"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

create_box command :h3

[Syntax:]

create_box N region-ID :pre

N = # of atom types to use in this simulation
region-ID = ID of region to use as simulation domain :ul

[Examples:]

create_box 2 mybox :pre

[Description:]

This command creates a simulation box based on the specified region.
Thus a "region"_region.html command must first be used to define a
geometric domain.

The argument N is the number of atom types that will be used in the
simulation.

If the region is not of style {prism}, then LAMMPS encloses the region
(block, sphere, etc) with an axis-aligned (orthogonal) box which
becomes the simulation domain.

If the region is of style {prism}, LAMMPS creates a non-orthogonal
simulation domain shaped as a parallelepiped with triclinic symmetry.
See the "region prism"_region.html command for a description of how
the shape of the parallelepiped is defined.  The parallelepiped has
its "origin" at (xlo,ylo,zlo) and 3 edge vectors starting from its
origin given by a = (xhi-xlo,0,0); b = (xy,yhi-ylo,0); c =
(xz,yz,zhi-zlo).

A prism region used with the create_box command must have tilt factors
(xy,xz,yz) that do not skew the box more than half the distance of the
parallel box length.  For example, if xlo = 2 and xhi = 12, then the x
box length is 10 and the xy tilt factor must be between -5 and 5.
Similarly, both xz and yz must be between -(xhi-xlo)/2 and
+(yhi-ylo)/2.  Note that this is not a limitation, since if the
maximum tilt factor is 5 (as in this example), then configurations
with tilt = ..., -15, -5, 5, 15, 25, ... are all equivalent.

When a prism region is used, the simulation domain must be periodic in
any dimensions with a non-zero tilt factor, as defined by the
"boundary"_boundary.html command.  I.e. if the xy tilt factor is
non-zero, then both the x and y dimensions must be periodic.
Similarly, x and z must be periodic if xz is non-zero and y and z must
be periodic if yz is non-zero.

[Restrictions:]

An "atom_style"_atom_style.html and "region"_region.html must have
been previously defined to use this command.

[Related commands:]

"create_atoms"_create_atoms.html, "region"_region.html

[Default:] none
