lammps/doc/angle_hybrid.txt

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angle_style hybrid command :h3

[Syntax:]

angle_style hybrid style1 style2 ... :pre

style1,style2 = list of one or more angle styles :ul

[Examples:]

angle_style hybrid harmonic cosine
angle_coeff 1 harmonic 80.0 1.2
angle_coeff 2* cosine 50.0  :pre

[Description:]

The {hybrid} style enables the use of multiple angle styles in one
simulation.  An angle style is assigned to each angle type.  For
example, angles in a polymer flow (of angle type 1) could be computed
with a {harmonic} potential and angles in the wall boundary (of angle
type 2) could be computed with a {cosine} potential.  The assignment
of angle type to style is made via the "angle_coeff"_angle_coeff.html
command or in the data file.

In the angle_coeff command, the first coefficient sets the angle style
and the remaining coefficients are those appropriate to that style.
In the example above, the 2 angle_coeff commands would set angles of
angle type 1 to be computed with a {harmonic} potential with
coefficients 80.0, 1.2 for K, r0.  All other angle types (2-N) would
be computed with a {cosine} potential with coefficient 50.0 for K.

If the angle {class2} potential is one of the hybrid styles, it
requires additional BondBond and BondAngle coefficients be specified
in the data file.  These lines must also have an additional "class2"
argument added after the angle type.  For angle types which are
assigned to other hybrid styles, use the style name (e.g. "harmonic")
appropriate to that style.  The BondBond and BondAngle coeffs for that
angle type will then be ignored.

An angle style of {none} can be specified as the 2nd argument to the
angle_coeff command, if you desire to turn off certain angle types.

[Restrictions:]

This angle style can only be used if LAMMPS was built with the
"molecular" package (which it is by default).  See the "Making
LAMMPS"_Section_start.html#2_3 section for more info on packages.

Unlike other angle styles, the hybrid angle style does not store angle
coefficient info for individual sub-styles in a "binary restart
files"_restart.html.  Thus when retarting a simulation from a restart
file, you need to re-specify angle_coeff commands.

[Related commands:]

"angle_coeff"_angle_coeff.html

[Default:] none