2009-12-22 08:34:36 +08:00
|
|
|
"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 store/force command :h3
|
|
|
|
|
|
|
|
[Syntax:]
|
|
|
|
|
|
|
|
fix ID group-ID store/force :pre
|
|
|
|
|
|
|
|
ID, group-ID are documented in "fix"_fix.html command
|
|
|
|
store/force = style name of this fix command :ul
|
|
|
|
|
|
|
|
[Examples:]
|
|
|
|
|
|
|
|
fix 1 all store/force :pre
|
|
|
|
|
|
|
|
[Description:]
|
|
|
|
|
2010-06-04 08:14:14 +08:00
|
|
|
Store the forces on atoms in the group at the point during each
|
|
|
|
timestep when the fix is invoked, as described below. This is useful
|
|
|
|
for storing forces before constraints or other boundary conditions are
|
|
|
|
computed which modify the forces, so that unmodified forces can be
|
|
|
|
"written to a dump file"_dump.html or accessed by other "output
|
2011-08-26 01:01:01 +08:00
|
|
|
commands"_Section_howto.html#howto_15 that use per-atom quantities.
|
2009-12-22 08:34:36 +08:00
|
|
|
|
|
|
|
This fix is invoked at the point in the velocity-Verlet timestepping
|
|
|
|
immediately after "pair"_pair_style.html, "bond"_bond_style.html,
|
|
|
|
"angle"_angle_style.html, "dihedral"_dihedral_style.html,
|
|
|
|
"improper"_improper_style.html, and "long-range"_kspace_style.html
|
|
|
|
forces have been calculated. It is the point in the timestep when
|
|
|
|
various fixes that compute constraint forces are calculated and
|
|
|
|
potentially modify the force on each atom. Examples of such fixes are
|
|
|
|
"fix shake"_fix_shake.html, "fix wall"_fix_wall.html, and "fix
|
|
|
|
indent"_fix_indent.html.
|
|
|
|
|
|
|
|
IMPORTANT NOTE: The order in which various fixes are applied which
|
|
|
|
operate at the same point during the timestep, is the same as the
|
|
|
|
order they are specified in the input script. Thus normally, if you
|
|
|
|
want to store per-atom forces due to force field interactions, before
|
|
|
|
constraints are applied, you should list this fix first within that
|
|
|
|
set of fixes, i.e. before other fixes that apply constraints.
|
|
|
|
However, if you wish to include certain constraints (e.g. fix shake)
|
|
|
|
in the stored force, then it could be specified after some fixes and
|
|
|
|
before others.
|
|
|
|
|
|
|
|
[Restart, fix_modify, output, run start/stop, minimize info:]
|
|
|
|
|
|
|
|
No information about this fix is written to "binary restart
|
|
|
|
files"_restart.html. None of the "fix_modify"_fix_modify.html options
|
|
|
|
are relevant to this fix.
|
|
|
|
|
|
|
|
This fix produces a per-atom array which can be accessed by various
|
2011-08-26 01:01:01 +08:00
|
|
|
"output commands"_Section_howto.html#howto_15. The number of columns
|
|
|
|
for each atom is 3, and the columns store the x,y,z forces on each
|
|
|
|
atom. The per-atom values be accessed on any timestep.
|
2009-12-22 08:34:36 +08:00
|
|
|
|
|
|
|
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:]
|
|
|
|
|
2010-06-04 08:37:28 +08:00
|
|
|
"fix store_state"_fix_store_state.html
|
2009-12-22 08:34:36 +08:00
|
|
|
|
|
|
|
[Default:] none
|