2006-09-22 00:22:34 +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 wall/reflect command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>fix ID group-ID wall/reflect keyword ...
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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>wall/reflect = style name of this fix command
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<LI>one or more keyword/value pairs may be appended to the args
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<LI>keyword = <I>xlo</I> or <I>xhi</I> or <I>ylo</I> or <I>yhi</I> or <I>zlo</I> or <I>zhi</I>
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>fix xwalls all wall/reflect xlo xhi
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fix walls all wall/reflect xlo ylo zlo xhi yhi zhi
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Bound the simulation with one or more walls which reflect particles
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when they attempt to move thru them. Normally, the simulation domain
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should be set non-periodic via the <A HREF = "boundary.html">boundary</A> command in
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any dimension that has such a wall, but LAMMPS does not check for this
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condition.
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</P>
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<P>Reflection means that if an atom moves outside the box on a timestep
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by a distance delta (e.g. due to <A HREF = "fix_nve.html">fix nve</A>), then it is
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put back inside the box by the same delta and the sign of the
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corresponding component of its velocity is flipped.
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</P>
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2007-02-17 05:06:13 +08:00
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<P>This fix performs its operations at the same point in the timestep as
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other time integration fixes, such as <A HREF = "fix_nve.html">fix nve</A>, <A HREF = "fix_nvt.html">fix
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nvt</A>, or <A HREF = "fix_npt.html">fix npt</A>. It is important that it
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be the last such fix specified in the input script, since it changes
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the atom positions set by those fixes to insure atoms stay within the
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simulation box.
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</P>
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2006-09-22 00:22:34 +08:00
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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_lj93.html">fix wall/lj93</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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</HTML>
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