Syntax:
compute ID group-ID ackland/atom
Examples:
compute 1 all ackland/atom
Description:
Defines a computation that calculates the local lattice structure according to the formulation given in (Ackland).
In contrast to the 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:
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 scalar quantity for each atom, which can be accessed by any command that uses per-atom computes as input. See this section for an overview of LAMMPS output options.
Restrictions: none
Related commands:
Default: none
(Ackland) Ackland, Jones, Phys Rev B, 73, 054104 (2006).