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

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

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improper_style fourier command :h3
improper_style fourier/omp command :h3

[Syntax:]

improper_style fourier :pre

[Examples:]

improper_style fourier
improper_coeff 1 100.0 180.0 :pre

[Description:]

The {fourier} improper style uses the following potential:

:c,image(Eqs/improper_fourier.jpg)

where K is the force constant and omega is the angle between the IL
axis and the IJK plane:

:c,image(Eqs/umbrella.jpg)

If all parameter (see bellow) is not zero, the all the three possible angles will taken in account.

The following coefficients must be defined for each improper type via
the "improper_coeff"_improper_coeff.html command as in the example
above, or in the data file or restart files read by the
"read_data"_read_data.html or "read_restart"_read_restart.html
commands:

K (energy)
C0 (real)
C1 (real)
C2 (real)
all  (integer >= 0) :ul

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Styles with a {cuda}, {gpu}, {intel}, {kk}, {omp}, or {opt} suffix are
functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
hardware, as discussed in "Section_accelerate"_Section_accelerate.html
of the manual.  The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.

These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
KOKKOS, USER-OMP and OPT packages, respectively.  They are only
enabled if LAMMPS was built with those packages.  See the "Making
LAMMPS"_Section_start.html#start_3 section for more info.

You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the "-suffix command-line
switch"_Section_start.html#start_7 when you invoke LAMMPS, or you can
use the "suffix"_suffix.html command in your input script.

See "Section_accelerate"_Section_accelerate.html of the manual for
more instructions on how to use the accelerated styles effectively.

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[Restrictions:]

This angle style can only be used if LAMMPS was built with the
USER_MISC package.  See the "Making LAMMPS"_Section_start.html#start_3 
section for more info on packages.

[Related commands:]

"improper_coeff"_improper_coeff.html

[Default:] none

