lammps/doc/compute_event_displace.html

62 lines
1.9 KiB
HTML

<HTML>
<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>
</CENTER>
<HR>
<H3>compute event/displace command
</H3>
<P><B>Syntax:</B>
</P>
<PRE>compute ID group-ID event/displace threshold
</PRE>
<UL><LI>ID, group-ID are documented in <A HREF = "compute.html">compute</A> command
<LI>event/displace = style name of this compute command
<LI>threshold = minimum distance anyparticle must move to trigger an event (distance units)
</UL>
<P><B>Examples:</B>
</P>
<PRE>compute 1 all event/displace 0.5
</PRE>
<P><B>Description:</B>
</P>
<P>Define a computation that flags an "event" if any particle in the
group has moved a distance greater than the specified threshold
distance when compared to a previously stored reference state
(i.e. the previous event). This compute is typically used in
conjunction with the <A HREF = "prd.html">prd</A> command, to detect if a transition
to a new minimum energy basin has occurred.
</P>
<P>This value calculated by the compute is equal to 0 if no particle has
moved far enough, and equal to 1 if one or more particles have moved
further than the threshold distance.
</P>
<P><B>Output info:</B>
</P>
<P>This compute calculates a global scalar (the flag). This value can be
used by any command that uses a global scalar value from a compute as
input. See <A HREF = "Section_howto.html#4_15">this section</A> for an overview of
LAMMPS output options.
</P>
<P>The scalar value calculated by this compute is "intensive". The
scalar value will be a 0 or 1 as explained above.
</P>
<P><B>Restrictions:</B>
</P>
<P>This command can only be used if LAMMPS was built with the "replica"
package. See the <A HREF = "Section_start.html#2_3">Making LAMMPS</A> section for
more info on packages.
</P>
<P><B>Related commands:</B>
</P>
<P><A HREF = "prd.html">prd</A>
</P>
<P><B>Default:</B> none
</P>
</HTML>