forked from lijiext/lammps
82 lines
2.6 KiB
HTML
82 lines
2.6 KiB
HTML
|
<HTML>
|
||
|
|
<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
|
||
|
|
</CENTER>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<HR>
|
||
|
|
|
||
|
|
<H3>bond_style harmonic command
|
||
|
|
</H3>
|
||
|
|
<H3>bond_style harmonic/kk command
|
||
|
|
</H3>
|
||
|
|
<H3>bond_style harmonic/omp command
|
||
|
|
</H3>
|
||
|
|
<P><B>Syntax:</B>
|
||
|
|
</P>
|
||
|
|
<PRE>bond_style harmonic
|
||
|
|
</PRE>
|
||
|
|
<P><B>Examples:</B>
|
||
|
|
</P>
|
||
|
|
<PRE>bond_style harmonic
|
||
|
|
bond_coeff 5 80.0 1.2
|
||
|
|
</PRE>
|
||
|
|
<P><B>Description:</B>
|
||
|
|
</P>
|
||
|
|
<P>The <I>harmonic</I> bond style uses the potential
|
||
|
|
</P>
|
||
|
|
<CENTER><IMG SRC = "Eqs/bond_harmonic.jpg">
|
||
|
|
</CENTER>
|
||
|
|
<P>where r0 is the equilibrium bond distance. Note that the usual 1/2
|
||
|
|
factor is included in K.
|
||
|
|
</P>
|
||
|
|
<P>The following coefficients must be defined for each bond type via the
|
||
|
|
<A HREF = "bond_coeff.html">bond_coeff</A> command as in the example above, or in
|
||
|
|
the data file or restart files read by the <A HREF = "read_data.html">read_data</A>
|
||
|
|
or <A HREF = "read_restart.html">read_restart</A> commands:
|
||
|
|
</P>
|
||
|
|
<UL><LI>K (energy/distance^2)
|
||
|
|
<LI>r0 (distance)
|
||
|
|
</UL>
|
||
|
|
<HR>
|
||
|
|
|
||
|
|
<P>Styles with a <I>cuda</I>, <I>gpu</I>, <I>intel</I>, <I>kk</I>, <I>omp</I>, or <I>opt</I> 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 <A HREF = "Section_accelerate.html">Section_accelerate</A>
|
||
|
|
of the manual. The accelerated styles take the same arguments and
|
||
|
|
should produce the same results, except for round-off and precision
|
||
|
|
issues.
|
||
|
|
</P>
|
||
|
|
<P>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 <A HREF = "Section_start.html#start_3">Making
|
||
|
|
LAMMPS</A> section for more info.
|
||
|
|
</P>
|
||
|
|
<P>You can specify the accelerated styles explicitly in your input script
|
||
|
|
by including their suffix, or you can use the <A HREF = "Section_start.html#start_7">-suffix command-line
|
||
|
|
switch</A> when you invoke LAMMPS, or you can
|
||
|
|
use the <A HREF = "suffix.html">suffix</A> command in your input script.
|
||
|
|
</P>
|
||
|
|
<P>See <A HREF = "Section_accelerate.html">Section_accelerate</A> of the manual for
|
||
|
|
more instructions on how to use the accelerated styles effectively.
|
||
|
|
</P>
|
||
|
|
<HR>
|
||
|
|
|
||
|
|
<P><B>Restrictions:</B>
|
||
|
|
</P>
|
||
|
|
<P>This bond style can only be used if LAMMPS was built with the
|
||
|
|
MOLECULE package (which it is by default). See the <A HREF = "Section_start.html#start_3">Making
|
||
|
|
LAMMPS</A> section for more info on packages.
|
||
|
|
</P>
|
||
|
|
<P><B>Related commands:</B>
|
||
|
|
</P>
|
||
|
|
<P><A HREF = "bond_coeff.html">bond_coeff</A>, <A HREF = "delete_bonds.html">delete_bonds</A>
|
||
|
|
</P>
|
||
|
|
<P><B>Default:</B> none
|
||
|
|
</P>
|
||
|
|
</HTML>
|