forked from lijiext/lammps
66 lines
2.0 KiB
HTML
66 lines
2.0 KiB
HTML
<HTML>
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<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
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<HR>
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<H3>neighbor command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>neighbor skin style
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</PRE>
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<UL><LI>skin = extra distance beyond force cutoff (distance units)
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<LI>style = <I>bin</I> or <I>nsq</I>
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>neighbor 0.3 bin
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neighbor 2.0 nsq
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</PRE>
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<P><B>Description: </B>
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</P>
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<P>This command sets parameters that affect the building of the pairwise
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neighbor list. All atom pairs within a cutoff distance equal to the
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their force cutoff plus the <I>skin</I> distance are stored in the list.
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Typically, the larger the skin distance, the less often neighbor lists
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need to be built, but more pairs must be checked for possible force
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interactions every timestep.
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</P>
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<P>The <I>style</I> value chooses what algorithm is used to build the list.
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<I>Binning</I> is an operation that scales linearly with N, the number of
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atoms on a processor. It is almost always faster than the <I>nsq</I> style
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which scales as N^2. For unsolvated small molecules in a non-periodic
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box, the <I>nsq</I> choice can sometimes be faster. Either style should
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give the same answers.
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</P>
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<P>The default values for <I>skin</I> and <I>style</I> depend on the choice of
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units for the simulation.
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</P>
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<P>The <A HREF = "neigh_modify.html">neigh_modify</A> command has additional options
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that control how often neighbor lists are built and which pairs are
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stored in the list.
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</P>
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<P>When a run is finished, counts of the number of neighbors stored in
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the pairwise list and the number of times neighbor lists were built
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are printed to the screen and log file. See <A HREF = "Section_start.html#2_5">this
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section</A> for details.
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</P>
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<P><B>Restrictions:</B> none
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "neigh_modify.html">neigh_modify</A>, <A HREF = "units.html">units</A>
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</P>
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<P><B>Default:</B>
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</P>
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<PRE>0.3 bin for lj units
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2.0 bin for real or metal units
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</PRE>
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