LIGGGHTS Users Manual
Author: http://lammps.sandia.gov - Sandia National Laboratories

LIGGGHTS WWW Site - LAMMPS WWW Site - LIGGGHTS Documentation - LIGGGHTS Commands

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### LIGGGHTS Documentation, Version 3.X

LIGGGHTS stands for LAMMPS Improved for General Granular and Granular Heat Transfer Simulations. It is part of the CFDEMproject, www.cfdem.com

The core developers of LIGGGHTS are Christoph Kloss (DCS Computing GmbH, Linz and JKU Linz) and Richard Berger (JKU Linz), with major contributions from Philippe Seil, Andreas Aigner and Stefan Amberger (all JKU Linz) and Christoph Goniva (DCS Computing GmbH, Linz and JKU Linz)

CFDEMproject has more information about the code and its uses. For questions about the code, please use the forums at CFDEMproject.

LIGGGHTS is based on LAMMPS (see below), and so is its manual. So if the manual says 'LAMMPS', you could read 'LIGGGHTS' instead. However, we want to make clear which parts of the code and framework stem from the LAMMPS base.

#### LIGGGHTS Version info:

All LIGGGHTS versions are based on a specific version of LAMMPS, as printed in the file src/version.h LIGGGHTS version are identidied by a version number (e.g. '3.0'), a branch name (e.g. 'LIGGGHTS-PUBLIC' for the public release of LIGGGHTS), compilation info (date / time stamp and user name), and a LAMMPS version number (which is the LAMMPS version that the LIGGGHTS release is based on). For info on the LAMMPS version, see below.

#### LAMMPS Version info:

The LAMMPS "version" is the date when it was released, such as 1 May 2010. LAMMPS is updated continuously. Whenever we fix a bug or add a feature, we release it immediately, and post a notice on this page of the WWW site. Each dated copy of LAMMPS contains all the features and bug-fixes up to and including that version date. The version date is printed to the screen and logfile every time you run LAMMPS. It is also in the file src/version.h and in the LAMMPS directory name created when you unpack a tarball, and at the top of the first page of the manual (this page).

- If you browse the HTML doc pages on the LAMMPS WWW site, they always describe the most current version of LAMMPS.
- If you browse the HTML doc pages included in your tarball, they describe the version you have.
- The PDF file on the WWW site or in the tarball is updated about once per month. This is because it is large, and we don't want it to be part of every patch.
- There is also a Developer.pdf file in the doc directory, which describes the internal structure and algorithms of LAMMPS.

LAMMPS stands for Large-scale Atomic/Molecular Massively Parallel Simulator.

LAMMPS is 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).

The primary developers of LAMMPS are Steve Plimpton, Aidan Thompson, and Paul Crozier who can be contacted at sjplimp,athomps,pscrozi at sandia.gov. The LAMMPS WWW Site at http://lammps.sandia.gov has more information about the code and its uses.

The LAMMPS documentation is organized into the following sections. If you find errors or omissions in this manual or have suggestions for useful information to add, please send an email to the developers so we can improve the LAMMPS documentation.

Once you are familiar with LAMMPS, you may want to bookmark this page at Section_commands.html#comm since it gives quick access to documentation for all LAMMPS commands.

PDF file of the entire manual, generated by htmldoc

1. Introduction
   1.1 What is LAMMPS
   1.2 LAMMPS features
   1.3 LAMMPS non-features
   1.4 Open source distribution
   1.5 Acknowledgments and citations
2. Getting started
   2.1 What's in the LAMMPS distribution
   2.2 Making LAMMPS
   2.3 Making LAMMPS with optional packages
   2.4 Building LAMMPS via the Make.py script
   2.5 Building LAMMPS as a library
   2.6 Running LAMMPS
   2.7 Command-line options
   2.8 Screen output
   2.9 Tips for users of previous versions
3. Commands
   3.1 LAMMPS input script
   3.2 Parsing rules
   3.3 Input script structure
   3.4 Commands listed by category
   3.5 Commands listed alphabetically
4. Packages
   4.1 Standard packages
   4.2 User packages
5. Accelerating LAMMPS performance
   5.1 Measuring performance
   5.2 General strategies
   5.3 Packages with optimized styles
   5.4 OPT package
   5.5 USER-OMP package
   5.6 GPU package
   5.7 USER-CUDA package
   5.8 Comparison of GPU and USER-CUDA packages
6. How-to discussions
   6.1 Restarting a simulation
   6.2 2d simulations
   6.3 CHARMM and AMBER force fields
   6.4 Running multiple simulations from one input script
   6.5 Multi-replica simulations
   6.6 Granular models
   6.7 TIP3P water model
   6.8 TIP4P water model
   6.9 SPC water model
   6.10 Coupling LAMMPS to other codes
   6.11 Visualizing LAMMPS snapshots
   6.12 Triclinic (non-orthogonal) simulation boxes
   6.13 NEMD simulations
   6.14 Finite-size spherical and aspherical particles
   6.15 Output from LAMMPS (thermo, dumps, computes, fixes, variables)
   6.16 Thermostatting, barostatting, and compute temperature
   6.17 Walls
   6.18 Elastic constants
   6.19 Library interface to LAMMPS
   6.20 Calculating thermal conductivity
   6.21 Calculating viscosity
7. Example problems
8. Performance & scalability
9. Additional tools
10. Modifying & extending LAMMPS
    10.1 Atom styles
    10.2 Bond, angle, dihedral, improper potentials
    10.3 Compute styles
    10.4 Dump styles
    10.5 Dump custom output options
    10.6 Fix styles
    10.7 Input script commands
    10.8 Kspace computations
    10.9 Minimization styles
    10.10 Pairwise potentials
    10.11 Region styles
    10.12 Body styles
    10.13 Thermodynamic output options
    10.14 Variable options
    10.15 Submitting new features for inclusion in LAMMPS
11. Python interface
    11.1 Building LAMMPS as a shared library
    11.2 Installing the Python wrapper into Python
    11.3 Extending Python with MPI to run in parallel
    11.4 Testing the Python-LAMMPS interface
    11.5 Using LAMMPS from Python
    11.6 Example Python scripts that use LAMMPS
12. Errors
    12.1 Common problems
    12.2 Reporting bugs
    12.3 Error & warning messages
13. Future and history
    13.1 Coming attractions
    13.2 Past versions