 17 Aug 2009 version. This is the list of changed files.

Thanks to Aidan Thompson (Sandia) for help with this.

17 Aug 2009

Reorganized the files associated with the minimize command and its various min styles. This was for two reasons. First, to allow a non line-search minimizer, a Hessian-free truncated-Newton method, to be added, which will happen soon. Second, to allow additional per-atom degrees of freedom to be included in the minimizer. The latter is useful for a new force field that includes electron radius as a dynamic variable, which will also be added soon.

This patch file can be applied to the 16 Aug 2009 version. This is the list of changed files.

16 Aug 2009

The 7Aug09 patch which used the sed command to make packages with libraries easier to install/uninstall, appears not to be as portable as I assumed. I find it hard to believe, but "sed" does not work the same on Linux vs Mac. This patch fixes the problem by using some more vanilla sed commands.

This patch file can be applied to the 15 Aug 2009 version. This is the list of changed files.

Thanks to Aidan Thompson (Sandia) for running into this.

15 Aug 2009

The 9Aug09 patch which does some sanity checking on numeric arguments to force-field commands, didn't allow for the "+" sign to appear, e.g. in an exponent. This patch now allows for it.

This patch file can be applied to the 14 Aug 2009 version. This is the list of changed files.

Thanks to Volodymyr Babin (NCSU) for calling attention to this.

14 Aug 2009

Mike Brown (Sandia) has created a LAMMPS-specific NVIDIA GPU library and created two pair styles that work with it: pair_style lj/cut/gpu and pair_style gayberne/gpu. This means you can run those pairwise computations within LAMMPS in an accelerated fashion, on one or more NVIDIA GPU cards, assuming your system has them.

The speed-up you'll achieve depends on hardware (both CPU and GPU), the size of your system, the cutoff, and the relative expense of the pairwise computation itself. Mike has seen about a 4x speed-up for the Lennard-Jones potential, and about 100x for the GayBerne.

This section of the manual has background info on the use of GPUs with LAMMPS. We plan to add more GPU-enabled pair styles in the future.

This patch file can be applied to the 13 Aug 2009 version. This is the list of changed files.

13 Aug 2009

Chuanfu Luo wrote 3 new potentials: a 9/6 Lennard-Jones potential, a tabulated bond potential, and a tabulated angle potential.

This patch file can be applied to the 11 Aug 2009 version. This is the list of changed files.

11 Aug 2009

Carolyn Phillips (U Michigan) added a tally option to the fix langevin command to allow the cummulative energy added/subtracted to the system by the Langevin heat bath to be calculated, enabling the monitoring of energy conservation.

This patch file can be applied to the 10 Aug 2009 version. This is the list of changed files.

10 Aug 2009

Axel Kohlmeyer (Temple U) sent some additions to the fix addforce and fix aveforce commands, to allow them to be applied only to atoms in a geometric region.

This patch file can be applied to the 9 Aug 2009 version. This is the list of changed files.

9 Aug 2009

Added some error checking to the various force field definition commands (pair_style, pair_coeff, bond_coeff, angle_coeff, etc) to insure command arguments are valid floating point or integer values. This is to avoid some invalid input script commands that sometimes pass thru the parsing, particularly when users forget to add the pair_style name to a pair_coeff command when using the pair_style hybrid command.

This patch file can be applied to the 8 Aug 2009 version. This is the list of changed files.

8 Aug 2009

Enabled the spherical and cylindrical indenters in the fix indent command to work with periodic boundaries. The indenters can now straddle periodic boundaries or move across a periodic boundary and back into the simulation box.

This patch file can be applied to the 7 Aug 2009 version. This is the list of changed files.

7 Aug 2009

Due to some sed wizardry by Mike Brown (Sandia) we have streamlined the process to build LAMMPS with optional packages that have their own libraries (currently POEMS, MEAM, ReaxFF). Specifically you no longer need to maintain separate lo-level Makefiles, like Makefile.g++_meam, Makefile.g++_reax, etc to use the libraries and packages that wrap them. Once you have built the libraries themselves, you should be able to include/exclude them or use them in any combination, just as you would any normal LAMMPS package.

The details are in this section of the doc pages. And you can look at src/MAKE/Makefile.linux, src/MAKE/Makefile.g++, src/MAKE/Makefile.serial for examples of how to include the correct Fortran settings, if you want to use one of the Fortran-based libraries, like MEAM or ReaxFF.

This patch file can be applied to the 4 Aug 2009 version. This is the list of changed files.

4 Aug 2009

Made a small change to the fix heat command to have it always use the current timestep size for calculating heat flux. Thus it will adapt if the timestep changes.

This patch file can be applied to the 3 Aug 2009 version. This is the list of changed files.

3 Aug 2009

With help from David Heine (Corning), we found and fixed a bug in the fix bond/create command that sometimes allowed too many bonds to form per atom, exceeding the iparam and jparam limit settings.

This patch file can be applied to the 22 Jul 2009 version. This is the list of changed files.

22 Jul 2009

Added headers to the dump files written out by multiple processors, via the "%" wildcard in the dump file name. This is for the dump atom and dump custom commands. Without the headers, the files for processors other than 0 were hard to interpret, particularly if they contained multiple snapshots.

This patch file can be applied to the 21 Jul 2009 version. This is the list of changed files.

21 Jul 2009

Fixed a bug that showed up when the fix deposit command was used with rigid bodies, as setup by the fix rigid command. It had to do with attributes of added atoms not being initialized correctly.

This patch file can be applied to the 14 Jul 2009 version. This is the list of changed files.

Thanks to Thomas Siegfried for sending a script that illustrated the problem.

14 Jul 2009

Fixed a small bug in the velocity command with how it processed particles with per-particle mass (as opposed to the usual per-type mass).

This patch file can be applied to the 7 Jul 2009 version. This is the list of changed files.

Thanks to Fillion-Gourdeau for running into the problem.

New release of LAMMPS (C++ version). 148,035 lines of code in src dir with all packages included (but no library source files).

IMPORTANT: The output format of dump files in the native LAMMPS format has changed slightly. The BOX BOUNDS field adds "xy xz yz" for triclinic boxes which quantities are appended to the following 3 lines of lo/hi box bounds. The ATOMS field adds per-atom column descriptors such as "id type x y z". These are so the dump file is self-describing and can be more easily post-processed.

These are the most significant features added or enhanced since the 9 Jan 2009 version. People who contributed to the features are listed in parentheses:

• improvements to the energy minimizer (Aidan Thompson, Sandia)
• per-type and per-atom mass and size/shape
• more general fix rigid allowing for rigid bodies containing finite-size particles
• compute heat/flux for Green-Kubo thermal conductivity (Reese Jones, Sandia; Philip Howell, Siemens; Vikas Varsney, AFRL)
• compute cna/atom (Liang Wan, Chinese Academy of Sciences)
• pair_style reax (Aidan Thompson, Sandia; Hansohl Cho, MIT)
• fix box/relax (Aidan Thompson and David Olmsted, Sandia)
• group delete
• fix deform wiggle
• fix evaporate
• fix ttm (Paul Crozier, Sandia; Carolyn Phillips, U Michigan)
• compute reduce/region
• compute temp/profile
• pair_style born/coul/long (Ahmed Ismail, Sandia)
• fix reax/bonds (Aidan Thompson, Sandia)

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 138,720 lines of code in src dir with all packages included (but no library source files).

IMPORTANT: The syntax of the following commands has changed: pair_style gran/hooke, pair_style gran/hooke/history, pair_style gran/hertz/history, and special_bonds. The keyword "tag" in the dump custom command has been changed to "id". The default for specifying layer thicknesses in the fix ave/spatial command has been changed from box units to lattice units.

These are the most significant features added or enhanced since the 21 May 2008 version. People who contributed to the features are listed in parentheses:

• reworking of how variables and computes keep track of when they were invoked
• Peridynamics package for mesoscale modeling (Mike Parks, Sandia)
• auto-adjusting of the PPPM stencil
• upgraded Hertzian granular pair_style for polydisperse systems
• communicate cutoff
• pair_style tersoff/zbl (Dave Farrell, Northwestern U)
• fix indent plane
• fix wall/lj93 velocity (Aidan Thompson, Sandia)
• delete_atoms porosity (Jon Zimmerman, Sandia)
• special_bonds options
• fix bond/create
• fix bond/break

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 133,864 lines of code in src dir with all packages included (but no library source files).

IMPORTANT: For 2d problems using extended spherical particles (as opposed to point particles), such as granular or colloidal particles, the particles are now treated as 3d spheres moving in a 2d space. As opposed to 2d circular disks moving in a 2d space. This is simply a change in their moment of inertia, but will affect their dynamics when rotating due to an applied torque. Likewise it affects their temperature.

IMPORTANT: For 2d problems, the default for subtracting the system center-of-mass degrees-of-freedom when computing temperature was changed from 3 dof to 2 dof (for the entire system). This means you might see a slight change in reported temperature and subsequent dynamoics in a 2d simulation.

These are the most significant features added or enhanced since the 22 Jan 2008 version. People who contributed to the features are listed in parentheses:

• temperatures now have bias velocities which can be subtracted
• thermostats and temperature computations now work together more flexibly
• more robust line-search and stopping criteria in energy minimizer
• angle_style cosine/delta (Axel Kohlmeyer, U Penn)
• delete_atoms overlap between 2 groups of atoms
• compute group/group
• compute reduce
• fix temp/berendsen
• fix press/berendsen
• fix nve/sphere
• fix nvt/sphere
• fix npt/sphere
• compute temp/com
• compute temp/sphere
• compute erotate/sphere
• compute erotate/asphere
• lmp2vmd tool (Axel Kohlmeyer, U Penn)
• tool directory of Python post-processing scripts
• fix thermal/conductivity (Ed Maginn, UND)
• pair_style lj/gromacs (Mark Stevens, Sandia)
• pair_style lj/gromacs/coul/gromacs (Mark Stevens, Sandia)
• fix bond/swap
• USER-CG-CMM package for coarse-grained models (Axel Kohlmeyer, U Penn)
• USER-SMD package for steered MD (Axel Kohlmeyer, U Penn)

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 125,009 lines of code in src dir with all packages included (but no library source files).

IMPORTANT: Velocity initialization via the velocity command using the loop geom option now uses a new random number generation scheme, as do certain options of the set and displace_atoms commands. Hence an input script using these commands will initialize a system differently (i.e. statistically the same, but with a different set of random velocities). The following commands are deleted in this version, since they have been replaced by more general output options: "fix gran/diag", "compute epair/atom", "compute ebond/atom", "compute variable/atom", "compute variable", "compute sum/atom", and "compute attribute/atom".

These are the most significant features added or enhanced since the 5 Oct 2007 version. People who contributed to the features are listed in parentheses:

• LAMMPS output options for thermodynamic and dump output
• thermo_style custom and dump custom
• fix ave/time, fix ave/spatial, and fix ave/atom
• per-atom energy and virial tabulation for all potentials and internal constraint fixes
• easier-to-use variable formula syntax
• fix dt/reset
• pair_style lubricate (Randy Schunk, Sandia)
• pair coul/debye
• fix coord/original
• compute pe/atom
• compute stress/atom
• compute sum
• pair_style resquared (Mike Brown, Sandia)
• fix viscosity
• compute displace/atom

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 118,521 lines of code in src dir with all packages included (but no library source files).

IMPORTANT: The syntax of the fix ave/spatial, fix ave/time, and fix gravity commands has changed. The "compute etotal/atom" command was deleted and replaced by the more general compute sum/atom command. Some keywords for the dump custom command have been removed: epair, ke, etotal, centro, stress. These are now invoked by creating a compute of the appropriate style and referencing it in the dump custom command.

These are the most significant features added since the 22 Jun 2007 version. People who contributed to the features are listed in parentheses:

• displace_box
• change_box
• compute ebond/atom
• changes to 2d pressure computation
• rigid bodies with fix deform
• pair_style airebo (Ase Henry, MIT)
• fix nve/limit
• fix ave/atom
• compute attribute/atom
• compute sum/atom
• user-contributed packages
• pair_style hybrid/overlay for superposing pairwise potentials
• kspace_style ewald/n for long-range dispersion contributions from 1/r^6 LJ terms (Pieter in 't Veld, SNL)
• pair_style lj/coul (Pieter in 't Veld, SNL)
• pair_style buck/coul (Pieter in 't Veld, SNL)
• compute ackland/atom (Gerolf Ziegenhain)

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 106,005 lines of code in src dir (with all packages included).

IMPORTANT: The format of restart files was changed to make it easier to add new atom info in the future. Thus this version will not read restart files created by older versions. For hybrid atom styles, the format of atom lines in input data files was changed. The syntax of the create_atoms command was changed. The fix volume/rescale and fix uniaxial commands were deleted since their functionality is now present in the fix deform command.

These are the most significant features added since the 12 Feb 2007 version. People who contributed to the features are listed in parentheses:

• static and dynamic non-orthogonal simulation boxes (Pieter in 't Veld, SNL)
• fix heat (Paul Crozier, SNL)
• input script if command
• new Finnis/Sinclair EAM potentials (Mikhail Mendelev, Ames Lab)
• displace_atoms random
• new set command options
• create_atoms single
• compute coord/atom
• fix ave/time (Pieter in 't Veld, SNL)
• fix ave/spatial (Pieter in 't Veld, SNL)
• variable atom
• COLLOID package with pair colloid potential (Pieter in 't Veld, SNL)
• neighbor multi option (Pieter in 't Veld, SNL)
• communicate multi option (Pieter in 't Veld, SNL)
• DIPOLE package for point-dipole particles with pair dipole/cut
• ASPHERE package for ellipsoidal particles with a GayBerne potential (Mike Brown, SNL)
• aspherical particle integrators (Mike Brown, SNL)
• NEMD simulations via fix deform and fix nvt/sllod and compute temp/deform (Pieter in 't Veld, SNL)
• PyMol viz converter pymol_asphere for ellipsoidal particles (Mike Brown, SNL)

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 95,029 lines of code in src dir (with all packages included).

IMPORTANT: The temperature command was replaced by the compute command in this release, which is now a more flexible way to define global calculations (temp, pressure, etc) and per-atom calculations (energy, stress, etc) which can be output as thermodynamic and dump info or be accessed by input script variables.

There were also minor changes in the hi-level code structure to make LAMMPS more library-friendly.

These are the most significant features added since the 1 Oct 2006 version. People who contributed to the features are listed in parentheses:

• Tersoff potential (Aidan Thompson, SNL)
• Stillinger-Weber potential (Aidan Thompson, SNL)
• MEAM (modified EAM) potential (Greg Wagner, SNL)
• non-orthogonal lattices
• fix wall/lj126 (Mark Stevens, SNL)
• fix deposit
• uloop variables
• removal of global variables so LAMMPS can be instantiated multiple times (Ben FrantzDale, RPI)
• optimized versions of lj/cut, eam, morse, and lj/charmm/coul/long pair potentials (James Fischer; High Performance Technologies), David Richie and Vincent Natoli (Stone Ridge Technologies)
• compute command
• new options for thermo_style custom
• new options for dump custom
• new options for variable equal
• higher-precision real/metal units (Paul Crozier, SNL)

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 85,559 lines of code in src dir (with all packages included).

IMPORTANT: The storage of periodic box image flags in restart files changed with this release. The current version will still read old restart files, but the values of the image flags will be wrong if you use them in a computation or subsequently output them (e.g. in a dump file).

There were also changes in the hi-level code structure and in pair style routines. These were for the purpose of making LAMMPS more library friendly and in anticipation of new many-body potentials we hope to release soon (Stillinger-Weber, Tersoff, REBO, etc).

These are the most significant features added since the 17 Jul 2006 version. People who contributed to the features are listed in parentheses:

• dihedral_style opls (Mark Stevens, SNL)
• allow 2d granular simulations
• allow per-processor restart files to be written
• shell command for using cd, mkdir, mv, rm, rmdir in input scripts
• lattice diamond style
• several new options for run command
• fix gyration (Naveen Michaud-Agrawal, JHU)
• fix recenter (Naveen Michaud-Agrawal, JHU)
• fix momentum (Naveen Michaud-Agrawal, JHU)
• new set command options for atom attributes
• multi-letter variables in input scripts (Naveen Michaud-Agrawal, JHU)
• equal style variables can compute group properties (Naveen Michaud-Agrawal, JHU)
• read_restart can read latest restart file
• LJ tail corrections via pair_modify option (Paul Crozier, SNL)

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 82,729 lines of code in src dir (with all packages included).

These are the most significant features added since the 12 Apr 2006 version. People who contributed to the features are listed in parentheses:

• fix wall/reflect command
• fix spring/self, and fix spring/rg commands (Naveen Michaud-Agrawal, Johns Hopkins U and Paul Crozier, SNL)
• enhanced fix langevin command to include a region option
• pair_style lj/smooth potential (Craig Maloney, UCSB)
• fix orient/fcc command for driving grain boundary motion (Koenraad Janssens and David Olmsted, SNL)
• dump dcd and dump xtc styles (Naveen Michaud-Agrawal, Johns Hopkins U)
• temperature region style for computing temperatures on geometric regions of atoms
• thermo_style custom t_ID option for printing one or more user-defined temperatures as thermodynamic output
• bond_style quartic (Mark Stevens and Chris Lorenz, SNL)
• faster pair_style hybrid potential (James Fischer, High Performance Technologies, Inc; Vincent Natoli and David Richie, Stone Ridge Technology)
• angle_style hybrid, dihedral_style hybrid, improper_style hybrid potentials
• delete_atoms overlap option for deleting created atoms that are too close
• TIP4P water potential (Ahmed Ismail and Amalie Frischknecht, SNL)
• dumping of per atom energy, stress, centro parameters during energy minimization
• fix poems command which hooks to the POEMS library from RPI to simulate the motion of coupled rigid bodies (Rudranarayan Mukherjee, RPI)

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 74,353 lines of code in src dir (with all packages included).

IMPORTANT: The syntax of these commands were changed. If you use these commands, you will need to modify your existing input scripts:

• Atom_style eam no longer exists; atom_style atomic can be used instead.
• Pair_style eam was split into 2 styles. Style eam is for EAM funcfl files (single element); style eam/alloy is for EAM setfl files (alloy).
• The arguments for fix temp/rescale command were reordered so the N value comes first, to be consistent with similar fixes.

These are the most significant features added since the 10 Nov 2005 version. People who contributed to the features are listed in parentheses:

• energy minimization via minimize, min_style, and min_modify commands
• dissipative particle dynamics (DPD) atom style and pair style potential (Kurt Smith, U Pitt and Frank van Swol, Sandia)
• time-averaged thermo output of several quantities
• Finnis/Sinclair variant of EAM pairwise potentials (Tim Lau, MIT)
• angle style cosine/squared and dihedral style helix (Naveen Michaud-Agrawal, JHU)
• dump options for creating per-snapshot, per-atom, and gzipped output files
• dump_modify options for outputting atoms within geometric regions and on threshhold criteria
• input script functionality: print command, fix print command, label command, jump command, more variable options, command-line argument -echo
• fix uniaxial command (Carsten Svaneborg, Max Planck Institute)
• more flexible thermo_style custom command; fixes can generate thermo output
• changes to fix npt to dilate around the box center more efficiently

Though previously advertised, TIP4P pairwise potentials and a bond_style restrain potential are not part of this release. They will be added as patches in the near future.

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 68,545 lines of code in src dir (with all packages included).

These are the most significant features added since the 3 Jun 2005 version:

• new or enhanced fix efield, fix indent, fix spring, fix nph, and fix gravity commands
• new option for fix nvt, fix npt, fix nph commands to damp oscillations
• new union and intersect region styles for creating complex geometric regions
• release of Pizza.py Toolkit, a Python-based collection of tools for setup, analysis, plotting, and visualization of LAMMPS data

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 66,806 lines of code in src dir (with all packages included).

The format of binary restart files changed with this version, due to hybrid atom and pair styles and the changes to enable very large simulations. Hence this version will NOT read older version's restart files.

Also, starting with this version, a build of LAMMPS will NOT include all optional packages by default. In particular the "granular" and "class2" packages will not be included unless you request them. See the Making LAMMPS section of the documentation for more details or type "make package" when building LAMMPS to see the options.

These are the most significant features added since the 17 Jan 2005 version:

• pair and intra-molecular potentials for class 2 interactions (the COMPASS force field of Accelrys) that were originally in LAMMPS 2001
• enable simulations with more than 2^31 (2 billion) atoms via memory and other changes
• simulation of mixed systems via a hybrid pair_style and hybrid atom_style
• read in pre-tabulated pair potential via the pair_style command
• Buckingham, Morse, Yukawa pair potentials for the pair_style command
• Morse bond potential for the bond_style command
• include command
• radial distribution functions (fix rdf)
• dump out tabulated pair potential file (pair_write)
• dump per-atom energy and stress (dump custom)

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

New release of LAMMPS (C++ version). 56,612 lines of code in src dir (with all packages included). These are the most significant features added since the 1 Sept 2004 version:

• better integrator for rigid bodies (fix rigid)
• centro-symmetry parameter via dump command (dump custom)
• targeted molecular dynamics option (fix tmd)
• code partitioned into optional packages (make)
• wild-carding enabled for several input script commands (mass, pair_coeff, bond_coeff, etc)
• pre-compute tables for pairwise portion of long-range Coulombic solvers (pair_modify)
• native FFT support for SGI machines via SCSL library
• new versions of post-processing tools for connecting LAMMPS to Accelrys Insight (tools)
• bond_style hybrid enables use of multiple bond styles (bond_style)
• generalized set_type command for atoms, bonds, etc (set)

Descriptions of all these enhancements and other bug fixes can be viewed on this page.

There is also a new release of LAMMPS 2001 (F90 version), which contains a few minor tweaks and bug fixes. These are included in the 2001 tar file now available from the download page.

1 Sept 2004

Initial public release of the C++ version of LAMMPS. 52,967 lines of code in src dir. This version supersedes earlier versions, including LAMMPS 2001 (F90) and LAMMPS 99 (F77).