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_coeff 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_coeff N args
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</PRE>
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2008-03-01 09:13:20 +08:00
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<UL><LI>N = angle type (see asterisk form below)
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2006-09-22 00:22:34 +08:00
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<LI>args = coefficients for one or more angle types
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>angle_coeff 1 300.0 107.0
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angle_coeff * 5.0
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angle_coeff 2*10 5.0
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Specify the angle force field coefficients for one or more angle types.
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The number and meaning of the coefficients depends on the angle style.
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Angle coefficients can also be set in the data file read by the
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<A HREF = "read_data.html">read_data</A> command or in a restart file.
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</P>
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<P>N can be specified in one of two ways. An explicit numeric value can
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2008-03-19 04:18:54 +08:00
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be used, as in the 1st example above. Or a wild-card asterisk can be
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2006-09-22 00:22:34 +08:00
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used to set the coefficients for multiple angle types. This takes the
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form "*" or "*n" or "n*" or "m*n". If N = the number of angle types,
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2008-03-01 09:13:20 +08:00
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then an asterisk with no numeric values means all types from 1 to N. A
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leading asterisk means all types from 1 to n (inclusive). A trailing
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asterisk means all types from n to N (inclusive). A middle asterisk
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2006-09-22 00:22:34 +08:00
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means all types from m to n (inclusive).
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</P>
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2006-09-29 03:22:09 +08:00
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<P>Note that using an angle_coeff command can override a previous setting
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2006-09-22 00:22:34 +08:00
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for the same angle type. For example, these commands set the coeffs
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for all angle types, then overwrite the coeffs for just angle type 2:
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</P>
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<PRE>angle_coeff * 200.0 107.0 1.2
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angle_coeff 2 50.0 107.0
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</PRE>
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<P>A line in a data file that specifies angle coefficients uses the exact
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same format as the arguments of the angle_coeff command in an input
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2006-09-29 03:22:09 +08:00
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script, except that wild-card asterisks should not be used since
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2006-09-22 00:22:34 +08:00
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coefficients for all N types must be listed in the file. For example,
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under the "Angle Coeffs" section of a data file, the line that
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corresponds to the 1st example above would be listed as
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</P>
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<PRE>1 300.0 107.0
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</PRE>
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2010-11-18 02:25:09 +08:00
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<P>The <A HREF = "angle_class2.html">angle_style class2</A> is an exception to this
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rule, in that an additional argument is used in the input script to
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allow specification of the cross-term coefficients. See its
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doc page for details.
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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>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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2010-10-26 04:29:36 +08:00
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<LI><A HREF = "angle_cosine_periodic.html">angle_style cosine/periodic</A> - DREIDING angle
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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>This command must come after the simulation box is defined by a
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<A HREF = "read_data.html">read_data</A>, <A HREF = "read_restart.html">read_restart</A>, or
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<A HREF = "create_box.html">create_box</A> command.
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</P>
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<P>An angle style must be defined before any angle coefficients are
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set, either in the input script or in a data file.
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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_style.html">angle_style</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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