forked from lijiext/lammps
111 lines
3.6 KiB
Plaintext
111 lines
3.6 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
|
|
|
|
pair_style lj/expand command :h3
|
|
pair_style lj/expand/cuda command :h3
|
|
pair_style lj/expand/gpu command :h3
|
|
|
|
[Syntax:]
|
|
|
|
pair_style lj/expand cutoff :pre
|
|
|
|
cutoff = global cutoff for lj/expand interactions (distance units) :ul
|
|
|
|
[Examples:]
|
|
|
|
pair_style lj/expand 2.5
|
|
pair_coeff * * 1.0 1.0 0.5
|
|
pair_coeff 1 1 1.0 1.0 -0.2 2.0 :pre
|
|
|
|
[Description:]
|
|
|
|
Style {lj/expand} computes a LJ interaction with a distance shifted by
|
|
delta which can be useful when particles are of different sizes, since
|
|
it is different that using different sigma values in a standard LJ
|
|
formula:
|
|
|
|
:c,image(Eqs/pair_lj_expand.jpg)
|
|
|
|
Rc is the cutoff which does not include the delta distance. I.e. the
|
|
actual force cutoff is the sum of cutoff + delta.
|
|
|
|
The following coefficients must be defined for each pair of atoms
|
|
types via the "pair_coeff"_pair_coeff.html command as in the examples
|
|
above, or in the data file or restart files read by the
|
|
"read_data"_read_data.html or "read_restart"_read_restart.html
|
|
commands, or by mixing as described below:
|
|
|
|
epsilon (energy units)
|
|
sigma (distance units)
|
|
delta (distance units)
|
|
cutoff (distance units) :ul
|
|
|
|
The delta values can be positive or negative. The last coefficient is
|
|
optional. If not specified, the global LJ cutoff is used.
|
|
|
|
:line
|
|
|
|
Styles with a {cuda}, {gpu}, or {opt} suffix are functionally the same
|
|
as the corresponding style without the suffix. They have been
|
|
optimized to run faster, depending on your available hardware, as
|
|
discussed in "this section"_Section_accelerate.html of the manual.
|
|
The accelerated styles take the same arguments and should produce the
|
|
same results, except for round-off and precision issues.
|
|
|
|
These accelerated styles are part of the "user-cuda", "gpu", and "opt"
|
|
packages respectively. They are only enabled if LAMMPS was built with
|
|
those packages. See the "Making LAMMPS"_Section_start.html#2_3
|
|
section for more info.
|
|
|
|
You can specify the accelerated styles explicitly in your input script
|
|
by including their suffix, or you can use the "-suffix command-line
|
|
switch"_Section_start.html#2_6 when you invoke LAMMPS, or you can use
|
|
the "suffix"_suffix.html command in your input script.
|
|
|
|
See "this section"_Section_accelerate.html of the manual for more
|
|
instructions on how to use the accelerated styles effectively.
|
|
|
|
:line
|
|
|
|
[Mixing, shift, table, tail correction, restart, rRESPA info]:
|
|
|
|
For atom type pairs I,J and I != J, the epsilon, sigma, and shift
|
|
coefficients and cutoff distance for this pair style can be mixed.
|
|
Shift is always mixed via an {arithmetic} rule. The other
|
|
coefficients are mixed according to the pair_modify mix value. The
|
|
default mix value is {geometric}. See the "pair_modify" command for
|
|
details.
|
|
|
|
This pair style supports the "pair_modify"_pair_modify.html shift
|
|
option for the energy of the pair interaction.
|
|
|
|
The "pair_modify"_pair_modify.html table option is not relevant
|
|
for this pair style.
|
|
|
|
This pair style supports the "pair_modify"_pair_modify.html tail
|
|
option for adding a long-range tail correction to the energy and
|
|
pressure of the pair interaction.
|
|
|
|
This pair style writes its information to "binary restart
|
|
files"_restart.html, so pair_style and pair_coeff commands do not need
|
|
to be specified in an input script that reads a restart file.
|
|
|
|
This pair style can only be used via the {pair} keyword of the
|
|
"run_style respa"_run_style.html command. It does not support the
|
|
{inner}, {middle}, {outer} keywords.
|
|
|
|
:line
|
|
|
|
[Restrictions:] none
|
|
|
|
[Related commands:]
|
|
|
|
"pair_coeff"_pair_coeff.html
|
|
|
|
[Default:] none
|