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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@1612 f3b2605a-c512-4ea7-a41b-209d697bcdaa
parent 12cba76c

doc/compute_erotate_sphere.html

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<HTML>

<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> 

</CENTER>













<HR>



<H3>compute rotate/dipole command 

</H3>

<P><B>Syntax:</B>

</P>

<PRE>compute ID group-ID rotate/dipole 

</PRE>

<UL><LI>ID, group-ID are documented in <A HREF = "compute.html">compute</A> command

<LI>rotate/dipole = style name of this compute command 

</UL>

<P><B>Examples:</B>

</P>

<PRE>compute 1 all rotate/dipole 

</PRE>

<P><B>Description:</B>

</P>

<P>Define a computation that calculates the total rotational energy of a

group of atoms with point dipole moments.

</P>

<P>The rotational energy is calculated as the sum of 1/2 I w^2 over all

the atoms in the group, where I is the moment of inertia of a

disk/spherical (2d/3d) particle, and w is its angular velocity.

</P>

<P><B>Output info:</B>

</P>

<P>The scalar value calculated by this compute is "extensive", meaning it

it scales with the number of atoms in the simulation.

</P>

<P><B>Restrictions:</B> none

</P>

<P><B>Related commands:</B> none

</P>

<P><B>Default:</B> none

</P>

</HTML>

doc/compute_erotate_sphere.txt

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"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c



:link(lws,http://lammps.sandia.gov)

:link(ld,Manual.html)

:link(lc,Section_commands.html#comm)



:line



compute rotate/dipole command :h3



[Syntax:]



compute ID group-ID rotate/dipole :pre



ID, group-ID are documented in "compute"_compute.html command

rotate/dipole = style name of this compute command :ul



[Examples:]



compute 1 all rotate/dipole :pre



[Description:]



Define a computation that calculates the total rotational energy of a

group of atoms with point dipole moments.



The rotational energy is calculated as the sum of 1/2 I w^2 over all

the atoms in the group, where I is the moment of inertia of a

disk/spherical (2d/3d) particle, and w is its angular velocity.



[Output info:]



The scalar value calculated by this compute is "extensive", meaning it

it scales with the number of atoms in the simulation.



[Restrictions:] none



[Related commands:] none



[Default:] none

doc/compute_temp_sphere.html

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<HTML>

<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> 

</CENTER>













<HR>



<H3>compute temp/sphere command 

</H3>

<P><B>Syntax:</B>

</P>

<PRE>compute ID group-ID temp/sphere 

</PRE>

<UL><LI>ID, group-ID are documented in <A HREF = "compute.html">compute</A> command

<LI>temp/sphere = style name of this compute command 

</UL>

<P><B>Examples:</B>

</P>

<PRE>compute 1 all temp/sphere

compute myTemp mobile temp/sphere 

</PRE>

<P><B>Description:</B>

</P>

<P>Define a computation that calculates the temperature of a group of

spherical particles, including a contribution from both their

translational and rotational kinetic energy.  This differs from the

usual "compute temp" command which assumes point particles with only

translational kinetic energy.

</P>

<P>For 3d spherical particles, each has 6 degrees of freedom (3

translational, 3 rotational).  For 2d spherical particles, each has 3

degrees of freedom (2 translational, 1 rotational).

</P>

<P>The rotational kinetic energy is computed as 1/2 I w^2, where I is the

moment of inertia for a sphere and w is the particle's angular

velocity.

</P>

<P>IMPORTANT NOTE: For a <A HREF = "dimension.html">2-dimensional system</A>, particles

are treated as spheres, not disks.

</P>

<P>A 6-component kinetic energy tensor is also calculated by this

compute.  The formula for the components of the tensor is the same as

the above formula, except that v^2 and w^2 are replaced by vx*vy and

wx*wy for the xy component.

</P>

<P>The number of atoms contributing to the temperature is assumed to be

constant for the duration of the run; use the <I>dynamic</I> option of the

<A HREF = "compute_modify.html">compute_modify</A> command if this is not the case.

</P>

<P>This compute subtracts out translational degrees-of-freedom due to

fixes that constrain molecular motion, such as <A HREF = "fix_shake.html">fix

shake</A> and <A HREF = "fix_rigid.html">fix rigid</A>.  This means the

temperature of groups of atoms that include these constraints will be

computed correctly.  If needed, the subtracted degrees-of-freedom can

be altered using the <I>extra</I> option of the

<A HREF = "compute_modify.html">compute_modify</A> command.

</P>

<P><B>Output info:</B>

</P>

<P>The scalar value calculated by this compute is "intensive", meaning it

is independent of the number of atoms in the simulation.  The vector

values are "extensive", meaning they scale with the number of atoms in

the simulation.

</P>

<P><B>Restrictions:</B>

</P>

<P>This compute requires that particles be represented as extended

spheres and not point particles.  This means they will have an angular

velocity and a diameter which is determined either by the

<A HREF = "shape.html">shape</A> command or by each particle being assigned an

individual radius, e.g. for <A HREF = "atom_style.html">atom_style granular</A>.

</P>

<P><B>Related commands:</B>

</P>

<P><A HREF = "compute_temp.html">compute temp</A>, <A HREF = "compute_temp.html">compute

temp/asphere</A>

</P>

<P><B>Default:</B> none

</P>

</HTML>

doc/compute_temp_sphere.txt

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"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c



:link(lws,http://lammps.sandia.gov)

:link(ld,Manual.html)

:link(lc,Section_commands.html#comm)



:line



compute temp/sphere command :h3



[Syntax:]



compute ID group-ID temp/sphere :pre



ID, group-ID are documented in "compute"_compute.html command

temp/sphere = style name of this compute command :ul



[Examples:]



compute 1 all temp/sphere

compute myTemp mobile temp/sphere :pre



[Description:]



Define a computation that calculates the temperature of a group of

spherical particles, including a contribution from both their

translational and rotational kinetic energy.  This differs from the

usual "compute temp" command which assumes point particles with only

translational kinetic energy.



For 3d spherical particles, each has 6 degrees of freedom (3

translational, 3 rotational).  For 2d spherical particles, each has 3

degrees of freedom (2 translational, 1 rotational).



The rotational kinetic energy is computed as 1/2 I w^2, where I is the

moment of inertia for a sphere and w is the particle's angular

velocity.



IMPORTANT NOTE: For a "2-dimensional system"_dimension.html, particles

are treated as spheres, not disks.



A 6-component kinetic energy tensor is also calculated by this

compute.  The formula for the components of the tensor is the same as

the above formula, except that v^2 and w^2 are replaced by vx*vy and

wx*wy for the xy component.



The number of atoms contributing to the temperature is assumed to be

constant for the duration of the run; use the {dynamic} option of the

"compute_modify"_compute_modify.html command if this is not the case.



This compute subtracts out translational degrees-of-freedom due to

fixes that constrain molecular motion, such as "fix

shake"_fix_shake.html and "fix rigid"_fix_rigid.html.  This means the

temperature of groups of atoms that include these constraints will be

computed correctly.  If needed, the subtracted degrees-of-freedom can

be altered using the {extra} option of the

"compute_modify"_compute_modify.html command.



[Output info:]



The scalar value calculated by this compute is "intensive", meaning it

is independent of the number of atoms in the simulation.  The vector

values are "extensive", meaning they scale with the number of atoms in

the simulation.



[Restrictions:]



This compute requires that particles be represented as extended

spheres and not point particles.  This means they will have an angular

velocity and a diameter which is determined either by the

"shape"_shape.html command or by each particle being assigned an

individual radius, e.g. for "atom_style granular"_atom_style.html.



[Related commands:]



"compute temp"_compute_temp.html, "compute

temp/asphere"_compute_temp.html



[Default:] none

doc/fix_nve_sphere.html

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<HTML>

<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> 

</CENTER>













<HR>



<H3>fix nve/asphere command 

</H3>

<P><B>Syntax:</B>

</P>

<PRE>fix ID group-ID nve/asphere 

</PRE>

<UL><LI>ID, group-ID are documented in <A HREF = "fix.html">fix</A> command

<LI>nve/asphere = style name of this fix command 

</UL>

<P><B>Examples:</B>

</P>

<PRE>fix 1 all nve/asphere 

</PRE>

<P><B>Description:</B>

</P>

<P>Perform constant NVE updates of position, velocity, orientation, and

angular velocity for aspherical or ellipsoidal particles in the group

each timestep.  V is volume; E is energy.  This creates a system

trajectory consistent with the microcanonical ensemble.

</P>

<P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>

</P>

<P>No information about this fix is written to <A HREF = "restart.html">binary restart

files</A>.  None of the <A HREF = "fix_modify.html">fix_modify</A> options

are relevant to this fix.  No global scalar or vector or per-atom

quantities are stored by this fix for access by various <A HREF = "Section_howto.html#4_15">output

commands</A>.  No parameter of this fix can be

used with the <I>start/stop</I> keywords of the <A HREF = "run.html">run</A> command.

This fix is not invoked during <A HREF = "minimize.html">energy minimization</A>.

</P>

<P><B>Restrictions:</B> 

</P>

<P>This fix is part of the "asphere" package.  It is only enabled if

LAMMPS was built with that package.  See the <A HREF = "Section_start.html#2_3">Making

LAMMPS</A> section for more info.

</P>

<P><B>Related commands:</B>

</P>

<P><A HREF = "fix_nve.html">fix nve</A>

</P>

<P><B>Default:</B> none

</P>

</HTML>

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