forked from lijiext/lammps
87 lines
2.9 KiB
Plaintext
87 lines
2.9 KiB
Plaintext
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"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_coeff command :h3
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[Syntax:]
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improper_coeff N args :pre
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N = improper type (see asterik form below)
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args = coefficients for one or more improper types :ul
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[Examples:]
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improper_coeff 1 300.0 0.0
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improper_coeff * 80.2 -1 2
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improper_coeff *4 80.2 -1 2 :pre
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[Description:]
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Specify the improper force field coefficients for one or more improper
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types. The number and meaning of the coefficients depends on the
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improper style. Improper coefficients can also be set in the data
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file read by the "read_data"_read_data.html command or in a restart
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file.
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N can be specified in one of two ways. An explicit numeric value can
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be used, as in the 1st example above. Or a wild-card asterik can be
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used to set the coefficients for multiple improper types. This takes
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the form "*" or "*n" or "n*" or "m*n". If N = the number of improper
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types, then an asterik with no numeric values means all types from 1
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to N. A leading asterik means all types from 1 to n (inclusive). A
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trailing asterik means all types from n to N (inclusive). A middle
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asterik means all types from m to n (inclusive).
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Note that using a improper_coeff command can override a previous
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setting for the same improper type. For example, these commands set
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the coeffs for all improper types, then overwrite the coeffs for just
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improper type 2:
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improper_coeff * 300.0 0.0
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improper_coeff 2 50.0 0.0 :pre
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A line in a data file that specifies improper coefficients uses the
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exact same format as the arguments of the improper_coeff command in an
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input script, except that wild-card asteriks should not be used since
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coefficients for all N types must be listed in the file. For example,
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under the "Improper 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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1 300.0 0.0 :pre
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:line
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Here is an alphabetic list of improper 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 "improper_coeff"_improper_coeff.html command:
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"improper_style none"_improper_style_none.html - turn off improper interactions
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"improper_style hybrid"_improper_style_hybrid.html - define multiple styles of improper interactions :ul
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"improper_style class2"_improper_style_class2.html - COMPASS (class 2) improper
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"improper_style cvff"_improper_style_cvff.html - CVFF improper
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"improper_style harmonic"_improper_style_harmonic.html - harmonic improper :ul
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:line
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[Restrictions:]
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This command must come after the simulation box is defined by a
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"read_data"_read_data.html, "read_restart"_read_restart.html, or
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"create_box"_create_box.html command.
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An improper style must be defined before any improper coefficients are
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set, either in the input script or in a data file.
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[Related commands:]
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"improper_style"_improper_style.html
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[Default:] none
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