73 lines
2.1 KiB
Plaintext
73 lines
2.1 KiB
Plaintext
.. index:: fix manifoldforce
|
|
|
|
fix manifoldforce command
|
|
=========================
|
|
|
|
Syntax
|
|
""""""
|
|
|
|
.. parsed-literal::
|
|
|
|
fix ID group-ID manifoldforce manifold manifold-args ...
|
|
|
|
* ID, group-ID are documented in :doc:`fix <fix>` command
|
|
* manifold = name of the manifold
|
|
* manifold-args = parameters for the manifold
|
|
|
|
|
|
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 :doc:`manifold <manifolds>`.
|
|
This can be used in combination with :doc:`minimize <minimize>` to remove overlap between particles while
|
|
keeping them (roughly) constrained to the given manifold, e.g. to set up a run with :doc:`fix nve/manifold/rattle <fix_nve_manifold_rattle>`.
|
|
I have found that only *hftn* and *quickmin* with a very small time step perform adequately though.
|
|
|
|
|
|
----------
|
|
|
|
|
|
Restart, fix_modify, output, run start/stop, minimize info
|
|
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
|
|
|
|
No information about this fix is written to :doc:`binary restart files <restart>`. None of the :doc:`fix_modify <fix_modify>` options
|
|
are relevant to this fix. No global or per-atom quantities are stored
|
|
by this fix for access by various :ref:`output commands <howto_15>`. No parameter of this fix can
|
|
be used with the *start/stop* keywords of the :doc:`run <run>` command.
|
|
This fix is invoked during :doc:`energy minimization <minimize>`.
|
|
|
|
|
|
----------
|
|
|
|
|
|
Restrictions
|
|
""""""""""""
|
|
|
|
|
|
This fix is part of the USER-MANIFOLD package. It is only enabled if LAMMPS
|
|
was built with that package. See the :ref:`Making LAMMPS <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.
|
|
|
|
|
|
----------
|
|
|
|
|
|
Related commands
|
|
""""""""""""""""
|
|
|
|
:doc:`fix nve/manifold/rattle <fix_nve_manifold_rattle>`, :doc:`fix nvt/manifold/rattle <fix_nvt_manifold_rattle>`
|
|
|
|
|
|
.. _lws: http://lammps.sandia.gov
|
|
.. _ld: Manual.html
|
|
.. _lc: Section_commands.html#comm
|