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>bond_style hybrid command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>bond_style hybrid style1 style2 ...
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</PRE>
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<UL><LI>style1,style2 = list of one or more bond styles
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>bond_style hybrid harmonic fene
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bond_coeff 1 harmonic 80.0 1.2
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bond_coeff 2* fene 30.0 1.5 1.0 1.0
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>The <I>hybrid</I> style enables the use of multiple bond styles in one
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simulation. A bond style is assigned to each bond type. For example,
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bonds in a polymer flow (of bond type 1) could be computed with a
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<I>fene</I> potential and bonds in the wall boundary (of bond type 2) could
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be computed with a <I>harmonic</I> potential. The assignment of bond type
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to style is made via the <A HREF = "bond_coeff.html">bond_coeff</A> command or in
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the data file.
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</P>
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<P>In the bond_coeff command, the first coefficient sets the bond style
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and the remaining coefficients are those appropriate to that style.
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In the example above, the 2 bond_coeff commands would set bonds of
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bond type 1 to be computed with a <I>harmonic</I> potential with
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coefficients 80.0, 1.2 for K, r0. All other bond types (2-N) would be
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computed with a <I>fene</I> potential with coefficients 30.0, 1.5, 1.0, 1.0
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for K, R0, epsilon, sigma.
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</P>
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2011-06-01 23:21:07 +08:00
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<P>If bond coefficients are specified in the data file read via
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the <A HREF = "read_data.html">read_data</A> command, then the same string,
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e.g. "harmonic" or "fene", must be listed as the 1st argument
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of each line in the "Bond Coeffs" section, e.g.
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</P>
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<PRE>1 harmonic 80.0 1.2
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</PRE>
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2009-01-06 06:26:31 +08:00
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<P>A bond style of <I>none</I> can be specified as the 2nd argument to the
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2011-06-01 23:21:07 +08:00
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bond_coeff command or the 1st argument in the data file, if you desire
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to turn off certain bond types.
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2006-09-22 00:22:34 +08:00
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</P>
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2007-06-25 22:36:36 +08:00
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<P><B>Restrictions:</B>
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</P>
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<P>This bond style can only be used if LAMMPS was built with the
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"molecular" package (which it is by default). See the <A HREF = "Section_start.html#2_3">Making
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LAMMPS</A> section for more info on packages.
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2006-09-22 00:22:34 +08:00
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</P>
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2008-10-09 22:47:45 +08:00
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<P>Unlike other bond styles, the hybrid bond style does not store bond
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coefficient info for individual sub-styles in a <A HREF = "restart.html">binary restart
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files</A>. Thus when retarting a simulation from a restart
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file, you need to re-specify bond_coeff commands.
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</P>
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2006-09-22 00:22:34 +08:00
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "bond_coeff.html">bond_coeff</A>, <A HREF = "delete_bonds.html">delete_bonds</A>
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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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