"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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bond_style harmonic/shift/cut command :h3
bond_style harmonic/shift/cut/omp command :h3

[Syntax:]

bond_style harmonic/shift/cut :pre

[Examples:]

bond_style harmonic/shift/cut
bond_coeff 5 10.0 0.5 1.0 :pre

[Description:]

The {harmonic/shift/cut} bond style is a shifted harmonic bond that
uses the potential

:c,image(Eqs/bond_harmonic_shift_cut.jpg)

where r0 is the equilibrium bond distance, and rc the critical distance.
The bond potential is zero for distances r > rc. The potential is -Umin
at r0 and zero at rc. The spring constant is k = Umin / \[ 2 (r0-rc)^2\].

The following coefficients must be defined for each bond type via the
"bond_coeff"_bond_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:

Umin (energy)
r0 (distance)
rc (distance) :ul

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Styles with a {cuda}, {gpu}, {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-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 bond 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:]

"bond_coeff"_bond_coeff.html, "delete_bonds"_delete_bonds.html,
"bond_harmonic"_bond_harmonic.html,
"bond_harmonicshift"_bond_harmonicshift.html

[Default:] none
