forked from lijiext/lammps
71 lines
2.4 KiB
Plaintext
71 lines
2.4 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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improper_style hybrid command :h3
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[Syntax:]
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improper_style hybrid style1 style2 ... :pre
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style1,style2 = list of one or more improper styles :ul
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[Examples:]
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improper_style hybrid harmonic helix
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improper_coeff 1 harmonic 120.0 30
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improper_coeff 2 cvff 20.0 -1 2 :pre
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[Description:]
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The {hybrid} style enables the use of multiple improper styles in one
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simulation. An improper style is assigned to each improper type. For
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example, impropers in a polymer flow (of improper type 1) could be
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computed with a {harmonic} potential and impropers in the wall
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boundary (of improper type 2) could be computed with a {cvff}
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potential. The assignment of improper type to style is made via the
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"improper_coeff"_improper_coeff.html command or in the data file.
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In the improper_coeff command, the first coefficient sets the improper
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style and the remaining coefficients are those appropriate to that
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style. In the example above, the 2 improper_coeff commands would set
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impropers of improper type 1 to be computed with a {harmonic}
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potential with coefficients 120.0, 30 for K, X0. Improper type 2
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would be computed with a {cvff} potential with coefficients 20.0, -1,
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2 for K, d, n.
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If the improper {class2} potential is one of the hybrid styles, it
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requires additional AngleAngle coefficients be specified in the data
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file. These lines must also have an additional "class2" argument
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added after the improper type. For improper types which are assigned
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to other hybrid styles, use the style name (e.g. "harmonic")
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appropriate to that style. The AngleAngle coeffs for that improper
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type will then be ignored.
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An improper style of {none} can be specified as the 2nd argument to
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the improper_coeff command, if you desire to turn off certain improper
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types.
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:line
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[Restrictions:]
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This improper 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 improper styles, the hybrid improper style does not store
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improper coefficient info for individual sub-styles in a "binary
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restart files"_restart.html. Thus when retarting a simulation from a
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restart file, you need to re-specify improper_coeff commands.
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[Related commands:]
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"improper_coeff"_improper_coeff.html
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[Default:] none
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