forked from lijiext/lammps
64 lines
1.8 KiB
Plaintext
64 lines
1.8 KiB
Plaintext
.. index:: fix nve/noforce
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fix nve/noforce 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 nve
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* ID, group-ID are documented in :doc:`fix <fix>` command
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* nve/noforce = style name of this fix command
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Examples
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""""""""
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.. parsed-literal::
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fix 3 wall nve/noforce
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Description
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"""""""""""
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Perform updates of position, but not velocity for atoms in the group
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each timestep. In other words, the force on the atoms is ignored and
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their velocity is not updated. The atom velocities are used to update
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their positions.
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This can be useful for wall atoms, when you set their velocities, and
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want the wall to move (or stay stationary) in a prescribed fashion.
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This can also be accomplished via the :doc:`fix setforce <fix_setforce>`
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command, but with fix nve/noforce, the forces on the wall atoms are
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unchanged, and can thus be printed by the :doc:`dump <dump>` command or
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queried with an equal-style :doc:`variable <variable>` that uses the
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fcm() group function to compute the total force on the group of atoms.
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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 :ref:`output commands <howto_15>`. No parameter of this fix can
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be used with the *start/stop* keywords of the :doc:`run <run>` command.
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This fix is not invoked during :doc:`energy minimization <minimize>`.
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Restrictions
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""""""""""""
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none
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Related commands
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""""""""""""""""
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:doc:`fix nve <fix_nve>`
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**Default:** none
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.. _lws: http://lammps.sandia.gov
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.. _ld: Manual.html
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.. _lc: Section_commands.html#comm
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