compute ackland/atom command
compute ID group-ID ackland/atom
- ID, group-ID are documented in compute command
- ackland/atom = style name of this compute command
compute 1 all ackland/atom
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:
- 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.-
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 Section 6.15 for an overview of LAMMPS output options.
This compute is part of the USER-MISC package. It is only enabled if LAMMPS was built with that package. See the Making LAMMPS section for more info.
The per-atom vector values will be unitless since they are the integers defined above.