forked from lijiext/lammps
82 lines
2.9 KiB
Plaintext
82 lines
2.9 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 pair command :h3
|
|
|
|
[Syntax:]
|
|
|
|
compute ID group-ID pair pstyle evalue :pre
|
|
|
|
ID, group-ID are documented in "compute"_compute.html command
|
|
pair = style name of this compute command
|
|
pstyle = style name of a pair style that calculates additional values
|
|
evalue = {epair} or {evdwl} or {ecoul} or blank (optional setting) :ul
|
|
|
|
[Examples:]
|
|
|
|
compute 1 all pair gauss
|
|
compute 1 all pair lj/cut/coul/cut ecoul
|
|
compute 1 all pair reax :pre
|
|
|
|
[Description:]
|
|
|
|
Define a computation that extracts additional values calculated by a
|
|
pair style, sums them across processors, and makes them accessible for
|
|
output or further processing by other commands. The group specified
|
|
for this command is ignored.
|
|
|
|
The specified {pstyle} must be a pair style used in your simulation
|
|
either by itself or as a sub-style in a "pair_style hybrid or
|
|
hybrid/overlay"_pair_hybrid.html command.
|
|
|
|
The {evalue} setting is optional; it may be left off the command. All
|
|
pair styles tally a potential energy {epair} which may be broken into
|
|
two parts: {evdwl} and {ecoul} such that {epair} = {evdwl} + {ecoul}.
|
|
If the pair style calculates Coulombic interactions, their energy will
|
|
be tallied in {ecoul}. Everything else (whether it is a Lennard-Jones
|
|
style van der Waals interaction or not) is tallied in {evdwl}. If
|
|
{evalue} is specified as {epair} or left out, then {epair} is stored
|
|
as a global scalar by this compute. This is useful when using
|
|
"pair_style hybrid"_pair_hybrid.html if you want to know the portion
|
|
of the total energy contributed by one sub-style. If {evalue} is
|
|
specfied as {evdwl} or {ecoul}, then just that portion of the energy
|
|
is stored as a global scalar.
|
|
|
|
Some pair styles tally additional quantities, e.g. a breakdown of
|
|
potential energy into a dozen or so components is tallied by the
|
|
"pair_style reax"_pair_reax.html commmand. These values (1 or more)
|
|
are stored as a global vector by this compute. See the doc page for
|
|
"individual pair styles"_pair_style.html for info on these values.
|
|
|
|
[Output info:]
|
|
|
|
This compute calculates a global scalar which is {epair} or {evdwl} or
|
|
{ecoul}. If the pair style supports it, it also calculates a global
|
|
vector of length >= 1, as determined by the pair style. These values
|
|
can be used by any command that uses global scalar or vector values
|
|
from a compute as input. See "this
|
|
section"_Section_howto.html#howto_15 for an overview of LAMMPS output
|
|
options.
|
|
|
|
The scalar and vector values calculated by this compute are
|
|
"extensive".
|
|
|
|
The scalar value will be in energy "units"_units.html. The vector
|
|
values will typically also be in energy "units"_units.html, but
|
|
see the doc page for the pair style for details.
|
|
|
|
[Restrictions:] none
|
|
|
|
[Related commands:]
|
|
|
|
"compute pe"_compute_pe.html
|
|
|
|
[Default:]
|
|
|
|
The default for {evalue} is {epair}.
|