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5. Example problems

The LAMMPS distribution includes an examples sub-directory with several sample problems. Each problem is in a sub-directory of its own. Most are 2d models so that they run quickly, requiring at most a couple of minutes to run on a desktop machine. Each problem has an input script (in.*) and produces a log file (log.*) and dump file (dump.*) when it runs. Some use a data file (data.*) of initial coordinates as additional input. A few sample log file outputs on different machines and different numbers of processors are included in the directories to compare your answers to. E.g. a log file like log.crack.foo.P means it ran on P processors of machine "foo".

The dump files produced by the example runs can be animated using the xmovie tool described in the Tools section. MPEG versions of most of the xmovie animations are also viewable from the Examples page of the LAMMPS WWW Site.

These are the sample problems in the examples sub-directories:

flow Couette and Poisseuille flow in a 2d channel
indent spherical indenter into a 2d solid
micelle self-assembly of small lipid-like molecules into 2d bilayers
obstacle flow around two voids in a 2d channel
pour pouring of granular particles into a 3d box, then chute flow
crack crack propagation in a 2d solid
friction frictional contact of spherical asperities between 2d surfaces
melt rapid melt of 3d LJ system
peptide dynamics of a small solvated peptide chain (5-mer)
shear sideways shear applied to 2d solid, with and without a void

Here is how you might run and visualize one of the sample problems:

cd indent
cp ../../src/lmp_linux .           # copy LAMMPS executable to this dir
lmp_linux < in.indent              # run the problem 

Running the simulation produces the files dump.indent and log.lammps. You can visualize the dump file as follows:

../../tools/xmovie/xmovie -scale dump.indent