2014-03-10 23:21:49 +08:00
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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>fix oneway command
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</H3>
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<P><B>Syntax:</B>
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</P>
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2014-08-27 00:44:13 +08:00
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<PRE>fix ID group-ID oneway N region-ID direction
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2014-03-10 23:21:49 +08:00
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</PRE>
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<UL><LI>ID, group-ID are documented in <A HREF = "fix.html">fix</A> command
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<LI>oneway = style name of this fix command
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<LI>N = apply this fix every this many timesteps
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<LI>region-ID = ID of region where fix is active
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<LI>direction = <I>x</I> or <I>-x</I> or <I>y</I> or <I>-y</I> or <I>z</I> or <I>-z</I> = coordinate and direction of the oneway constraint
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</UL>
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<P><B>Examples:</B>
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</P>
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2014-08-27 00:44:13 +08:00
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<PRE>fix ions oneway 10 semi -x
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fix all oneway 1 left -z
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fix all oneway 1 right z
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2014-03-10 23:21:49 +08:00
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Enforce that particles in the group and in a given region can only
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move in one direction. This is done by reversing a particle's
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velocity component, if it has the wrong sign in the specified
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dimension. The effect is that the particle moves in one direction
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only.
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</P>
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<P>This can be used, for example, as a simple model of a semi-permeable
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membrane, or as an implementation of Maxwell's demon.
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</P>
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<HR>
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<P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>
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</P>
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<P>No information about this fix is written to <A HREF = "restart.html">binary restart
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files</A>. None of the <A HREF = "fix_modify.html">fix_modify</A> options
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are relevant to this fix. No global or per-atom quantities are stored
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by this fix for access by various <A HREF = "Section_howto.html#howto_15">output
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commands</A>. No parameter of this fix can
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be used with the <I>start/stop</I> keywords of the <A HREF = "run.html">run</A> command.
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This fix is not invoked during <A HREF = "minimize.html">energy minimization</A>.
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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 = "fix_wall_reflect.html">fix wall/reflect</A> command
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</P>
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<P><B>Default:</B> none
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</P>
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<HR>
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</HTML>
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