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lammps/doc/src/angle_fourier_simple.rst
2020-03-13 16:34:57 -04:00

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.. index:: angle_style fourier/simple
angle_style fourier/simple command
==================================
angle_style fourier/simple/omp command
======================================
Syntax
""""""
.. code-block:: LAMMPS
angle_style fourier/simple
Examples
""""""""
.. code-block:: LAMMPS
angle_style fourier/simple
angle_coeff 100.0 -1.0 1.0
Description
"""""""""""
The *fourier/simple* angle style uses the potential
.. math::
E = K [ 1.0 + c \cos ( n \theta) ]
The following coefficients must be defined for each angle type via the
:doc:`angle_coeff <angle_coeff>` command as in the example above, or in
the data file or restart files read by the :doc:`read_data <read_data>`
or :doc:`read_restart <read_restart>` commands:
* :math:`K` (energy)
* :math:`c` (real)
* :math:`n` (real)
----------
Styles with a *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 on the :doc:`Speed packages <Speed_packages>` doc
page. 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 GPU, USER-INTEL, KOKKOS,
USER-OMP and OPT packages, respectively. They are only enabled if
LAMMPS was built with those packages. See the :doc:`Build package <Build_package>` doc page for more info.
You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the :doc:`-suffix command-line switch <Run_options>` when you invoke LAMMPS, or you can use the
:doc:`suffix <suffix>` command in your input script.
See the :doc:`Speed packages <Speed_packages>` doc page for more
instructions on how to use the accelerated styles effectively.
----------
Restrictions
""""""""""""
This angle style can only be used if LAMMPS was built with the
USER_MISC package. See the :doc:`Build package <Build_package>` doc
page for more info.
Related commands
""""""""""""""""
:doc:`angle_coeff <angle_coeff>`
**Default:** none