lammps/doc/replicate.txt

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"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)
:line
replicate command :h3
[Syntax:]
replicate nx ny nz :pre
nx,ny,nz = replication factors in each dimension :ul
[Examples:]
replicate 2 3 2 :pre
[Description:]
Replicate the current simulation one or more times in each dimension.
For example, replication factors of 2,2,2 will create a simulation
with 8x as many atoms by doubling the simulation domain in each
dimension. A replication factor of 1 in a dimension leaves the
simulation domain unchanged.
All properties of the atoms are replicated, including their
velocities, which may or may not be desirable. New atom IDs (tags)
are assigned to new atoms, as are molecule IDs. Bonds and other
topology interactions are created between pairs of new atoms as well
as between old and new atoms. This is done by using the image flag
for each atom to "unwrap" it out of the periodic box before
replicating it. This means that molecular bonds you specify in the
original data file that span the periodic box should be between two
atoms with image flags that differ by 1. This will allow them to be
unwrapped appropriately.
This command operates similar to the replicate tool in the tools
sub-directory of the LAMMPS distribution which creates new data files
from old ones.
[Restrictions:]
A 2d simulation cannot be replicated in the z dimension.
If a simulation is non-periodic in a dimension, care should be used
when replicating it in that dimension, as it may put atoms nearly on
top of each other.
If the current simulation was read in from a restart file (before a
run is performed), there can have been no fix information stored in
the file for individual atoms. Similarly, no fixes can be defined at
the time the replicate command is used that require vectors of atom
information to be stored. This is because the replicate command does
not know how to replicate that information for new atoms it creates.
Replicating a system that has rigid bodies (defined via the "fix
rigid"_fix_rigid.html command), either currently defined or that
created the restart file which was read in before replicating, can
cause problems if there is a bond between a pair of rigid bodies that
straddle a periodic boundary. This is because the periodic image
information for particles in the rigid bodies are set differently than
for a non-rigid system and can result in a new bond being created that
spans the periodic box. Thus you cannot use the replicate command in
this scenario.
[Related commands:] none
[Default:] none