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Updating MSM documentation. 

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@9143 f3b2605a-c512-4ea7-a41b-209d697bcdaa
This commit is contained in:
pscrozi 2012-12-05 22:55:35 +00:00
parent 05db562cb2
commit 190fc494b8
4 changed files with 18 additions and 22 deletions
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13
doc/kspace_modify.html
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@ -74,7 +74,7 @@ Values for x,y,z of 0,0,0 unset the option.
</P>
<P>The <I>order</I> keyword determines how many grid spacings an atom's charge
extends when it is mapped to the grid in kspace style <I>pppm</I> or <I>msm</I>.
The default for this parameter is 5 for PPPM and 4 for MSM, which
The default for this parameter is 5 for PPPM and 8 for MSM, which
means each charge spans 5 or 4 grid cells in each dimension,
respectively. For the LAMMPS implementation of MSM, the order can
range from 4 to 10 and must be even. For PPPM, the minimum allowed
@ -103,7 +103,8 @@ allowed to extend beyond nearest-neighbor processors, e.g. when using
lots of processors on a small problem. If it is set to <I>no</I> then the
communication will be limited to nearest-neighbor processors and the
<I>order</I> setting will be reduced if necessary, as explained by the
<I>minorder</I> keyword discussion. The same is also true for MSM.
<I>minorder</I> keyword discussion. The <I>overlap</I> keyword is always set to
<I>yes</I> in MSM.
</P>
<P>The <I>minorder</I> keyword allows LAMMPS to reduce the <I>order</I> setting if
necessary to keep the communication of ghost grid point limited to
@ -117,14 +118,16 @@ neighbor processors. The <I>minorder</I> keyword limits how small the
which is the default. If <I>minorder</I> is set to the same value as
<I>order</I> then no reduction is allowed, and LAMMPS will generate an
error if the grid communcation is non-nearest-neighbor and <I>overlap</I>
is set to <I>no</I>.
is set to <I>no</I>. The <I>minorder</I> keyword is not currently supported in
MSM.
</P>
<P>The PPPM order parameter may be reset by LAMMPS when it sets up the
FFT grid if the implied grid stencil extends beyond the grid cells
owned by neighboring processors. Typically this will only occur when
small problems are run on large numbers of processors. A warning will
be generated indicating the order parameter is being reduced to allow
LAMMPS to run the problem. The same setup is also implemented in MSM.
LAMMPS to run the problem. Automatic adjustment of the order parameter
is not supported in MSM.
</P>
<P>The <I>force</I> keyword overrides the relative accuracy parameter set by
the <A HREF = "kspace_style.html">kspace_style</A> command with an absolute
@ -216,7 +219,7 @@ option. Support for those PPPM variants will be added later.
<P><B>Default:</B>
</P>
<P>The option defaults are mesh = mesh/disp = 0 0 0, order = order/disp =
5 (PPPM), order = 4 (MSM), minorder = 2, overlap = yes, force = -1.0,
5 (PPPM), order = 8 (MSM), minorder = 2, overlap = yes, force = -1.0,
gewald = gewald/disp = 0.0, slab = 1.0, compute = yes, cutoff/adjust =
yes, and diff = ik (PPPM), diff = ad (MSM).
</P>

13
doc/kspace_modify.txt
View File

@ -68,7 +68,7 @@ Values for x,y,z of 0,0,0 unset the option.
The {order} keyword determines how many grid spacings an atom's charge
extends when it is mapped to the grid in kspace style {pppm} or {msm}.
The default for this parameter is 5 for PPPM and 4 for MSM, which
The default for this parameter is 5 for PPPM and 8 for MSM, which
means each charge spans 5 or 4 grid cells in each dimension,
respectively. For the LAMMPS implementation of MSM, the order can
range from 4 to 10 and must be even. For PPPM, the minimum allowed
@ -97,7 +97,8 @@ allowed to extend beyond nearest-neighbor processors, e.g. when using
lots of processors on a small problem. If it is set to {no} then the
communication will be limited to nearest-neighbor processors and the
{order} setting will be reduced if necessary, as explained by the
{minorder} keyword discussion. The same is also true for MSM.
{minorder} keyword discussion. The {overlap} keyword is always set to
{yes} in MSM.
The {minorder} keyword allows LAMMPS to reduce the {order} setting if
necessary to keep the communication of ghost grid point limited to
@ -111,14 +112,16 @@ neighbor processors. The {minorder} keyword limits how small the
which is the default. If {minorder} is set to the same value as
{order} then no reduction is allowed, and LAMMPS will generate an
error if the grid communcation is non-nearest-neighbor and {overlap}
is set to {no}.
is set to {no}. The {minorder} keyword is not currently supported in
MSM.
The PPPM order parameter may be reset by LAMMPS when it sets up the
FFT grid if the implied grid stencil extends beyond the grid cells
owned by neighboring processors. Typically this will only occur when
small problems are run on large numbers of processors. A warning will
be generated indicating the order parameter is being reduced to allow
LAMMPS to run the problem. The same setup is also implemented in MSM.
LAMMPS to run the problem. Automatic adjustment of the order parameter
is not supported in MSM.
The {force} keyword overrides the relative accuracy parameter set by
the "kspace_style"_kspace_style.html command with an absolute
@ -210,7 +213,7 @@ option. Support for those PPPM variants will be added later.
[Default:]
The option defaults are mesh = mesh/disp = 0 0 0, order = order/disp =
5 (PPPM), order = 4 (MSM), minorder = 2, overlap = yes, force = -1.0,
5 (PPPM), order = 8 (MSM), minorder = 2, overlap = yes, force = -1.0,
gewald = gewald/disp = 0.0, slab = 1.0, compute = yes, cutoff/adjust =
yes, and diff = ik (PPPM), diff = ad (MSM).

7
doc/kspace_style.html
View File

@ -149,7 +149,7 @@ interpolating electric fields to particles) to be performed in single
precision. This option can speed-up long-range calulations,
particularly in parallel or on GPUs. The use of the -DFFT_SINGLE flag
is discussed in <A HREF = "Section_start.html#start_2_4">this section</A> of the
manual.
manual. MSM does not currently support the -DFFT_SINGLE compiler switch.
</P>
<HR>
@ -236,11 +236,6 @@ or PPPM solver. The only exception is if the slab option is set with
<A HREF = "kspace_modify.html">kspace_modify</A>, in which case the xy dimensions
must be periodic and the z dimension must be non-periodic.
</P>
<P>The <I>msm</I> style is fairly new, and still lacks some important features
and optimizations. The upper MSM levels (above the first level) are not
parallelized, so this MSM implementation may not yet scale very well
on large core counts.
</P>
<P><B>Related commands:</B>
</P>
<P><A HREF = "kspace_modify.html">kspace_modify</A>, <A HREF = "pair_lj.html">pair_style

7
doc/kspace_style.txt
View File

@ -142,7 +142,7 @@ interpolating electric fields to particles) to be performed in single
precision. This option can speed-up long-range calulations,
particularly in parallel or on GPUs. The use of the -DFFT_SINGLE flag
is discussed in "this section"_Section_start.html#start_2_4 of the
manual.
manual. MSM does not currently support the -DFFT_SINGLE compiler switch.
:line
@ -229,11 +229,6 @@ or PPPM solver. The only exception is if the slab option is set with
"kspace_modify"_kspace_modify.html, in which case the xy dimensions
must be periodic and the z dimension must be non-periodic.
The {msm} style is fairly new, and still lacks some important features
and optimizations. The upper MSM levels (above the first level) are not
parallelized, so this MSM implementation may not yet scale very well
on large core counts.
[Related commands:]
"kspace_modify"_kspace_modify.html, "pair_style