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fix_nve_sphere.txt
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.. index:: fix nve/sphere
fix nve/sphere command
======================
fix nve/sphere/omp command
==========================
Syntax
""""""
.. parsed-literal::
fix ID group-ID nve/sphere
* ID, group-ID are documented in :doc:`fix <fix>` command
* nve/sphere = style name of this fix command
* zero or more keyword/value pairs may be appended
* keyword = *update*
.. parsed-literal::
*update* value = *dipole*
dipole = update orientation of dipole moment during integration
Examples
""""""""
.. parsed-literal::
fix 1 all nve/sphere
fix 1 all nve/sphere update dipole
Description
"""""""""""
Perform constant NVE integration to update position, velocity, and
angular velocity for finite-size spherical particles in the group each
timestep. V is volume; E is energy. This creates a system trajectory
consistent with the microcanonical ensemble.
This fix differs from the :doc:`fix nve <fix_nve>` command, which
assumes point particles and only updates their position and velocity.
If the *update* keyword is used with the *dipole* value, then the
orientation of the dipole moment of each particle is also updated
during the time integration. This option should be used for models
where a dipole moment is assigned to finite-size particles,
e.g. spheroids via use of the :doc:`atom_style hybrid sphere dipole <atom_style>` command.
----------
Styles with a *cuda*, *gpu*, *intel*, *kk*, *omp*, or *opt* suffix are
functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
hardware, as discussed in :doc:`Section_accelerate <Section_accelerate>`
of the manual. The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.
These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
KOKKOS, USER-OMP and OPT packages, respectively. They are only
enabled if LAMMPS was built with those packages. See the :ref:`Making LAMMPS <start_3>` section for more info.
You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the :ref:`-suffix command-line switch <start_7>` when you invoke LAMMPS, or you can
use the :doc:`suffix <suffix>` command in your input script.
See :doc:`Section_accelerate <Section_accelerate>` of the manual for
more instructions on how to use the accelerated styles effectively.
----------
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 not invoked during :doc:`energy minimization <minimize>`.
Restrictions
""""""""""""
This fix requires that atoms store torque and angular velocity (omega)
and a radius as defined by the :doc:`atom_style sphere <atom_style>`
command. If the *dipole* keyword is used, then they must also store a
dipole moment as defined by the :doc:`atom_style dipole <atom_style>`
command.
All particles in the group must be finite-size spheres. They cannot
be point particles.
Related commands
""""""""""""""""
:doc:`fix nve <fix_nve>`, :doc:`fix nve/asphere <fix_nve_asphere>`
**Default:** none
.. _lws: http://lammps.sandia.gov
.. _ld: Manual.html
.. _lc: Section_commands.html#comm
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