git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@5017 f3b2605a-c512-4ea7-a41b-209d697bcdaa

This commit is contained in:
sjplimp 2010-10-11 16:45:51 +00:00
parent 422c7453a1
commit 50fb5e430b
6 changed files with 120 additions and 36 deletions

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@ -137,17 +137,50 @@ LAMMPS <A HREF = "Section_tools.html">post-processing tools</A>, including
this format.
</P>
<P>For post-processing purposes the <I>atom</I> and <I>custom</I> text files are
self-describing in the following sense. The simulation box bounds are
included in each snapshot and if the box is triclinic
(non-orthogonal), then the tilt factors are also printed; see the
<A HREF = "region.html">region prism</A> command for a description of tilt factors.
For triclinic boxes the box bounds themselves (first 2 quantities on
each line) are a true "bounding box" around the simulation domain,
which means they include the effect of any tilt. The "ITEM: ATOMS"
line in each snapshot also lists the meaning of each column of the
per-atom lines that follow. For example, this would be "id type xs ys
zs" for the default <I>atom</I> style, and it will be the atom attributes
you specify in the dump command for the <I>custom</I> style.
self-describing in the following sense.
</P>
<P>The simulation box bounds are included in each snapshot. For
orthogonal boxes this is formatted as:
</P>
<PRE>ITEM: BOX BOUNDS
xlo xhi
ylo yhi
zlo zhi
</PRE>
<P>where xlo,xhi are the bounds of the simulation box in the x-dimension,
and similarly for y and z.
</P>
<P>For triclinic boxes (non-orthogonal), the tilt factors are also
included, as a 3rd value on each line:
</P>
<PRE>ITEM: BOX BOUNDS xy xz yz
xlo_bound xhi_bound xy
ylo_bound yhi_bound xz
zlo_bound zhi_bound yz
</PRE>
<P>See the <A HREF = "region.html">region prism</A> or <A HREF = "read_data.html">read_data</A>
commands for a description of tilt factors in LAMMPS, and their
relationship to other nomenclatures for triclinic geometries,
e.g. using 3 lattice constants <I>a</I>, <I>b</I>, and <I>c</I>, and 3 angles
<I>alpha</I>, <I>beta</I> and <I>gamma</I>.
</P>
<P>IMPORTANT NOTE: As noted above, for triclinic simulation boxes, the 6
box bounds (xlo,xhi,ylo,yhi,zlo,zhi) are actually written to the dump
file as a "bounding box" around the simulation domain, which means
they include the effect of any tilt, which is convenient for many
visualization programs. The bounding box is calculated as follows:
</P>
<PRE>xlo_bound = MIN(xlo,xlo+xy,xlo+xz,xlo+xy+xz)
xhi_bound = MAX(xhi,xhi+xy,xhi+xz,xhi+xy+xz)
ylo_bound = MIN(ylo,ylo+yz)
yhi_bound = MAX(yhi,yhi+yz)
zlo_bound = zlo
zhi_bound = zhi
</PRE>
<P>The "ITEM: ATOMS" line in each snapshot lists column descriptors for
the per-atom lines that follow. For example, the descriptors would be
"id type xs ys zs" for the default <I>atom</I> style, and would be the atom
attributes you specify in the dump command for the <I>custom</I> style.
</P>
<P>For style <I>atom</I>, atom coordinates are written to the file, along with
the atom ID and atom type. By default, atom coords are written in a

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@ -127,17 +127,50 @@ LAMMPS "post-processing tools"_Section_tools.html, including
this format.
For post-processing purposes the {atom} and {custom} text files are
self-describing in the following sense. The simulation box bounds are
included in each snapshot and if the box is triclinic
(non-orthogonal), then the tilt factors are also printed; see the
"region prism"_region.html command for a description of tilt factors.
For triclinic boxes the box bounds themselves (first 2 quantities on
each line) are a true "bounding box" around the simulation domain,
which means they include the effect of any tilt. The "ITEM: ATOMS"
line in each snapshot also lists the meaning of each column of the
per-atom lines that follow. For example, this would be "id type xs ys
zs" for the default {atom} style, and it will be the atom attributes
you specify in the dump command for the {custom} style.
self-describing in the following sense.
The simulation box bounds are included in each snapshot. For
orthogonal boxes this is formatted as:
ITEM: BOX BOUNDS
xlo xhi
ylo yhi
zlo zhi :pre
where xlo,xhi are the bounds of the simulation box in the x-dimension,
and similarly for y and z.
For triclinic boxes (non-orthogonal), the tilt factors are also
included, as a 3rd value on each line:
ITEM: BOX BOUNDS xy xz yz
xlo_bound xhi_bound xy
ylo_bound yhi_bound xz
zlo_bound zhi_bound yz :pre
See the "region prism"_region.html or "read_data"_read_data.html
commands for a description of tilt factors in LAMMPS, and their
relationship to other nomenclatures for triclinic geometries,
e.g. using 3 lattice constants {a}, {b}, and {c}, and 3 angles
{alpha}, {beta} and {gamma}.
IMPORTANT NOTE: As noted above, for triclinic simulation boxes, the 6
box bounds (xlo,xhi,ylo,yhi,zlo,zhi) are actually written to the dump
file as a "bounding box" around the simulation domain, which means
they include the effect of any tilt, which is convenient for many
visualization programs. The bounding box is calculated as follows:
xlo_bound = MIN(xlo,xlo+xy,xlo+xz,xlo+xy+xz)
xhi_bound = MAX(xhi,xhi+xy,xhi+xz,xhi+xy+xz)
ylo_bound = MIN(ylo,ylo+yz)
yhi_bound = MAX(yhi,yhi+yz)
zlo_bound = zlo
zhi_bound = zhi :pre
The "ITEM: ATOMS" line in each snapshot lists column descriptors for
the per-atom lines that follow. For example, the descriptors would be
"id type xs ys zs" for the default {atom} style, and would be the atom
attributes you specify in the dump command for the {custom} style.
For style {atom}, atom coordinates are written to the file, along with
the atom ID and atom type. By default, atom coords are written in a

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@ -109,8 +109,8 @@ since if the maximum tilt factor is 5 (as in this example), then
configurations with tilt = ..., -15, -5, 5, 15, 25, ... are all
equivalent.
</P>
<P>Many crystal structures are defined using three lattice constants <I>a</I>,
<I>b</I>, and <I>c</I>, and three angles <I>alpha</I>, <I>beta</I> and <I>gamma</I>. The
<P>Crystal structures are often defined using three lattice constants
<I>a</I>, <I>b</I>, and <I>c</I>, and three angles <I>alpha</I>, <I>beta</I> and <I>gamma</I>. The
relationships between these quantities and the LAMMPS box dimensions
(lx,ly,lz) = (xhi-xlo,yhi-ylo,zhi-zlo) and tilt factors (xy,xz,yz) are
as follows:

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@ -106,8 +106,8 @@ since if the maximum tilt factor is 5 (as in this example), then
configurations with tilt = ..., -15, -5, 5, 15, 25, ... are all
equivalent.
Many crystal structures are defined using three lattice constants {a},
{b}, and {c}, and three angles {alpha}, {beta} and {gamma}. The
Crystal structures are often defined using three lattice constants
{a}, {b}, and {c}, and three angles {alpha}, {beta} and {gamma}. The
relationships between these quantities and the LAMMPS box dimensions
(lx,ly,lz) = (xhi-xlo,yhi-ylo,zhi-zlo) and tilt factors (xy,xz,yz) are
as follows:

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@ -85,11 +85,13 @@ region 2 sphere 0.0 0.0 0.0 5 side out wiggle 1 1 0 10
</P>
<P>This command defines a geometric region of space. Various other
commands use regions. For example, the region can be filled with
atoms via the <A HREF = "create_atoms.html">create_atoms</A> command. Or the atoms
in the region can be identified as a group via the <A HREF = "group.html">group</A>
command, or deleted via the <A HREF = "delete_atoms.html">delete_atoms</A> command.
Or the surface of the region can be used as a boundary wall via the
<A HREF = "fix_wall_region.html">fix wall/region</A> command.
atoms via the <A HREF = "create_atoms.html">create_atoms</A> command. Or a bounding
box around the region, can be used to define the simulation box via
the <A HREF = "create_box.html">create_box</A> command. Or the atoms in the region
can be identified as a group via the <A HREF = "group.html">group</A> command, or
deleted via the <A HREF = "delete_atoms.html">delete_atoms</A> command. Or the
surface of the region can be used as a boundary wall via the <A HREF = "fix_wall_region.html">fix
wall/region</A> command.
</P>
<P>Normally, regions in LAMMPS are "static", meaning their geometric
extent does not change with time. If the <I>vel</I> or <I>wiggle</I> or
@ -162,6 +164,13 @@ results in a parallelepiped whose "origin" is at (xlo,ylo,zlo) with 3
edge vectors starting from its origin given by a = (xhi-xlo,0,0); b =
(xy,yhi-ylo,0); c = (xz,yz,zhi-zlo).
</P>
<P>Crystal structures are often defined using three lattice constants
<I>a</I>, <I>b</I>, and <I>c</I>, and three angles <I>alpha</I>, <I>beta</I> and <I>gamma</I>. The
relationships between these quantities and a prism with (lx,ly,lz) =
(xhi-xlo,yhi-ylo,zhi-zlo) and tilt factors (xy,xz,yz) are as follows:
</P>
<CENTER><IMG SRC = "Eqs/box.jpg">
</CENTER>
<P>A prism region used with the <A HREF = "create_box.html">create_box</A> command must
have tilt factors (xy,xz,yz) that do not skew the box more than half
the distance of the parallel box length. For example, if xlo = 2 and

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@ -76,11 +76,13 @@ region 2 sphere 0.0 0.0 0.0 5 side out wiggle 1 1 0 10 :pre
This command defines a geometric region of space. Various other
commands use regions. For example, the region can be filled with
atoms via the "create_atoms"_create_atoms.html command. Or the atoms
in the region can be identified as a group via the "group"_group.html
command, or deleted via the "delete_atoms"_delete_atoms.html command.
Or the surface of the region can be used as a boundary wall via the
"fix wall/region"_fix_wall_region.html command.
atoms via the "create_atoms"_create_atoms.html command. Or a bounding
box around the region, can be used to define the simulation box via
the "create_box"_create_box.html command. Or the atoms in the region
can be identified as a group via the "group"_group.html command, or
deleted via the "delete_atoms"_delete_atoms.html command. Or the
surface of the region can be used as a boundary wall via the "fix
wall/region"_fix_wall_region.html command.
Normally, regions in LAMMPS are "static", meaning their geometric
extent does not change with time. If the {vel} or {wiggle} or
@ -153,6 +155,13 @@ results in a parallelepiped whose "origin" is at (xlo,ylo,zlo) with 3
edge vectors starting from its origin given by a = (xhi-xlo,0,0); b =
(xy,yhi-ylo,0); c = (xz,yz,zhi-zlo).
Crystal structures are often defined using three lattice constants
{a}, {b}, and {c}, and three angles {alpha}, {beta} and {gamma}. The
relationships between these quantities and a prism with (lx,ly,lz) =
(xhi-xlo,yhi-ylo,zhi-zlo) and tilt factors (xy,xz,yz) are as follows:
:c,image(Eqs/box.jpg)
A prism region used with the "create_box"_create_box.html command must
have tilt factors (xy,xz,yz) that do not skew the box more than half
the distance of the parallel box length. For example, if xlo = 2 and