forked from lijiext/lammps
70 lines
1.9 KiB
Plaintext
70 lines
1.9 KiB
Plaintext
.. index:: compute erotate/rigid
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compute erotate/rigid command
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=============================
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Syntax
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""""""
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.. parsed-literal::
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compute ID group-ID erotate/rigid fix-ID
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* ID, group-ID are documented in :doc:`compute <compute>` command
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* erotate/rigid = style name of this compute command
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* fix-ID = ID of rigid body fix
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Examples
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""""""""
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.. parsed-literal::
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compute 1 all erotate/rigid myRigid
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Description
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"""""""""""
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Define a computation that calculates the rotational kinetic energy of
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a collection of rigid bodies, as defined by one of the :doc:`fix rigid <fix_rigid>` command variants.
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The rotational energy of each rigid body is computed as 1/2 I Wbody^2,
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where I is the inertia tensor for the rigid body, and Wbody is its
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angular velocity vector. Both I and Wbody are in the frame of
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reference of the rigid body, i.e. I is diagonalized.
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The *fix-ID* should be the ID of one of the :doc:`fix rigid <fix_rigid>`
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commands which defines the rigid bodies. The group specified in the
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compute command is ignored. The rotational energy of all the rigid
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bodies defined by the fix rigid command in included in the
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calculation.
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**Output info:**
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This compute calculates a global scalar (the summed rotational energy
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of all the rigid bodies). This value can be used by any command that
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uses a global scalar value from a compute as input. See
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:ref:`Section_howto 15 <howto_15>` for an overview of
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LAMMPS output options.
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The scalar value calculated by this compute is "extensive". The
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scalar value will be in energy :doc:`units <units>`.
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Restrictions
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""""""""""""
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This compute is part of the RIGID package. It is only enabled if
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LAMMPS was built with that package. See the :ref:`Making LAMMPS <start_3>` section for more info.
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Related commands
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""""""""""""""""
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:doc:`compute ke/rigid <compute_erotate_ke_rigid>`
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**Default:** none
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.. _lws: http://lammps.sandia.gov
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.. _ld: Manual.html
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.. _lc: Section_commands.html#comm
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