forked from lijiext/lammps
67 lines
2.2 KiB
HTML
67 lines
2.2 KiB
HTML
<HTML>
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<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
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<HR>
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<H3>compute erotate/rigid command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>compute ID group-ID erotate/rigid fix-ID
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</PRE>
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<UL><LI>ID, group-ID are documented in <A HREF = "compute.html">compute</A> command
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<LI>erotate/rigid = style name of this compute command
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<LI>fix-ID = ID of rigid body fix
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>compute 1 all erotate/rigid myRigid
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>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 <A HREF = "fix_rigid.html">fix
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rigid</A> command variants.
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</P>
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<P>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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</P>
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<P>The <I>fix-ID</I> should be the ID of one of the <A HREF = "fix_rigid.html">fix rigid</A>
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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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</P>
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<P><B>Output info:</B>
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</P>
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<P>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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<A HREF = "Section_howto.html#howto_15">Section_howto 15</A> for an overview of
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LAMMPS output options.
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</P>
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<P>The scalar value calculated by this compute is "extensive". The
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scalar value will be in energy <A HREF = "units.html">units</A>.
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</P>
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<P><B>Restrictions:</B>
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</P>
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<P>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 <A HREF = "Section_start.html#start_3">Making
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LAMMPS</A> section for more info.
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "compute_erotate_ke_rigid.html">compute ke/rigid</A>
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</P>
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<P><B>Default:</B> none
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</P>
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</HTML>
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