pair_style tracker command


pair_style tracker keyword
  • zero or more keyword/arg pairs may be appended

  • keyword = finite

    finite value = none
       pair style uses atomic diameters to identify contacts


pair_style hybrid/overlay tracker ...
pair_coeff 1 1 tracker 2.0

pair_style hybrid/overlay tracker finite ...
pair_coeff * * tracker

fix 1 all pair/tracker 1000 time/created time/broken
dump 1 all local 1000 dump.local f_1[1] f_1[2]
dump_modify 1 write_header no


Style tracker monitors information about pairwise interactions. It does not calculate any forces on atoms. Pair hybrid/overlay can be used to combine this pair style with another pair style. Style tracker must be used in conjunction with about fix pair_tracker which contains information on what data can be output.

If the finite keyword is not defined, the following coefficients must be defined for each pair of atom types via the pair_coeff command as in the examples above, or in the data file or restart files read by the read_data or read_restart commands, or by mixing as described below:

  • cutoff (distance units)

If the finite keyword is defined, no coefficients may be defined. Interaction cutoffs are alternatively calculated based on the diameter of finite particles.

Mixing, shift, table, tail correction, restart, rRESPA info

For atom type pairs I,J and I != J, the cutoff coefficient and cutoff distance for this pair style can be mixed. The cutoff is always mixed via a geometric rule. The cutoff is mixed according to the pair_modify mix value. The default mix value is geometric. See the “pair_modify” command for details.

This pair style writes its information to binary restart files, so pair_style and pair_coeff commands do not need to be specified in an input script that reads a restart file.

The pair_modify shift, table, and tail options are not relevant for this pair style.


A corresponding fix pair_tracker must be defined to use this pair style.

This pair style is currently incompatible with granular pair styles that extend beyond the contact (e.g. JKR and DMT).

This fix is part of the MISC package. It is only enabled if LAMMPS was built with that package. See the Build package page for more info.