Update docs: angle_hybrid

.. index:: angle\_style hybrid

.. index:: angle_style hybrid

angle\_style hybrid command

===========================

angle_style hybrid command

==========================

Syntax

""""""

.. parsed-literal::

.. code-block:: LAMMPS

   angle_style hybrid style1 style2 ...

""""""""

.. parsed-literal::

.. code-block:: LAMMPS

   angle_style hybrid harmonic cosine

   angle_coeff 1 harmonic 80.0 30.0

   angle_coeff 2\* cosine 50.0

   angle_coeff 2* cosine 50.0

Description

"""""""""""

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 :doc:`angle\_coeff <angle_coeff>`

of angle type to style is made via the :doc:`angle_coeff <angle_coeff>`

command or in the data file.

In the angle\_coeff commands, the name of an angle style must be added

In the :doc:`angle_coeff <angle_coeff>` commands, the name of an angle style must be added

after the angle type, with the remaining coefficients being those

appropriate to that style.  In the example above, the 2 angle\_coeff

commands set angles of angle type 1 to be computed with a *harmonic*

potential with coefficients 80.0, 30.0 for K, theta0.  All other angle

types (2-N) are computed with a *cosine* potential with coefficient

50.0 for K.

potential with coefficients 80.0, 30.0 for :math:`K`, :math:`\theta_0`.  All other angle

types :math:`(2 - N)` are computed with a *cosine* potential with coefficient

50.0 for :math:`K`.

If angle coefficients are specified in the data file read via the

:doc:`read\_data <read_data>` command, then the same rule applies.

:doc:`read_data <read_data>` command, then the same rule applies.

E.g. "harmonic" or "cosine", must be added after the angle type, for each

line in the "Angle Coeffs" section, e.g.

specified at all for angle types that are not *class2*\ .

An angle style of *none* with no additional coefficients can be used

in place of an angle style, either in a input script angle\_coeff

in place of an angle style, either in a input script :doc:`angle_coeff <angle_coeff>`

command or in the data file, if you desire to turn off interactions

for specific angle types.

Unlike other angle styles, the hybrid angle style does not store angle

coefficient info for individual sub-styles in a :doc:`binary restart files <restart>`.  Thus when restarting a simulation from a restart

file, you need to re-specify angle\_coeff commands.

file, you need to re-specify :doc:`angle_coeff <angle_coeff>` commands.

Related commands

""""""""""""""""

:doc:`angle\_coeff <angle_coeff>`

:doc:`angle_coeff <angle_coeff>`

**Default:** none

.. _lws: http://lammps.sandia.gov

.. _ld: Manual.html

.. _lc: Commands_all.html

"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)

:link(ld,Manual.html)

:link(lc,Commands_all.html)

:line

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 30.0

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 commands, the name of an angle style must be added

after the angle type, with the remaining coefficients being those

appropriate to that style.  In the example above, the 2 angle_coeff

commands set angles of angle type 1 to be computed with a {harmonic}

potential with coefficients 80.0, 30.0 for K, theta0.  All other angle

types (2-N) are computed with a {cosine} potential with coefficient

50.0 for K.

If angle coefficients are specified in the data file read via the

"read_data"_read_data.html command, then the same rule applies.

E.g. "harmonic" or "cosine", must be added after the angle type, for each

line in the "Angle Coeffs" section, e.g.

Angle Coeffs :pre

1 harmonic 80.0 30.0

2 cosine 50.0

... :pre

If {class2} is one of the angle hybrid styles, the same rule holds for

specifying additional BondBond (and BondAngle) coefficients either via

the input script or in the data file.  I.e. {class2} must be added to

each line after the angle type.  For lines in the BondBond (or

BondAngle) section of the data file for angle types that are not

{class2}, you must use an angle style of {skip} as a placeholder, e.g.

BondBond Coeffs :pre

1 skip

2 class2 3.6512 1.0119 1.0119

... :pre

Note that it is not necessary to use the angle style {skip} in the

input script, since BondBond (or BondAngle) coefficients need not be

specified at all for angle types that are not {class2}.

An angle style of {none} with no additional coefficients can be used

in place of an angle style, either in a input script angle_coeff

command or in the data file, if you desire to turn off interactions

for specific angle types.

:line

[Restrictions:]

This angle style can only be used if LAMMPS was built with the

MOLECULE package.  See the "Build package"_Build_package.html doc page

for more info.

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 restarting a simulation from a restart

file, you need to re-specify angle_coeff commands.

[Related commands:]

"angle_coeff"_angle_coeff.html

[Default:] none