forked from lijiext/lammps
80 lines
2.8 KiB
Plaintext
80 lines
2.8 KiB
Plaintext
"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
|
|
|
|
compute coord/atom command :h3
|
|
|
|
[Syntax:]
|
|
|
|
compute ID group-ID coord/atom cutoff type1 type2 ... :pre
|
|
|
|
ID, group-ID are documented in "compute"_compute.html command
|
|
coord/atom = style name of this compute command
|
|
cutoff = distance within which to count coordination neighbors (distance units)
|
|
typeN = atom type for Nth coordination count (see asterisk form below) :ul
|
|
|
|
[Examples:]
|
|
|
|
compute 1 all coord/atom 2.0
|
|
compute 1 all coord/atom 6.0 1 2
|
|
compute 1 all coord/atom 6.0 2*4 5*8 * :pre
|
|
|
|
[Description:]
|
|
|
|
Define a computation that calculates one or more coordination numbers
|
|
for each atom in a group.
|
|
|
|
A coordination number is defined as the number of neighbor atoms with
|
|
specified atom type(s) that are within the specified cutoff distance
|
|
from the central atom. Atoms not in the group are included in a
|
|
coordination number of atoms in the group.
|
|
|
|
The {typeN} keywords allow you to specify which atom types contribute
|
|
to each coordination number. One coordination number is computed for
|
|
each of the {typeN} keywords listed. If no {typeN} keywords are
|
|
listed, a single coordination number is calculated, which includes
|
|
atoms of all types (same as the "*" format, see below).
|
|
|
|
The {typeN} keywords can be specified in one of two ways. An explicit
|
|
numeric value can be used, as in the 2nd example above. Or a
|
|
wild-card asterisk can be used to specify a range of atom types. This
|
|
takes the form "*" or "*n" or "n*" or "m*n". If N = the number of
|
|
atom types, then an asterisk with no numeric values means all types
|
|
from 1 to N. A leading asterisk means all types from 1 to n
|
|
(inclusive). A trailing asterisk means all types from n to N
|
|
(inclusive). A middle asterisk means all types from m to n
|
|
(inclusive).
|
|
|
|
The value of all coordination numbers will be 0.0 for atoms not in the
|
|
specified compute group.
|
|
|
|
The neighbor list needed to compute this quantity is constructed each
|
|
time the calculation is performed (i.e. each time a snapshot of atoms
|
|
is dumped). Thus it can be inefficient to compute/dump this quantity
|
|
too frequently.
|
|
|
|
[Output info:]
|
|
|
|
If single {type1} keyword is specified (or if none are specified),
|
|
this compute calculates a per-atom vector. If multiple {typeN}
|
|
keywords are specified, this compute calculates a per-atom array, with
|
|
N columns. These values can be accessed by any command that uses
|
|
per-atom values from a compute as input. See "Section_howto
|
|
15"_Section_howto.html#howto_15 for an overview of LAMMPS output
|
|
options.
|
|
|
|
The per-atom vector or array values will be a number >= 0.0, as
|
|
explained above.
|
|
|
|
[Restrictions:] none
|
|
|
|
[Related commands:]
|
|
|
|
"compute cluster/atom"_compute_cluster_atom.html
|
|
|
|
[Default:] none
|