forked from lijiext/lammps
98 lines
2.8 KiB
Plaintext
98 lines
2.8 KiB
Plaintext
.. index:: pair_style zero
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pair_style zero command
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=======================
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Syntax
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""""""
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.. parsed-literal::
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pair_style zero cutoff *nocoeff*
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* zero = style name of this pair style
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cutoff = global cutoff (distance units)
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nocoeff = ignore all pair_coeff parameters (optional)
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Examples
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""""""""
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.. parsed-literal::
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pair_style zero 10.0
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pair_style zero 5.0 nocoeff
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pair_coeff * *
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pair_coeff 1 2*4 3.0
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Description
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"""""""""""
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Define a global or per-type cutoff length for the purpose of
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building a neighbor list and acquiring ghost atoms, but do
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not compute any pairwise forces or energies.
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This can be useful for fixes or computes which require a neighbor list
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to enumerate pairs of atoms within some cutoff distance, but when
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pairwise forces are not otherwise needed. Examples are the :doc:`fix bond/create <fix_bond_create>`, :doc:`compute rdf <compute_rdf>`,
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:doc:`compute voronoi/atom <compute_voronoi_atom>` commands.
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Note that the :doc:`comm_modify cutoff <comm_modify>` command can be
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used to insure communication of ghost atoms even when a pair style is
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not defined, but it will not trigger neighbor list generation.
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The optional *nocoeff* flag allows to read data files with a PairCoeff
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section for any pair style. Similarly, any pair_coeff commands
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will only be checked for the atom type numbers and the rest ignored.
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In this case, only the global cutoff will be used.
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The following coefficients must be defined for each pair of atoms
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types via the :doc:`pair_coeff <pair_coeff>` command as in the examples
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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, or by mixing as described below:
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* cutoff (distance units)
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This coefficient is optional. If not specified, the global cutoff
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specified in the pair_style command is used. If the pair_style has
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been specified with the optional *nocoeff* flag, then a cutoff
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pair coefficient is ignored.
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----------
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**Mixing, shift, table, tail correction, restart, rRESPA info**\ :
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The cutoff distance for this pair style can be mixed. The default mix
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value is *geometric*\ . See the "pair_modify" command for details.
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This pair style does not support the :doc:`pair_modify <pair_modify>`
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shift, table, and tail options.
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This pair style writes its information to :doc:`binary restart files <restart>`, so pair_style and pair_coeff commands do not need
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to be specified in an input script that reads a restart file.
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This pair style can only be used via the *pair* keyword of the
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:doc:`run_style respa <run_style>` command. It does not support the
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*inner*\ , *middle*\ , *outer* keywords.
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----------
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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:`pair_style none <pair_none>`
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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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