forked from lijiext/lammps
76 lines
2.6 KiB
HTML
76 lines
2.6 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/asphere 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/asphere
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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/asphere = style name of this compute command
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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/asphere
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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 group of aspherical particles. The aspherical particles can be
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ellipsoids, or line segments, or triangles. See the
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<A HREF = "atom_style.html">atom_style</A> and <A HREF = "read_data.html">read_data</A> commands
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for descriptions of these options.
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</P>
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<P>For all 3 types of particles, the rotational kinetic energy is
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computed as 1/2 I w^2, where I is the inertia tensor for the
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aspherical particle and w is its angular velocity, which is computed
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from its angular momentum if needed.
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</P>
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<P>IMPORTANT NOTE: For <A HREF = "dimension.html">2d models</A>, ellipsoidal particles
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are treated as ellipsoids, not ellipses, meaning their moments of
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inertia will be the same as in 3d.
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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 KE). This value can be
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used by any command that uses a global scalar value from a compute as
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input. See <A HREF = "Section_howto.html#howto_15">Section_howto 15</A> for an
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overview of 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 requires that ellipsoidal particles atoms store a shape
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and quaternion orientation and angular momentum as defined by the
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<A HREF = "atom_style.html">atom_style ellipsoid</A> command.
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</P>
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<P>This compute requires that line segment particles atoms store a length
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and orientation and angular velocity as defined by the <A HREF = "atom_style.html">atom_style
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line</A> command.
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</P>
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<P>This compute requires that triangular particles atoms store a size and
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shape and quaternion orientation and angular momentum as defined by
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the <A HREF = "atom_style.html">atom_style tri</A> command.
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</P>
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<P>All particles in the group must be finite-size. They cannot be point
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particles.
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</P>
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<P><B>Related commands:</B> none
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</P>
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<P><A HREF = "compute_erotate_sphere.html">compute erotate/sphere</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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