99 lines
2.5 KiB
ReStructuredText
99 lines
2.5 KiB
ReStructuredText
.. index:: improper\_style fourier
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improper\_style fourier command
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===============================
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improper\_style fourier/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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improper_style fourier
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Examples
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""""""""
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.. parsed-literal::
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improper_style fourier
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improper_coeff 1 100.0 0.0 1.0 0.5 1
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Description
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"""""""""""
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The *fourier* improper style uses the following potential:
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.. image:: Eqs/improper_fourier.jpg
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:align: center
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where K is the force constant, C0, C1, C2 are dimensionless coefficients,
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and omega is the angle between the IL axis and the IJK plane:
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.. image:: JPG/umbrella.jpg
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:align: center
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If all parameter (see below) is not zero, the all the three possible angles will taken in account.
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The following coefficients must be defined for each improper type via
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the :doc:`improper\_coeff <improper_coeff>` command as in the example
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above, or in the data file or restart files read by the
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:doc:`read\_data <read_data>` or :doc:`read\_restart <read_restart>`
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commands:
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* K (energy)
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* C0 (unitless)
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* C1 (unitless)
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* C2 (unitless)
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* all (0 or 1, optional)
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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 on the :doc:`Speed packages <Speed_packages>` doc
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page. The accelerated styles take the same arguments and should
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produce the same results, except for round-off and precision 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 :doc:`Build package <Build_package>` doc page 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 :doc:`-suffix command-line switch <Run_options>` when you invoke LAMMPS, or you can use the
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:doc:`suffix <suffix>` command in your input script.
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See the :doc:`Speed packages <Speed_packages>` doc page for more
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instructions on how to use the accelerated styles effectively.
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----------
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Restrictions
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""""""""""""
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This angle style can only be used if LAMMPS was built with the
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USER\_MISC package. See the :doc:`Build package <Build_package>` doc
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page for more info.
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Related commands
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""""""""""""""""
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:doc:`improper\_coeff <improper_coeff>`
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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: Commands_all.html
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