64 lines
1.9 KiB
ReStructuredText
64 lines
1.9 KiB
ReStructuredText
.. index:: pair_style none
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pair_style none command
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=======================
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Syntax
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""""""
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.. code-block:: LAMMPS
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pair_style none
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Examples
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""""""""
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.. code-block:: LAMMPS
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pair_style none
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Description
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"""""""""""
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Using a pair style of *none* means that any previous pair style setting
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will be deleted and pairwise forces and energies are not computed.
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As a consequence there will be a pairwise force cutoff of 0.0, which has
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implications for the default setting of the neighbor list and the
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communication cutoff. Those are the sum of the largest pairwise cutoff
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and the neighbor skin distance (see the documentation of the
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:doc:`neighbor <neighbor>` command and the :doc:`comm_modify
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<comm_modify>` command). When you have bonds, angles, dihedrals, or
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impropers defined at the same time, you must set the communication
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cutoff so that communication cutoff distance is large enough to acquire
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and communicate sufficient ghost atoms from neighboring subdomains as
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needed for computing bonds, angles, etc.
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A pair style of *none* will also not request a pairwise neighbor list.
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However if the :doc:`neighbor <neighbor>` style is *bin*, data
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structures for binning are still allocated. If the neighbor list cutoff
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is small, then these data structures can consume a large amount of
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memory. So you should either set the neighbor style to *nsq* or set the
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skin distance to a larger value.
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See the :doc:`pair_style zero <pair_zero>` for a way to set a pairwise
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cutoff and thus trigger the building of a neighbor lists and setting
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a corresponding communication cutoff, but compute no pairwise interactions.
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Restrictions
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""""""""""""
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You must not use a :doc:`pair_coeff <pair_coeff>` command with this pair
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style. Since there is no interaction computed, you cannot set any
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coefficients for it.
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Related commands
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""""""""""""""""
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:doc:`pair_style zero <pair_zero>`
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Default
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"""""""
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none
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