.. 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 ` 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) `. In contrast to the :doc:`centro-symmetry parameter ` 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 ` 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 ` 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 ` **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