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>angle_style command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>angle_style style
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</PRE>
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<UL><LI>style = <I>none</I> or <I>hybrid</I> or <I>charmm</I> or <I>class2</I> or <I>cosine</I> or <I>cosine/squared</I> or <I>harmonic</I>
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>angle_style harmonic
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angle_style charmm
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angle_style hybrid harmonic cosine
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Set the formula(s) LAMMPS uses to compute angle interactions between
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triplets of atoms, which remain in force for the duration of the
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simulation. The list of angle triplets is read in by a
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<A HREF = "read_data.html">read_data</A> or <A HREF = "read_restart.html">read_restart</A> command
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from a data or restart file.
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</P>
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<P>Hybrid models where angles are computed using different angle
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potentials can be setup using the <I>hybrid</I> angle style.
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</P>
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<P>The coefficients associated with a angle style can be specified in a
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data or restart file or via the <A HREF = "angle_coeff.html">angle_coeff</A> command.
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</P>
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2007-06-25 22:36:36 +08:00
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<P>All angle potentials store their coefficient data in binary restart
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files which means angle_style and <A HREF = "angle_coeff.html">angle_coeff</A>
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commands do not need to be re-specified in an input script that
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restarts a simulation. See the <A HREF = "read_restart.html">read_restart</A>
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command for details on how to do this. The one exception is that
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angle_style <I>hybrid</I> only stores the list of sub-styles in the restart
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file; angle coefficients need to be re-specified.
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</P>
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<P>IMPORTANT NOTE: When both an angle and pair style is defined, the
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<A HREF = "special_bonds.html">special_bonds</A> command often needs to be used to
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turn off (or weight) the pairwise interaction that would otherwise
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exist between 3 bonded atoms.
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</P>
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2006-09-22 00:22:34 +08:00
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<P>In the formulas listed for each angle style, <I>theta</I> is the angle
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between the 3 atoms in the angle.
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</P>
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<HR>
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<P>Here is an alphabetic list of angle styles defined in LAMMPS. Click on
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the style to display the formula it computes and coefficients
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specified by the associated <A HREF = "angle_coeff.html">angle_coeff</A> command:
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</P>
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2007-02-10 05:37:30 +08:00
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<UL><LI><A HREF = "angle_none.html">angle_style none</A> - turn off angle interactions
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<LI><A HREF = "angle_hybrid.html">angle_style hybrid</A> - define multiple styles of angle interactions
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2006-09-22 00:22:34 +08:00
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</UL>
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2007-02-10 05:37:30 +08:00
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<UL><LI><A HREF = "angle_charmm.html">angle_style charmm</A> - CHARMM angle
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<LI><A HREF = "angle_class2.html">angle_style class2</A> - COMPASS (class 2) angle
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<LI><A HREF = "angle_cosine.html">angle_style cosine</A> - cosine angle potential
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2008-01-22 07:52:32 +08:00
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<LI><A HREF = "angle_cosine_delta.html">angle_style cosine/delta</A> - difference of cosines angle potential
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2007-02-10 05:37:30 +08:00
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<LI><A HREF = "angle_cosine_squared.html">angle_style cosine/squared</A> - cosine squared angle potential
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2009-08-11 04:13:44 +08:00
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<LI><A HREF = "angle_harmonic.html">angle_style harmonic</A> - harmonic angle
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<LI><A HREF = "angle_table.html">angle_style table</A> - tabulated by angle
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2006-09-22 00:22:34 +08:00
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</UL>
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2009-11-05 06:12:52 +08:00
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<P>There are also additional angle styles submitted by users which are
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included in the LAMMPS distribution. The list of these with links to
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the individual styles are given in the angle section of <A HREF = "Section_commands.html#3_5">this
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page</A>.
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</P>
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2006-09-22 00:22:34 +08:00
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<HR>
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<P><B>Restrictions:</B>
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</P>
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<P>Angle styles can only be set for atom_styles that allow angles to be
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defined.
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</P>
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2007-06-25 22:36:36 +08:00
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<P>Most angle styles are part of the "molecular" package. They are only
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enabled if LAMMPS was built with that package. See the <A HREF = "Section_start.html#2_3">Making
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LAMMPS</A> section for more info on packages. The
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doc pages for individual bond potentials tell if it is part of a
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package.
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2006-09-22 00:22:34 +08:00
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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 = "angle_coeff.html">angle_coeff</A>
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</P>
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<P><B>Default:</B>
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</P>
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<PRE>angle_style none
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</PRE>
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</HTML>
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