LAMMPS WWW Site - LAMMPS Documentation - LAMMPS Commands

neighbor command

Syntax:

neighbor skin style 

Examples:

neighbor 0.3 bin
neighbor 2.0 nsq 

Description:

This command sets parameters that affect the building of the pairwise neighbor list. All atom pairs within a cutoff distance equal to the their force cutoff plus the skin distance are stored in the list. Typically, the larger the skin distance, the less often neighbor lists need to be built, but more pairs must be checked for possible force interactions every timestep.

The style value chooses what algorithm is used to build the list. Binning is an operation that scales linearly with N, the number of atoms on a processor. It is almost always faster than the nsq style which scales as N^2. For unsolvated small molecules in a non-periodic box, the nsq choice can sometimes be faster. Either style should give the same answers.

The default values for skin and style depend on the choice of units for the simulation.

The neigh_modify command has additional options that control how often neighbor lists are built and which pairs are stored in the list.

When a run is finished, counts of the number of neighbors stored in the pairwise list and the number of times neighbor lists were built are printed to the screen and log file. See this section for details.

Restrictions: none

Related commands:

neigh_modify, units

Default:

0.3 bin      for lj units
2.0 bin      for real or metal units