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lammps/doc/src/fix_manifoldforce.txt
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fix_manifoldforce.txt
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"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 manifoldforce command :h3
[Syntax:]
fix ID group-ID manifoldforce manifold manifold-args ... :pre
ID, group-ID are documented in "fix"_fix.html command :ulb,l
manifold = name of the manifold :l
manifold-args = parameters for the manifold :l
:ule
[Examples:]
fix constrain all manifoldforce sphere 5.0
[Description:]
This fix subtracts each time step from the force the component along the normal of the specified "manifold"_manifolds.html.
This can be used in combination with "minimize"_minimize.html to remove overlap between particles while
keeping them (roughly) constrained to the given manifold, e.g. to set up a run with "fix nve/manifold/rattle"_fix_nve_manifold_rattle.html.
I have found that only {hftn} and {quickmin} with a very small time step perform adequately though.
:line
[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. No global or per-atom quantities are stored
by this fix for access by various "output
commands"_Section_howto.html#howto_15. No parameter of this fix can
be used with the {start/stop} keywords of the "run"_run.html command.
This fix is invoked during "energy minimization"_minimize.html.
:line
[Restrictions:]
This fix is part of the USER-MANIFOLD package. It is only enabled if LAMMPS
was built with that package. See the "Making LAMMPS"_Section_start.html#start_3
section for more info.
Only use this with {min_style hftn} or {min_style quickmin}. If not, the constraints
will not be satisfied very well at all. A warning is generated if the {min_style} is
incompatible but no error.
:line
[Related commands:]
"fix nve/manifold/rattle"_fix_nve_manifold_rattle.html, "fix nvt/manifold/rattle"_fix_nvt_manifold_rattle.html
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