forked from lijiext/lammps
78 lines
2.2 KiB
HTML
78 lines
2.2 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>compute ackland/atom command
|
|
</H3>
|
|
<P><B>Syntax:</B>
|
|
</P>
|
|
<PRE>compute ID group-ID ackland/atom
|
|
</PRE>
|
|
<UL><LI>ID, group-ID are documented in <A HREF = "compute.html">compute</A> command
|
|
<LI>ackland/atom = style name of this compute command
|
|
</UL>
|
|
<P><B>Examples:</B>
|
|
</P>
|
|
<PRE>compute 1 all ackland/atom
|
|
</PRE>
|
|
<P><B>Description:</B>
|
|
</P>
|
|
<P>Defines a computation that calculates the local lattice structure
|
|
according to the formulation given in <A HREF = "#Ackland">(Ackland)</A>.
|
|
</P>
|
|
<P>In contrast to the <A HREF = "compute_centro_atom.html">centro-symmetry
|
|
parameter</A> this method is stable against
|
|
temperature boost, because it is based not on the distance between
|
|
particles but the angles. Therefore statistical fluctuations are
|
|
averaged out a little more. A comparison with the Common Neighbor
|
|
Analysis metric is made in the paper.
|
|
</P>
|
|
<P>The result is a number which is mapped to the following different
|
|
lattice structures:
|
|
</P>
|
|
<UL><LI>0 = UNKNOWN
|
|
<LI>1 = BCC
|
|
<LI>2 = FCC
|
|
<LI>3 = HCP
|
|
<LI>4 = ICO
|
|
</UL>
|
|
<P>The neighbor list needed to compute this quantity is constructed each
|
|
time the calculation is performed (i.e. each time a snapshot of atoms
|
|
is dumped). Thus it can be inefficient to compute/dump this quantity
|
|
too frequently or to have multiple compute/dump commands, each of
|
|
which computes this quantity.-
|
|
</P>
|
|
<P><B>Output info:</B>
|
|
</P>
|
|
<P>This compute calculates a scalar quantity for each atom, which can be
|
|
accessed by any command that uses per-atom values from a compute as
|
|
input. See <A HREF = "Section_howto.html#4_15">this section</A> for an overview of
|
|
LAMMPS output options.
|
|
</P>
|
|
<P><B>Restrictions:</B>
|
|
</P>
|
|
<P>This compute is part of the "user-misc" package. It is only enabled
|
|
if LAMMPS was built with that package. See the <A HREF = "Section_start.html#2_3">Making
|
|
LAMMPS</A> section for more info.
|
|
</P>
|
|
<P><B>Related commands:</B>
|
|
</P>
|
|
<P><A HREF = "compute_centro_atom.html">compute centro/atom</A>
|
|
</P>
|
|
<P><B>Default:</B> none
|
|
</P>
|
|
<HR>
|
|
|
|
<A NAME = "Ackland"></A>
|
|
|
|
<P><B>(Ackland)</B> Ackland, Jones, Phys Rev B, 73, 054104 (2006).
|
|
</P>
|
|
</HTML>
|