"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)

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fix spring/self command :h3

[Syntax:]

fix ID group-ID spring/self K :pre

ID, group-ID are documented in "fix"_fix.html command
spring/self = style name of this fix command
K = spring constant (force/distance units) :ul

[Examples:]

fix tether boundary-atoms spring/self 10.0 :pre

[Description:]

Apply a spring force independently to each atom in the group to tether
it to its initial position.  The initial position for each atom is its
location at the time the fix command was issued.  At each timestep,
the magnitude of the force on each atom is -Kr, where r is the
displacement of the atom from its current position to its initial
position.

[Restart, fix_modify, output, run start/stop, minimize info:]

This fix writes the original coordinates of tethered atoms to "binary
restart files"_restart.html, so that the spring effect will be the
same 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 global scalar or vector or per-atom quantities are stored by
this fix for access by various "output
commands"_Section_howto.html#4_15.  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:]

"fix drag"_fix_drag.html, "fix spring"_fix_spring.html

[Default:] none
