Updating kspace docs to reflect changes in MSM allowing non-periodic boundaries.
git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@9244 f3b2605a-c512-4ea7-a41b-209d697bcdaa
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pscrozi
@ -168,8 +168,10 @@ must prevent particle migration beyond the initial z-bounds, typically
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by providing a wall-style fix. The methodology behind the <I>slab</I>
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option is explained in the paper by <A HREF = "#Yeh">(Yeh)</A>. An alternative slab
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option can be invoked with the <I>nozforce</I> keyword in lieu of the
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volfactor. This turns off all kspace forces in the z direction. The
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<I>slab</I> and <I>nozforce</I> options are not allowed for MSM.
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volfactor. This turns off all kspace forces in the z direction.
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The <I>nozforce</I> option is not supported by MSM. For MSM, any combination
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of periodic, non-periodic, or shrink-wrapped boundaries can be set
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using <A HREF = "boundary.html">boundary</A> (the slab approximation in not needed).
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</P>
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<P>The <I>compute</I> keyword allows Kspace computations to be turned off,
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even though a <A HREF = "kspace_style.html">kspace_style</A> is defined. This is
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@ -203,9 +205,7 @@ then performs analytic differentiation on the single quantity to
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generate the 3 components of the electric field at each grid point.
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This is sometimes referred to as "smoothed" PPPM. This approach
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requires a somewhat larger PPPM mesh to achieve the same accuracy as
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the <I>ik</I> method. Analogous approaches have been implemented in MSM
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and can be specified using the same keywords. The <I>ad</I> approach is
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the default for MSM.
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the <I>ik</I> method. The <I>ad</I> method is always used for MSM.
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</P>
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<P>IMPORTANT NOTE: Currently, not all PPPM styles support the <I>ad</I>
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option. Support for those PPPM variants will be added later.
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@ -221,7 +221,7 @@ option. Support for those PPPM variants will be added later.
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<P>The option defaults are mesh = mesh/disp = 0 0 0, order = order/disp =
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5 (PPPM), order = 8 (MSM), minorder = 2, overlap = yes, force = -1.0,
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gewald = gewald/disp = 0.0, slab = 1.0, compute = yes, cutoff/adjust =
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yes, and diff = ik (PPPM), diff = ad (MSM).
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yes (MSM), and diff = ik (PPPM).
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</P>
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<HR>
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@ -162,8 +162,10 @@ must prevent particle migration beyond the initial z-bounds, typically
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by providing a wall-style fix. The methodology behind the {slab}
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option is explained in the paper by "(Yeh)"_#Yeh. An alternative slab
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option can be invoked with the {nozforce} keyword in lieu of the
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volfactor. This turns off all kspace forces in the z direction. The
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{slab} and {nozforce} options are not allowed for MSM.
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volfactor. This turns off all kspace forces in the z direction.
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The {nozforce} option is not supported by MSM. For MSM, any combination
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of periodic, non-periodic, or shrink-wrapped boundaries can be set
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using "boundary"_boundary.html (the slab approximation in not needed).
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The {compute} keyword allows Kspace computations to be turned off,
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even though a "kspace_style"_kspace_style.html is defined. This is
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@ -197,9 +199,7 @@ then performs analytic differentiation on the single quantity to
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generate the 3 components of the electric field at each grid point.
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This is sometimes referred to as "smoothed" PPPM. This approach
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requires a somewhat larger PPPM mesh to achieve the same accuracy as
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the {ik} method. Analogous approaches have been implemented in MSM
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and can be specified using the same keywords. The {ad} approach is
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the default for MSM.
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the {ik} method. The {ad} method is always used for MSM.
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IMPORTANT NOTE: Currently, not all PPPM styles support the {ad}
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option. Support for those PPPM variants will be added later.
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@ -215,7 +215,7 @@ option. Support for those PPPM variants will be added later.
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The option defaults are mesh = mesh/disp = 0 0 0, order = order/disp =
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5 (PPPM), order = 8 (MSM), minorder = 2, overlap = yes, force = -1.0,
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gewald = gewald/disp = 0.0, slab = 1.0, compute = yes, cutoff/adjust =
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yes, and diff = ik (PPPM), diff = ad (MSM).
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yes (MSM), and diff = ik (PPPM).
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:line
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@ -73,7 +73,7 @@ style</A> to perform consistent short-range pairwise
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calculations. This means that the name of the pair style contains a
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matching keyword to the name of the KSpace style, as in this table:
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</P>
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<DIV ALIGN=center><TABLE BORDER=1 >
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<DIV ALIGN=center><TABLE WIDTH="0%" BORDER=1 >
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<TR ALIGN="center"><TD >Pair style </TD><TD > KSpace style </TD></TR>
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<TR ALIGN="center"><TD >coul/long </TD><TD > ewald or pppm</TD></TR>
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<TR ALIGN="center"><TD >coul/msm </TD><TD > msm</TD></TR>
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@ -159,7 +159,8 @@ mesh, and uses a multi-level hierarchy of coarser and coarser meshes
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on which direct coulomb solves are done. This method does not use
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FFTs and scales as N. It may therefore be faster than the other
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K-space solvers for relatively large problems when running on large
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core counts.
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core counts. MSM can also be used for non-periodic boundary conditions and
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for mixed periodic and non-periodic boundaries.
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</P>
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<P>MSM is most competitive versus Ewald and PPPM when only relatively
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low accuracy forces, about 1e-4 relative error or less accurate,
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@ -167,6 +168,10 @@ are needed. Note that use of a larger coulomb cutoff (i.e. 15
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angstroms instead of 10 angstroms) provides better MSM accuracy for
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both the real space and grid computed forces.
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</P>
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<P>Currently the pressure calculation in MSM is expensive,
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so calculating the pressure at every timestep or using a fixed pressure
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simulation with MSM will cause the code to run slower.
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</P>
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<HR>
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<P>The specified <I>accuracy</I> determines the relative RMS error in per-atom
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@ -231,10 +236,14 @@ only enabled if LAMMPS was built with that package. See the <A HREF = "Section_
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LAMMPS</A> section for more info. Note that
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the KSPACE package is installed by default.
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</P>
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<P>A simulation must be 3d and periodic in all dimensions to use an Ewald
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or PPPM solver. The only exception is if the slab option is set with
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<A HREF = "kspace_modify.html">kspace_modify</A>, in which case the xy dimensions
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must be periodic and the z dimension must be non-periodic.
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<P>For MSM, a simulation must be 3d and one can use any combination of
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periodic, non-periodic, or shrink-wrapped boundaries (specified using
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the <A HREF = "boundary.html">boundary</A> command).
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</P>
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<P>For Ewald and PPPM, a simulation must be 3d and periodic in all dimensions.
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The only exception is if the slab option is set with <A HREF = "kspace_modify.html">kspace_modify</A>,
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in which case the xy dimensions must be periodic and the z dimension must be
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non-periodic.
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</P>
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<P><B>Related commands:</B>
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</P>
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@ -152,7 +152,8 @@ mesh, and uses a multi-level hierarchy of coarser and coarser meshes
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on which direct coulomb solves are done. This method does not use
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FFTs and scales as N. It may therefore be faster than the other
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K-space solvers for relatively large problems when running on large
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core counts.
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core counts. MSM can also be used for non-periodic boundary conditions and
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for mixed periodic and non-periodic boundaries.
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MSM is most competitive versus Ewald and PPPM when only relatively
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low accuracy forces, about 1e-4 relative error or less accurate,
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@ -160,6 +161,10 @@ are needed. Note that use of a larger coulomb cutoff (i.e. 15
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angstroms instead of 10 angstroms) provides better MSM accuracy for
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both the real space and grid computed forces.
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Currently the pressure calculation in MSM is expensive,
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so calculating the pressure at every timestep or using a fixed pressure
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simulation with MSM will cause the code to run slower.
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:line
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The specified {accuracy} determines the relative RMS error in per-atom
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@ -224,10 +229,14 @@ only enabled if LAMMPS was built with that package. See the "Making
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LAMMPS"_Section_start.html#start_3 section for more info. Note that
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the KSPACE package is installed by default.
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A simulation must be 3d and periodic in all dimensions to use an Ewald
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or PPPM solver. The only exception is if the slab option is set with
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"kspace_modify"_kspace_modify.html, in which case the xy dimensions
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must be periodic and the z dimension must be non-periodic.
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For MSM, a simulation must be 3d and one can use any combination of
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periodic, non-periodic, or shrink-wrapped boundaries (specified using
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the "boundary"_boundary.html command).
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For Ewald and PPPM, a simulation must be 3d and periodic in all dimensions.
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The only exception is if the slab option is set with "kspace_modify"_kspace_modify.html,
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in which case the xy dimensions must be periodic and the z dimension must be
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non-periodic.
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[Related commands:]
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