7eb926c853
explain that pair style none is effectively deleting any existing pair style and that communication and neighbor list cutoff are affected. update those explanations for changes to LAMMPS that allow adjusting those not just with the neighbor list skin. Also add that pair_coeff must not be used.
64 lines
1.9 KiB
ReStructuredText
64 lines
1.9 KiB
ReStructuredText
.. index:: pair_style none
|
|
|
|
pair_style none command
|
|
=======================
|
|
|
|
Syntax
|
|
""""""
|
|
|
|
.. code-block:: LAMMPS
|
|
|
|
pair_style none
|
|
|
|
Examples
|
|
""""""""
|
|
|
|
.. code-block:: LAMMPS
|
|
|
|
pair_style none
|
|
|
|
Description
|
|
"""""""""""
|
|
|
|
Using a pair style of *none* means that any previous pair style setting
|
|
will be deleted and pairwise forces and energies are not computed.
|
|
|
|
As a consequence there will be a pairwise force cutoff of 0.0, which has
|
|
implications for the default setting of the neighbor list and the
|
|
communication cutoff. Those are the sum of the largest pairwise cutoff
|
|
and the neighbor skin distance (see the documentation of the
|
|
:doc:`neighbor <neighbor>` command and the :doc:`comm_modify
|
|
<comm_modify>` command). When you have bonds, angles, dihedrals, or
|
|
impropers defined at the same time, you must set the communication
|
|
cutoff so that communication cutoff distance is large enough to acquire
|
|
and communicate sufficient ghost atoms from neighboring sub-domains as
|
|
needed for computing bonds, angles, etc.
|
|
|
|
A pair style of *none* will also not request a pairwise neighbor list.
|
|
However if the :doc:`neighbor <neighbor>` style is *bin*, data
|
|
structures for binning are still allocated. If the neighbor list cutoff
|
|
is small, then these data structures can consume a large amount of
|
|
memory. So you should either set the neighbor style to *nsq* or set the
|
|
skin distance to a larger value.
|
|
|
|
See the :doc:`pair_style zero <pair_zero>` for a way to set a pairwise
|
|
cutoff and thus trigger the building of a neighbor lists and setting
|
|
a corresponding communication cutoff, but compute no pairwise interactions.
|
|
|
|
Restrictions
|
|
""""""""""""
|
|
|
|
You must not use a :doc:`pair_coeff <pair_coeff>` command with this pair
|
|
style. Since there is no interaction computed, you cannot set any
|
|
coefficients for it.
|
|
|
|
Related commands
|
|
""""""""""""""""
|
|
|
|
:doc:`pair_style zero <pair_zero>`
|
|
|
|
Default
|
|
"""""""
|
|
|
|
none
|