forked from lijiext/lammps
71 lines
2.4 KiB
Plaintext
71 lines
2.4 KiB
Plaintext
"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 inertia/molecule command :h3
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[Syntax:]
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compute ID group-ID inertia/molecule :pre
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ID, group-ID are documented in "compute"_compute.html command
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inertia/molecule = style name of this compute command :ul
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[Examples:]
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compute 1 fluid inertia/molecule :pre
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[Description:]
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Define a computation that calculates the inertia tensor of individual
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molecules. The calculation includes all effects due to atoms passing
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thru periodic boundaries.
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The symmetric intertia tensor has 6 components, ordered
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Ixx,Iyy,Izz,Ixy,Iyz,Ixz. The tensor for a particular molecule is only
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computed if one or more of its atoms is in the specified group.
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Normally all atoms in the molecule should be in the group, however
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this is not required. LAMMPS will warn you if this is not the case.
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Only atoms in the group contribute to the inertia tensor and
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associated center-of-mass calculation for the molecule.
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The ordering of per-molecule quantities produced by this compute is
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consistent with the ordering produced by other compute commands that
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generate per-molecule datums. Conceptually, the molecule IDs will be
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in ascending order for any molecule with one or more of its atoms in
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the specified group.
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IMPORTANT NOTE: The coordinates of an atom contribute to the
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molecule's inertia tensor in "unwrapped" form, by using the image
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flags associated with each atom. See the "dump custom"_dump.html
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command for a discussion of "unwrapped" coordinates. See the Atoms
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section of the "read_data"_read_data.html command for a discussion of
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image flags and how they are set for each atom. You can reset the
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image flags (e.g. to 0) before invoking this compute by using the "set
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image"_set.html command.
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[Output info:]
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This compute calculates a global array where the number of rows =
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Nmolecules and the number of columns = 6 for the 6 components of the
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inertia tensor of each molecule, ordered as listed above. These
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values can be accessed by any command that uses global array values
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from a compute as input. See "Section_howto
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15"_Section_howto.html#howto_15 for an overview of LAMMPS output
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options.
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The array values are "intensive". The array values will be in
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distance "units"_units.html.
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[Restrictions:] none
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[Related commands:]
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"variable inertia() function"_variable.html
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[Default:] none
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