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

doc/html/_sources/compute_basal_atom.txt

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+.. index:: compute basal/atom
+
+compute basal/atom command
+==========================
+
+Syntax
+""""""
+
+.. parsed-literal::
+
+   compute ID group-ID basal/atom
+
+* ID, group-ID are documented in :doc:`compute <compute>` command
+* basal/atom = style name of this compute command
+
+Examples
+""""""""
+
+.. parsed-literal::
+
+   compute 1 all basal/atom
+
+Description
+"""""""""""
+
+Defines a computation that calculates the hexagonal close-packed "c"
+lattice vector for each atom in the group.  It does this by
+calculating the normal unit vector to the basal plane for each atom.
+The results enable efficient identification and characterization of
+twins and grains in hexagonal close-packed structures.
+
+The output of the compute is thus the 3 components of a unit vector
+associdate with each atom.  The components are set to 0.0 for
+atoms not in the group.
+
+Details of the calculation are given in :ref:`(Barrett) <Barrett>`.
+
+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.
+
+An example input script that uses this compute is provided
+in examples/USER/misc/basal.
+
+**Output info:**
+
+This compute calculates a per-atom array with 3 columns, which can be
+accessed by indices 1-3 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.
+
+The per-atom vector values are unitless since the 3 columns represent
+components of a unit vector.
+
+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 output of this compute will be meaningless unless the atoms are on
+(or near) hcp lattice sites, since the calculation assumes a
+well-defined basal plane.
+
+Related commands
+""""""""""""""""
+
+:doc:`compute centro/atom <compute_centro_atom>`, :doc:`compute ackland/atom <compute_ackland_atom>`
+
+**Default:** none
+
+
+----------
+
+
+.. _Barrett:
+
+
+
+**(Barrett)** Barrett, Tschopp, El Kadiri, Scripta Mat. 66, p.666 (2012).
+
+
+.. _lws: http://lammps.sandia.gov
+.. _ld: Manual.html
+.. _lc: Section_commands.html#comm