"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Commands_all.html)

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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"_Howto_manifold.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.

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[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"_Howto_output.html.
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.

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[Restrictions:]

This fix is part of the USER-MANIFOLD package. It is only enabled if
LAMMPS was built with that package.  See the "Build
package"_Build_package.html doc page 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.

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[Related commands:]

"fix nve/manifold/rattle"_fix_nve_manifold_rattle.html, "fix
nvt/manifold/rattle"_fix_nvt_manifold_rattle.html

