forked from lijiext/lammps
90 lines
3.0 KiB
Plaintext
90 lines
3.0 KiB
Plaintext
"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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angle_style hybrid command :h3
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[Syntax:]
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angle_style hybrid style1 style2 ... :pre
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style1,style2 = list of one or more angle styles :ul
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[Examples:]
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angle_style hybrid harmonic cosine
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angle_coeff 1 harmonic 80.0 30.0
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angle_coeff 2* cosine 50.0 :pre
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[Description:]
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The {hybrid} style enables the use of multiple angle styles in one
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simulation. An angle style is assigned to each angle type. For
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example, angles in a polymer flow (of angle type 1) could be computed
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with a {harmonic} potential and angles in the wall boundary (of angle
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type 2) could be computed with a {cosine} potential. The assignment
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of angle type to style is made via the "angle_coeff"_angle_coeff.html
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command or in the data file.
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In the angle_coeff commands, the name of an angle style must be added
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after the angle type, with the remaining coefficients being those
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appropriate to that style. In the example above, the 2 angle_coeff
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commands set angles of angle type 1 to be computed with a {harmonic}
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potential with coefficients 80.0, 30.0 for K, theta0. All other angle
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types (2-N) are computed with a {cosine} potential with coefficient
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50.0 for K.
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If angle coefficients are specified in the data file read via the
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"read_data"_read_data.html command, then the same rule applies.
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E.g. "harmonic" or "cosine", must be added after the angle type, for each
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line in the "Angle Coeffs" section, e.g.
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Angle Coeffs :pre
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1 harmonic 80.0 30.0
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2 cosine 50.0
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... :pre
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If {class2} is one of the angle hybrid styles, the same rule holds for
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specifying additional BondBond (and BondAngle) coefficients either via
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the input script or in the data file. I.e. {class2} must be added to
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each line after the angle type. For lines in the BondBond (or
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BondAngle) section of the data file for angle types that are not
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{class2}, you must use an angle style of {skip} as a placeholder, e.g.
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BondBond Coeffs :pre
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1 skip
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2 class2 3.6512 1.0119 1.0119
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... :pre
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Note that it is not necessary to use the angle style {skip} in the
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input script, since BondBond (or BondAngle) coefficients need not be
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specified at all for angle types that are not {class2}.
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An angle style of {none} with no additional coefficients can be used
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in place of an angle style, either in a input script angle_coeff
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command or in the data file, if you desire to turn off interactions
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for specific angle types.
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[Restrictions:]
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This angle style can only be used if LAMMPS was built with the
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MOLECULAR package (which it is by default). See the "Making
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LAMMPS"_Section_start.html#start_3 section for more info on packages.
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Unlike other angle styles, the hybrid angle style does not store angle
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coefficient info for individual sub-styles in a "binary restart
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files"_restart.html. Thus when retarting a simulation from a restart
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file, you need to re-specify angle_coeff commands.
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[Related commands:]
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"angle_coeff"_angle_coeff.html
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[Default:] none
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