forked from lijiext/lammps
112 lines
3.6 KiB
Plaintext
112 lines
3.6 KiB
Plaintext
.. index:: fix nve/sphere
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fix nve/sphere command
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======================
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fix nve/sphere/omp 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/sphere
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* ID, group-ID are documented in :doc:`fix <fix>` command
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* nve/sphere = style name of this fix command
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* zero or more keyword/value pairs may be appended
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* keyword = *update*
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.. parsed-literal::
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*update* value = *dipole*
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dipole = update orientation of dipole moment during integration
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Examples
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""""""""
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.. parsed-literal::
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fix 1 all nve/sphere
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fix 1 all nve/sphere update dipole
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Description
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"""""""""""
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Perform constant NVE integration to update position, velocity, and
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angular velocity for finite-size spherical particles in the group each
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timestep. V is volume; E is energy. This creates a system trajectory
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consistent with the microcanonical ensemble.
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This fix differs from the :doc:`fix nve <fix_nve>` command, which
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assumes point particles and only updates their position and velocity.
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If the *update* keyword is used with the *dipole* value, then the
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orientation of the dipole moment of each particle is also updated
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during the time integration. This option should be used for models
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where a dipole moment is assigned to finite-size particles,
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e.g. spheroids via use of the :doc:`atom_style hybrid sphere dipole <atom_style>` command.
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----------
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Styles with a *gpu*\ , *intel*\ , *kk*\ , *omp*\ , or *opt* suffix are
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functionally the same as the corresponding style without the suffix.
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They have been optimized to run faster, depending on your available
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hardware, as discussed in :doc:`Section_accelerate <Section_accelerate>`
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of the manual. The accelerated styles take the same arguments and
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should produce the same results, except for round-off and precision
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issues.
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These accelerated styles are part of the GPU, USER-INTEL, KOKKOS,
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USER-OMP and OPT packages, respectively. They are only enabled if
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LAMMPS was built with those packages. See the :ref:`Making LAMMPS <start_3>` section for more info.
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You can specify the accelerated styles explicitly in your input script
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by including their suffix, or you can use the :ref:`-suffix command-line switch <start_7>` when you invoke LAMMPS, or you can
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use the :doc:`suffix <suffix>` command in your input script.
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See :doc:`Section_accelerate <Section_accelerate>` of the manual for
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more instructions on how to use the accelerated styles effectively.
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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 :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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This fix requires that atoms store torque and angular velocity (omega)
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and a radius as defined by the :doc:`atom_style sphere <atom_style>`
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command. If the *dipole* keyword is used, then they must also store a
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dipole moment as defined by the :doc:`atom_style dipole <atom_style>`
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command.
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All particles in the group must be finite-size spheres. They cannot
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be point particles.
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Related commands
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""""""""""""""""
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:doc:`fix nve <fix_nve>`, :doc:`fix nve/asphere <fix_nve_asphere>`
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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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