git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@8272 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp
2012-06-13 16:02:51 +00:00
parent ee74e0f713
commit e8fac9300b
4 changed files with 83 additions and 29 deletions

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@ -36,6 +36,12 @@ this formula
<P>where M is the total mass of the group, Rcm is the center-of-mass <P>where M is the total mass of the group, Rcm is the center-of-mass
position of the group, and the sum is over all atoms in the group. position of the group, and the sum is over all atoms in the group.
</P> </P>
<P>A Rg tensor, stored as a 6-element vector, is also calculated by this
compute. The formula for the components of the tensor is the same as
the above formula, except that (Ri - Rcm)^2 is replaced by (Rix -
Rcmx) * (Riy - Rcmy) for the xy component, etc. The 6 components of
the vector are ordered xx, yy, zz, xy, xz, yz.
</P>
<P>IMPORTANT NOTE: The coordinates of an atom contribute to Rg in <P>IMPORTANT NOTE: The coordinates of an atom contribute to Rg in
"unwrapped" form, by using the image flags associated with each atom. "unwrapped" form, by using the image flags associated with each atom.
See the <A HREF = "dump.html">dump custom</A> command for a discussion of See the <A HREF = "dump.html">dump custom</A> command for a discussion of
@ -47,13 +53,16 @@ image</A> command.
</P> </P>
<P><B>Output info:</B> <P><B>Output info:</B>
</P> </P>
<P>This compute calculates a global scalar (Rg). This value can be used <P>This compute calculates a global scalar (Rg) and a global vector of
by any command that uses a global scalar value from a compute as length 6 (Rg tensor), which can be accessed by indices 1-6. These
input. See <A HREF = "Section_howto.html#howto_15">Section_howto 15</A> for an values can be used by any command that uses a global scalar value or
overview of LAMMPS output options. vector values from a compute as input. See <A HREF = "Section_howto.html#howto_15">Section_howto
15</A> for an overview of LAMMPS output
options.
</P> </P>
<P>The scalar value calculated by this compute is "intensive". The <P>The scalar and vector values calculated by this compute are
scalar value will be in distance <A HREF = "units.html">units</A>. "intensive". The scalar and vector values will be in distance
<A HREF = "units.html">units</A>.
</P> </P>
<P><B>Restrictions:</B> none <P><B>Restrictions:</B> none
</P> </P>

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@ -33,6 +33,12 @@ this formula
where M is the total mass of the group, Rcm is the center-of-mass where M is the total mass of the group, Rcm is the center-of-mass
position of the group, and the sum is over all atoms in the group. position of the group, and the sum is over all atoms in the group.
A Rg tensor, stored as a 6-element vector, is also calculated by this
compute. The formula for the components of the tensor is the same as
the above formula, except that (Ri - Rcm)^2 is replaced by (Rix -
Rcmx) * (Riy - Rcmy) for the xy component, etc. The 6 components of
the vector are ordered xx, yy, zz, xy, xz, yz.
IMPORTANT NOTE: The coordinates of an atom contribute to Rg in IMPORTANT NOTE: The coordinates of an atom contribute to Rg in
"unwrapped" form, by using the image flags associated with each atom. "unwrapped" form, by using the image flags associated with each atom.
See the "dump custom"_dump.html command for a discussion of See the "dump custom"_dump.html command for a discussion of
@ -44,13 +50,16 @@ image"_set.html command.
[Output info:] [Output info:]
This compute calculates a global scalar (Rg). This value can be used This compute calculates a global scalar (Rg) and a global vector of
by any command that uses a global scalar value from a compute as length 6 (Rg tensor), which can be accessed by indices 1-6. These
input. See "Section_howto 15"_Section_howto.html#howto_15 for an values can be used by any command that uses a global scalar value or
overview of LAMMPS output options. vector values from a compute as input. See "Section_howto
15"_Section_howto.html#howto_15 for an overview of LAMMPS output
options.
The scalar value calculated by this compute is "intensive". The The scalar and vector values calculated by this compute are
scalar value will be in distance "units"_units.html. "intensive". The scalar and vector values will be in distance
"units"_units.html.
[Restrictions:] none [Restrictions:] none

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@ -13,14 +13,23 @@
</H3> </H3>
<P><B>Syntax:</B> <P><B>Syntax:</B>
</P> </P>
<PRE>compute ID group-ID gyration/molecule <PRE>compute ID group-ID gyration/molecule keyword value ...
</PRE> </PRE>
<UL><LI>ID, group-ID are documented in <A HREF = "compute.html">compute</A> command <UL><LI>ID, group-ID are documented in <A HREF = "compute.html">compute</A> command
<LI>gyration/molecule = style name of this compute command <LI>gyration/molecule = style name of this compute command
<LI>zero or more keyword/value pairs may be appended
<LI>keyword = <I>tensor</I>
<I>tensor</I> value = none
</UL> </UL>
<P><B>Examples:</B> <P><B>Examples:</B>
</P> </P>
<PRE>compute 1 molecule gyration/molecule <PRE>compute 1 molecule gyration/molecule
compute 2 molecule gyration/molecule tensor
</PRE> </PRE>
<P><B>Description:</B> <P><B>Description:</B>
</P> </P>
@ -37,6 +46,13 @@ formula
position of the molecule, and the sum is over all atoms in the position of the molecule, and the sum is over all atoms in the
molecule and in the group. molecule and in the group.
</P> </P>
<P>If the <I>tensor</I> keyword is specified, then the scalar Rg value is not
calculated, but an Rg tensor is instead calculated for each molecule.
The formula for the components of the tensor is the same as the above
formula, except that (Ri - Rcm)^2 is replaced by (Rix - Rcmx) * (Riy -
Rcmy) for the xy component, etc. The 6 components of the tensor are
ordered xx, yy, zz, xy, xz, yz.
</P>
<P>Rg for a particular molecule is only computed if one or more of its <P>Rg for a particular molecule is only computed if one or more of its
atoms are in the specified group. Normally all atoms in the molecule atoms are in the specified group. Normally all atoms in the molecule
should be in the group, however this is not required. LAMMPS will should be in the group, however this is not required. LAMMPS will
@ -60,14 +76,18 @@ image</A> command.
</P> </P>
<P><B>Output info:</B> <P><B>Output info:</B>
</P> </P>
<P>This compute calculates a global vector of Rg values where the length <P>This compute calculates a global vector if the <I>tensor</I> keyword is not
of the vector = Nmolecules. These values can be used by any command specified and a global array if it is. The length of the vector or
that uses global vector values from a compute as input. See <A HREF = "Section_howto.html#howto_15">this number of rows in the array is the number of molecules. If the
<I>tensor</I> keyword is specified, the global array has 6 columns. The
vector or array can be accessed by any command that uses global values
from a compute as input. See <A HREF = "Section_howto.html#howto_15">this
section</A> for an overview of LAMMPS output section</A> for an overview of LAMMPS output
options. options.
</P> </P>
<P>The vector values calculated by this compute are "intensive". The <P>All the vector or array values calculated by this compute are
vector values will be in distance <A HREF = "units.html">units</A>. "intensive". The vector or array values will be in distance
<A HREF = "units.html">units</A>.
</P> </P>
<P><B>Restrictions:</B> none <P><B>Restrictions:</B> none
</P> </P>

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@ -10,14 +10,19 @@ compute gyration/molecule command :h3
[Syntax:] [Syntax:]
compute ID group-ID gyration/molecule :pre compute ID group-ID gyration/molecule keyword value ... :pre
ID, group-ID are documented in "compute"_compute.html command ID, group-ID are documented in "compute"_compute.html command :ulb,l
gyration/molecule = style name of this compute command :ul gyration/molecule = style name of this compute command :l
zero or more keyword/value pairs may be appended :l
keyword = {tensor} :l
{tensor} value = none
:ule
[Examples:] [Examples:]
compute 1 molecule gyration/molecule :pre compute 1 molecule gyration/molecule
compute 2 molecule gyration/molecule tensor :pre
[Description:] [Description:]
@ -34,6 +39,13 @@ where M is the total mass of the molecule, Rcm is the center-of-mass
position of the molecule, and the sum is over all atoms in the position of the molecule, and the sum is over all atoms in the
molecule and in the group. molecule and in the group.
If the {tensor} keyword is specified, then the scalar Rg value is not
calculated, but an Rg tensor is instead calculated for each molecule.
The formula for the components of the tensor is the same as the above
formula, except that (Ri - Rcm)^2 is replaced by (Rix - Rcmx) * (Riy -
Rcmy) for the xy component, etc. The 6 components of the tensor are
ordered xx, yy, zz, xy, xz, yz.
Rg for a particular molecule is only computed if one or more of its Rg for a particular molecule is only computed if one or more of its
atoms are in the specified group. Normally all atoms in the molecule atoms are in the specified group. Normally all atoms in the molecule
should be in the group, however this is not required. LAMMPS will should be in the group, however this is not required. LAMMPS will
@ -57,14 +69,18 @@ image"_set.html command.
[Output info:] [Output info:]
This compute calculates a global vector of Rg values where the length This compute calculates a global vector if the {tensor} keyword is not
of the vector = Nmolecules. These values can be used by any command specified and a global array if it is. The length of the vector or
that uses global vector values from a compute as input. See "this number of rows in the array is the number of molecules. If the
{tensor} keyword is specified, the global array has 6 columns. The
vector or array can be accessed by any command that uses global values
from a compute as input. See "this
section"_Section_howto.html#howto_15 for an overview of LAMMPS output section"_Section_howto.html#howto_15 for an overview of LAMMPS output
options. options.
The vector values calculated by this compute are "intensive". The All the vector or array values calculated by this compute are
vector values will be in distance "units"_units.html. "intensive". The vector or array values will be in distance
"units"_units.html.
[Restrictions:] none [Restrictions:] none