lammps/doc/partition.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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<H3>partition command
</H3>
<P><B>Syntax:</B>
</P>
<PRE>partition style N command ...
</PRE>
<UL><LI>style = <I>yes</I> or <I>no</I>
<LI>N = partition number (see asterisk form below)
<LI>command = any LAMMPS command
</UL>
<P><B>Examples:</B>
</P>
<PRE>partition yes 1 processors 4 10 6
partition no 5 print "Active partition"
partition yes *5 fix all nve
partition yes 6* fix all nvt temp 1.0 1.0 0.1
</PRE>
<P><B>Description:</B>
</P>
<P>This command invokes the specified command on a subset of the
partitions of processors you have defined via the -partition
command-line switch. See <A HREF = "Section_start.html#start_7">Section_start 6</A>
for an explanation of the switch.
</P>
<P>Normally, every input script command in your script is invoked by
every partition. This behavior can be modified by defining world- or
universe-style <A HREF = "variable.html">variables</A> that have different values
for each partition. This mechanism can be used to cause your script
to jump to different input script files on different partitions, if
such a variable is used in a <A HREF = "jump.html">jump</A> command.
</P>
<P>The "partition" command is another mechanism for having as input
script operate differently on different partitions. It is basically a
prefix on any LAMMPS command. The commmand will only be invoked on
the partition(s) specified by the <I>style</I> and <I>N</I> arguments.
</P>
<P>If the <I>style</I> is <I>yes</I>, the command will be invoked on any partition
which matches the <I>N</I> argument. If the <I>style</I> is <I>no</I> the command
will be invoked on all the partitions which do not match the Np
argument.
</P>
<P>Partitions are numbered from 1 to Np, where Np is the number of
partitions specified by the <A HREF = "Section_start.html#start_7">-partition command-line
switch</A>.
</P>
<P><I>N</I> can be specified in one of two ways. An explicit numeric value
can be used, as in the 1st example above. Or a wild-card asterisk can
be used to span a range of partition numbers. This takes the form "*"
or "*n" or "n*" or "m*n". An asterisk with no numeric values means
all partitions from 1 to Np. A leading asterisk means all partitions
from 1 to n (inclusive). A trailing asterisk means all partitions
from n to Np (inclusive). A middle asterisk means all partitions from
m to n (inclusive).
</P>
<P>This command can be useful for the "run_style verlet/split" command
which imposed requirements on how the <A HREF = "processors.html">processors</A>
command lays out a 3d grid of processors in each of 2 partitions.
</P>
<P><B>Restrictions:</B> none
</P>
<P><B>Related commands:</B>
</P>
<P><A HREF = "run_style.html">run_style verlet/split</A>
</P>
<P><B>Default:</B> none
</P>
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