forked from lijiext/lammps
61 lines
1.8 KiB
Plaintext
61 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 setforce command :h3
|
|
|
|
[Syntax:]
|
|
|
|
fix ID group-ID setforce fx fy fz :pre
|
|
|
|
ID, group-ID are documented in "fix"_fix.html command
|
|
setforce = style name of this fix command
|
|
fx,fy,fz = force component values :ul
|
|
|
|
[Examples:]
|
|
|
|
fix freeze indenter setforce 0.0 0.0 0.0
|
|
fix 2 edge setforce NULL 0.0 0.0 :pre
|
|
|
|
[Description:]
|
|
|
|
Set each component of force on each atom in the group to the specified
|
|
values fx,fy,fz. This erases all previously computed forces on the
|
|
atom, though additional fixes could add new forces. This command can
|
|
be used to freeze certain atoms in the simulation by zeroing their
|
|
force, assuming their initial velocity zero.
|
|
|
|
Any of the fx,fy,fz values can be specified as NULL which means do not
|
|
alter the force component in that dimension.
|
|
|
|
[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 computes a 3-vector of forces, which can be accessed by
|
|
various "output commands"_Section_howto.html#4_15. This is the total
|
|
force on the group of atoms before the forces on individual atoms are
|
|
reset by the fix. The vector values calculated by this fix are
|
|
"extensive", meaning they scale with the number of atoms in the
|
|
simulation.
|
|
|
|
No parameter of this fix can be used with the {start/stop} keywords of
|
|
the "run"_run.html command.
|
|
|
|
The forces due to this fix are imposed during an energy minimization,
|
|
invoked by the "minimize"_minimize.html command.
|
|
|
|
[Restrictions:] none
|
|
|
|
[Related commands:]
|
|
|
|
"fix addforce"_fix_addforce.html, "fix aveforce"_fix_aveforce.html
|
|
|
|
[Default:] none
|