2007-03-23 01:05:12 +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 nve/noforce 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 nve
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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>nve/noforce = style name of this fix command
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>fix 3 wall nve/noforce
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Perform updates of position, but not velocity for atoms in the group
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each timestep. In other words, the force on the atoms is ignored and
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2007-03-23 01:14:05 +08:00
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their velocity is not updated. The atom velocities are used to update
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their positions.
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2007-03-23 01:05:12 +08:00
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</P>
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2007-03-23 01:14:05 +08:00
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<P>This can be useful for wall atoms, when you set their velocities, and
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2007-03-23 01:05:12 +08:00
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want the wall to move (or stay stationary) in a prescribed fashion.
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</P>
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<P>This can also be accomplished via the <A HREF = "fix_setforce.html">fix setforce</A>
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command, but with fix nve/noforce, the forces on the wall atoms are
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2007-03-23 01:14:05 +08:00
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unchanged, and can thus be printed by the <A HREF = "dump.html">dump</A> command or
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queried with an equal-style <A HREF = "variable.html">variable</A> that uses the
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fcm() group function to compute the total force on the group of atoms.
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2007-03-23 01:05:12 +08:00
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</P>
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2007-10-11 06:28:11 +08:00
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<P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>
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2007-06-26 08:03:39 +08:00
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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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2010-04-03 00:51:06 +08:00
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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#4_15">output
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2007-10-11 06:28:11 +08:00
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commands</A>. No parameter of this fix can be
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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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2007-06-26 08:03:39 +08:00
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</P>
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2007-03-23 01:05:12 +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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2007-03-23 01:14:05 +08:00
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<P><A HREF = "fix_nve.html">fix nve</A>
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2007-03-23 01:05:12 +08:00
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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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