2007-10-04 23:05:42 +08:00
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"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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compute ackland/atom command :h3
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[Syntax:]
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compute ID group-ID ackland/atom :pre
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ID, group-ID are documented in "compute"_compute.html command
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ackland/atom = style name of this compute command :ul
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[Examples:]
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compute 1 all ackland/atom :pre
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[Description:]
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Defines a computation that calculates the local lattice structure
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2008-01-04 08:56:10 +08:00
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according to the formulation given in "(Ackland)"_#Ackland.
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2007-10-04 23:05:42 +08:00
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In contrast to the "centro-symmetry
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parameter"_compute_centro_atom.html this method is stable against
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temperature boost, because it is based not on the distance between
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particles but the angles. Therefore statistical fluctuations are
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averaged out a little more. A comparison with the Common Neighbor
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2008-01-04 08:56:10 +08:00
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Analysis metric is made in the paper.
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2007-10-04 23:05:42 +08:00
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The result is a number which is mapped to the following different
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lattice structures:
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1 = UNKNOWN
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2 = BCC
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3 = FCC
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4 = HCP
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5 = ICO :ul
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The neighbor list needed to compute this quantity is constructed each
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time the calculation is performed (i.e. each time a snapshot of atoms
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is dumped). Thus it can be inefficient to compute/dump this quantity
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too frequently or to have multiple compute/dump commands, each of
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which computes this quantity.-
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2008-01-04 08:56:10 +08:00
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[Output info:]
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This compute calculates a scalar quantity for each atom, which can be
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accessed by any command that uses per-atom computes as input. See
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"this section"_Section_howto.html#4_15 for an overview of LAMMPS
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output options.
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2008-05-16 06:05:51 +08:00
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[Restrictions:]
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This compute is part of the "user-ackland" package. It is only
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enabled if LAMMPS was built with that package. See the "Making
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LAMMPS"_Section_start.html#2_3 section for more info.
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2007-10-04 23:05:42 +08:00
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[Related commands:]
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"compute centro/atom"_compute_centro_atom.html
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[Default:] none
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:line
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:link(Ackland)
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[(Ackland)] Ackland, Jones, Phys Rev B, 73, 054104 (2006).
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