From 190fc494b836e2a8dcd17f9a14c16c4f4cf7d8f8 Mon Sep 17 00:00:00 2001 From: pscrozi Date: Wed, 5 Dec 2012 22:55:35 +0000 Subject: [PATCH] Updating MSM documentation. git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@9143 f3b2605a-c512-4ea7-a41b-209d697bcdaa --- doc/kspace_modify.html | 13 ++++++++----- doc/kspace_modify.txt | 13 ++++++++----- doc/kspace_style.html | 7 +------ doc/kspace_style.txt | 7 +------ 4 files changed, 18 insertions(+), 22 deletions(-) diff --git a/doc/kspace_modify.html b/doc/kspace_modify.html index 6d261c2b65..d3fa736a4e 100644 --- a/doc/kspace_modify.html +++ b/doc/kspace_modify.html @@ -74,7 +74,7 @@ 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 @@ -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 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 @@ -117,14 +118,16 @@ 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 command with an absolute @@ -216,7 +219,7 @@ 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).

diff --git a/doc/kspace_modify.txt b/doc/kspace_modify.txt index 380612e2b7..158d710655 100644 --- a/doc/kspace_modify.txt +++ b/doc/kspace_modify.txt @@ -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). diff --git a/doc/kspace_style.html b/doc/kspace_style.html index 02977e6b6b..06ae1a674d 100644 --- a/doc/kspace_style.html +++ b/doc/kspace_style.html @@ -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 this section of the -manual. +manual. MSM does not currently support the -DFFT_SINGLE compiler switch.

@@ -236,11 +236,6 @@ or PPPM solver. The only exception is if the slab option is set with kspace_modify, 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, pair_style diff --git a/doc/kspace_style.txt b/doc/kspace_style.txt index d48867681e..68fc97deb2 100644 --- a/doc/kspace_style.txt +++ b/doc/kspace_style.txt @@ -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