66 lines
1.8 KiB
ReStructuredText
66 lines
1.8 KiB
ReStructuredText
.. index:: fix oneway
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fix oneway command
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==================
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Syntax
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""""""
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.. parsed-literal::
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fix ID group-ID oneway N region-ID direction
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* ID, group-ID are documented in :doc:`fix <fix>` command
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* oneway = style name of this fix command
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* N = apply this fix every this many timesteps
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* region-ID = ID of region where fix is active
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* direction = *x* or *-x* or *y* or *-y* or *z* or *-z* = coordinate and direction of the oneway constraint
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Examples
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""""""""
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.. code-block:: LAMMPS
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fix ions oneway 10 semi -x
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fix all oneway 1 left -z
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fix all oneway 1 right z
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Description
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"""""""""""
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Enforce that particles in the group and in a given region can only
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move in one direction. This is done by reversing a particle's
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velocity component, if it has the wrong sign in the specified
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dimension. The effect is that the particle moves in one direction
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only.
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This can be used, for example, as a simple model of a semi-permeable
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membrane, or as an implementation of Maxwell's demon.
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----------
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Restart, fix_modify, output, run start/stop, minimize info
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"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
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No information about this fix is written to :doc:`binary restart files <restart>`. None of the :doc:`fix_modify <fix_modify>` options
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are relevant to this fix. No global or per-atom quantities are stored
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by this fix for access by various :doc:`output commands <Howto_output>`.
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No parameter of this fix can be used with the *start/stop* keywords of
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the :doc:`run <run>` command. This fix is not invoked during :doc:`energy minimization <minimize>`.
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Restrictions
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""""""""""""
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This fix is part of the MISC package. It is only enabled if LAMMPS
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was built with that package. See the :doc:`Build package <Build_package>` page for more info.
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Related commands
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""""""""""""""""
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:doc:`fix wall/reflect <fix_wall_reflect>` command
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Default
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"""""""
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none
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