git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@14950 f3b2605a-c512-4ea7-a41b-209d697bcdaa

doc/html/_sources/compute_ackland_atom.txt

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+.. index:: compute ackland/atom
+
+compute ackland/atom command
+============================
+
+Syntax
+""""""
+
+.. parsed-literal::
+
+   compute ID group-ID ackland/atom
+
+* ID, group-ID are documented in :doc:`compute <compute>` command
+* ackland/atom = style name of this compute command
+
+Examples
+""""""""
+
+.. parsed-literal::
+
+   compute 1 all ackland/atom
+
+Description
+"""""""""""
+
+Defines a computation that calculates the local lattice structure
+according to the formulation given in :ref:`(Ackland) <Ackland>`.
+
+In contrast to the :doc:`centro-symmetry parameter <compute_centro_atom>` 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.
+
+The result is a number which is mapped to the following different
+lattice structures:
+
+* 0 = UNKNOWN
+* 1 = BCC
+* 2 = FCC
+* 3 = HCP
+* 4 = ICO
+
+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.-
+
+**Output info:**
+
+This compute calculates a per-atom vector, which can be accessed by
+any command that uses per-atom values from a compute as input.  See
+:ref:`Section_howto 15 <howto_15>` for an overview of
+LAMMPS output options.
+
+Restrictions
+""""""""""""
+
+
+This compute is part of the USER-MISC package.  It is only enabled if
+LAMMPS was built with that package.  See the :ref:`Making LAMMPS <start_3>` section for more info.
+
+The per-atom vector values will be unitless since they are the
+integers defined above.
+
+Related commands
+""""""""""""""""
+
+:doc:`compute centro/atom <compute_centro_atom>`
+
+**Default:** none
+
+
+----------
+
+
+.. _Ackland:
+
+
+
+**(Ackland)** Ackland, Jones, Phys Rev B, 73, 054104 (2006).
+
+
+.. _lws: http://lammps.sandia.gov
+.. _ld: Manual.html
+.. _lc: Section_commands.html#comm