forked from lijiext/lammps
137 lines
4.4 KiB
Plaintext
137 lines
4.4 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,Commands_all.html)
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:line
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pair_style morse command :h3
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pair_style morse/gpu command :h3
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pair_style morse/omp command :h3
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pair_style morse/opt command :h3
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pair_style morse/smooth/linear command :h3
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pair_style morse/smooth/linear/omp command :h3
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pair_style morse/kk command :h3
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[Syntax:]
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pair_style style args :pre
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style = {morse} or {morse/smooth/linear} or {morse/soft}
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args = list of arguments for a particular style :ul
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{morse} args = cutoff
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cutoff = global cutoff for Morse interactions (distance units)
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{morse/smooth/linear} args = cutoff
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cutoff = global cutoff for Morse interactions (distance units)
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:pre
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[Examples:]
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pair_style morse 2.5
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pair_style morse/smooth/linear 2.5
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pair_coeff * * 100.0 2.0 1.5
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pair_coeff 1 1 100.0 2.0 1.5 3.0 :pre
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[Description:]
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Style {morse} computes pairwise interactions with the formula
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:c,image(Eqs/pair_morse.jpg)
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Rc is the cutoff.
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The following coefficients must be defined for each pair of atoms
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types via the "pair_coeff"_pair_coeff.html command as in the examples
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above, or in the data file or restart files read by the
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"read_data"_read_data.html or "read_restart"_read_restart.html
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commands:
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D0 (energy units)
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alpha (1/distance units)
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r0 (distance units)
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cutoff (distance units) :ul
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The last coefficient is optional. If not specified, the global morse
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cutoff is used.
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:line
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The {morse/smooth/linear} variant is similar to the lj/smooth/linear
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variant in that it adds to the potential a shift and a linear term
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so that both, potential energy and force, go to zero at the cut-off:
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:c,image(Eqs/pair_morse_smooth_linear.jpg)
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The syntax of the pair_style and pair_coeff commands are the same for
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the {morse} and {morse/smooth/linear} styles.
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:line
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A version of the {morse} style with a soft core, {morse/soft}, suitable for use in
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free energy calculations, is part of the USER-FEP package and is documented with
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the "pair_fep_soft"_pair_fep_soft.html styles. The version with soft core is only
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available if LAMMPS was built with that package. See the "Build
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package"_Build_package.html doc page for more info.
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:line
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Styles with a {gpu}, {intel}, {kk}, {omp}, or {opt} suffix are
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functionally the same as the corresponding style without the suffix.
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They have been optimized to run faster, depending on your available
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hardware, as discussed on the "Speed packages"_Speed_packages.html doc
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page. The accelerated styles take the same arguments and should
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produce the same results, except for round-off and precision issues.
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These accelerated styles are part of the GPU, USER-INTEL, KOKKOS,
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USER-OMP and OPT packages, respectively. They are only enabled if
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LAMMPS was built with those packages. See the "Build
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package"_Build_package.html doc page for more info.
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You can specify the accelerated styles explicitly in your input script
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by including their suffix, or you can use the "-suffix command-line
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switch"_Run_options.html when you invoke LAMMPS, or you can use the
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"suffix"_suffix.html command in your input script.
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See the "Speed packages"_Speed_packages.html doc page for more
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instructions on how to use the accelerated styles effectively.
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:line
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[Mixing, shift, table, tail correction, restart, rRESPA info]:
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None of these pair styles support mixing. Thus, coefficients for all
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I,J pairs must be specified explicitly.
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All of these pair styles support the "pair_modify"_pair_modify.html
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shift option for the energy of the pair interaction.
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The "pair_modify"_pair_modify.html table options is not relevant for
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the Morse pair styles.
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None of these pair styles support the "pair_modify"_pair_modify.html
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tail option for adding long-range tail corrections to energy and
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pressure.
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All of these pair styles write their information to "binary restart
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files"_restart.html, so pair_style and pair_coeff commands do not need
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to be specified in an input script that reads a restart file.
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These pair styles can only be used via the {pair} keyword of the
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"run_style respa"_run_style.html command. They do not support the
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{inner}, {middle}, {outer} keywords.
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:line
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[Restrictions:]
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The {morse/smooth/linear} pair style is only enabled if LAMMPS was
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built with the USER-MISC package. See the "Build
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package"_Build_package.html doc page for more info.
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[Related commands:]
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"pair_coeff"_pair_coeff.html, "pair_fep_soft"_pair_fep_soft.html
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[Default:] none
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