forked from lijiext/lammps
60 lines
1.8 KiB
Plaintext
60 lines
1.8 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
|
|
|
|
fix msd command :h3
|
|
|
|
[Syntax:]
|
|
|
|
fix ID group-ID msd N file :pre
|
|
|
|
ID, group-ID are documented in "fix"_fix.html command
|
|
msd = style name of this fix command
|
|
N = compute mean-squared displacement every this many timesteps
|
|
file = filename to write mean-squared displacement info to :ul
|
|
|
|
[Examples:]
|
|
|
|
fix 1 all msd 100 diff.out :pre
|
|
|
|
[Description:]
|
|
|
|
Compute the mean-squared displacement of the group of atoms every N
|
|
steps, including all effects due to atoms passing thru periodic
|
|
boundaries. The slope of the mean-squared displacement versus time is
|
|
proportional to the diffusion coefficient of the diffusing atoms. The
|
|
"origin" of the displacement for each atom is its position at the time
|
|
the fix command was issued. Write the results to the specified file.
|
|
|
|
[Restart, fix_modify, thermo output, run start/stop, minimize info:]
|
|
|
|
This fix writes the original coordinates of diffusing atoms to "binary
|
|
restart files"_restart.html, so that the mean-squared displacement
|
|
will be accurate in a restarted simulation. See the
|
|
"read_restart"_read_restart.html command for info on how to re-specify
|
|
a fix in an input script that reads a restart file, so that the
|
|
operation of the fix continues in an uninterrupted fashion.
|
|
|
|
None of the "fix_modify"_fix_modify.html options are relevant to this
|
|
fix. No quantities calculated by this fix can be output by the
|
|
"thermo_style custom"_thermo_style.html command. No parameter of this
|
|
fix can be used with the {start/stop} keywords of the "run"_run.html
|
|
command. This fix is not invoked during "energy
|
|
minimization"_minimize.html.
|
|
|
|
[Restrictions:] none
|
|
|
|
[Related commands:] none
|
|
|
|
[Default:] none
|
|
|
|
|
|
|
|
|
|
|
|
|