"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Commands_all.html)

:line

reset_ids command :h3

[Syntax:]

reset_ids :pre

[Examples:]

reset_ids :pre

[Description:]

Reset atom IDs for the system, including all the global IDs stored
for bond, angle, dihedral, improper topology data.  This will
create a set of IDs that are numbered contiguously from 1 to N
for a N atoms system.

This can be useful to do after performing a "delete_atoms" command for
a molecular system.  The delete_atoms compress yes option will not
perform this operation due to the existence of bond topology.  It can
also be useful to do after any simulation which has lost atoms,
e.g. due to atoms moving outside a simulation box with fixed
boundaries (see the "boundary command"), or due to evaporation (see
the "fix evaporate" command).

Note that the resetting of IDs is not really a compression, where gaps
in atom IDs are removed by decrementing atom IDs that are larger.
Instead the IDs for all atoms are erased, and new IDs are assigned so
that the atoms owned by an individual processor have consecutive IDs,
as the "create_atoms"_create_atoms.html command explains.

NOTE: If this command is used before a "pair style"_pair_style.html is
defined, an error about bond topology atom IDs not being found may
result.  This is because the cutoff distance for ghost atom
communication was not sufficient to find atoms in bonds, angles, etc
that are owned by other processors.  The "comm_modify
cutoff"_comm_modify.html command can be used to correct this issue.
Or you can define a pair style before using this command.  If you do
the former, you should unset the comm_modify cutoff after using
reset_ids so that subsequent communication is not inefficient.

[Restrictions:] none

[Related commands:]

"delete_atoms"_delete_atoms.html

[Default:] none
