git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@9845 f3b2605a-c512-4ea7-a41b-209d697bcdaa

doc/kspace_modify.html

@@ -173,6 +173,8 @@ volfactor. This turns off all kspace forces in the z direction.
 The <I>nozforce</I> option is not supported by MSM. For MSM, any combination
 of periodic, non-periodic, or shrink-wrapped boundaries can be set 
 using <A HREF = "boundary.html">boundary</A> (the slab approximation in not needed).
+The <I>slab</I> keyword is not currently supported by Ewald or PPPM when
+using a triclinic simulation cell.
 </P>
 <P>The <I>compute</I> keyword allows Kspace computations to be turned off,
 even though a <A HREF = "kspace_style.html">kspace_style</A> is defined.  This is
@@ -211,7 +213,9 @@ then performs analytic differentiation on the single quantity to
 generate the 3 components of the electric field at each grid point.
 This is sometimes referred to as "smoothed" PPPM.  This approach
 requires a somewhat larger PPPM mesh to achieve the same accuracy as
-the <I>ik</I> method. The <I>ad</I> method is always used for MSM.
+the <I>ik</I> method. Currently, only the <I>ik</I> method (default) can be 
+used for a triclinic simulation cell with PPPM. The <I>ad</I> method is 
+always used for MSM.
 </P>
 <P>IMPORTANT NOTE: Currently, not all PPPM styles support the <I>ad</I>
 option.  Support for those PPPM variants will be added later.

doc/kspace_modify.txt

@@ -167,6 +167,8 @@ volfactor. This turns off all kspace forces in the z direction.
 The {nozforce} option is not supported by MSM. For MSM, any combination
 of periodic, non-periodic, or shrink-wrapped boundaries can be set 
 using "boundary"_boundary.html (the slab approximation in not needed).
+The {slab} keyword is not currently supported by Ewald or PPPM when
+using a triclinic simulation cell.
 
 The {compute} keyword allows Kspace computations to be turned off,
 even though a "kspace_style"_kspace_style.html is defined.  This is
@@ -205,7 +207,9 @@ then performs analytic differentiation on the single quantity to
 generate the 3 components of the electric field at each grid point.
 This is sometimes referred to as "smoothed" PPPM.  This approach
 requires a somewhat larger PPPM mesh to achieve the same accuracy as
-the {ik} method. The {ad} method is always used for MSM.
+the {ik} method. Currently, only the {ik} method (default) can be 
+used for a triclinic simulation cell with PPPM. The {ad} method is 
+always used for MSM.
 
 IMPORTANT NOTE: Currently, not all PPPM styles support the {ad}
 option.  Support for those PPPM variants will be added later.

doc/kspace_style.html

@@ -101,10 +101,6 @@ but in a more efficient manner than the <I>ewald</I> style.  The 1/r^6
 capability means that Lennard-Jones or Buckingham potentials can be
 used without a cutoff, i.e. they become full long-range potentials.
 </P>
-<P>The <I>ewald/disp</I> style can also be used with non-orthogonal (triclinic
-symmetry) simulation boxes.  It is currently the only long-range
-solver that has this capability.
-</P>
 <HR>
 
 <P>The <I>pppm</I> style invokes a particle-particle particle-mesh solver
@@ -196,6 +192,18 @@ smaller than the reference force.
 to determine the number of K-space vectors for style <I>ewald</I> or the
 grid size for style <I>pppm</I> or <I>msm</I>. 
 </P>
+<P>Note that style <I>pppm</I> only computes the grid size at the beginning of
+a simulation, so if the length or triclinic tilt of the simulation cell
+increases dramatically during the course of the simulation, the accuracy
+of the simulation may degrade. For example, for a triclinic system with 
+all three tilt factors set to the maximum limit, the PPPM grid should be
+increased roughly by a factor of 1.5 in the y direction and 2.0 in the z
+direction as compared to the same system using a cubic orthogonal simulation
+cell. One way to ensure the accuracy requirement is being met is to run a 
+short simulation at the maximum expected tilt or length, note the required
+grid size, and then use the <A HREF = "kspace_modify.html">kspace_modify</A> <I>mesh</I> 
+command to manually set the PPPM grid size to this value.
+</P>
 <P>RMS force errors in real space for <I>ewald</I> and <I>pppm</I> are estimated
 using equation 18 of <A HREF = "#Kolafa">(Kolafa)</A>, which is also referenced as
 equation 9 of <A HREF = "#Petersen">(Petersen)</A>. RMS force errors in K-space for
@@ -242,6 +250,11 @@ more instructions on how to use the accelerated styles effectively.
 </P>
 <P><B>Restrictions:</B>
 </P>
+<P>The <I>ewald/disp</I>, <I>ewald</I>, <I>pppm</I>, and <I>msm</I> styles support 
+non-orthogonal (triclinic symmetry) simulation boxes. However, triclinic
+simulation cells may not yet be supported by suffix versions of these 
+styles (such as <I>pppm/cuda</I>). 
+</P>
 <P>All of the kspace styles are part of the KSPACE package.  They are
 only enabled if LAMMPS was built with that package.  See the <A HREF = "Section_start.html#start_3">Making
 LAMMPS</A> section for more info.  Note that

doc/kspace_style.txt

@@ -94,10 +94,6 @@ but in a more efficient manner than the {ewald} style.  The 1/r^6
 capability means that Lennard-Jones or Buckingham potentials can be
 used without a cutoff, i.e. they become full long-range potentials.
 
-The {ewald/disp} style can also be used with non-orthogonal (triclinic
-symmetry) simulation boxes.  It is currently the only long-range
-solver that has this capability.
-
 :line
 
 The {pppm} style invokes a particle-particle particle-mesh solver
@@ -189,6 +185,18 @@ The accuracy setting is used in conjunction with the pairwise cutoff
 to determine the number of K-space vectors for style {ewald} or the
 grid size for style {pppm} or {msm}. 
 
+Note that style {pppm} only computes the grid size at the beginning of
+a simulation, so if the length or triclinic tilt of the simulation cell
+increases dramatically during the course of the simulation, the accuracy
+of the simulation may degrade. For example, for a triclinic system with 
+all three tilt factors set to the maximum limit, the PPPM grid should be
+increased roughly by a factor of 1.5 in the y direction and 2.0 in the z
+direction as compared to the same system using a cubic orthogonal simulation
+cell. One way to ensure the accuracy requirement is being met is to run a 
+short simulation at the maximum expected tilt or length, note the required
+grid size, and then use the "kspace_modify"_kspace_modify.html {mesh} 
+command to manually set the PPPM grid size to this value.
+
 RMS force errors in real space for {ewald} and {pppm} are estimated
 using equation 18 of "(Kolafa)"_#Kolafa, which is also referenced as
 equation 9 of "(Petersen)"_#Petersen. RMS force errors in K-space for
@@ -235,6 +243,11 @@ more instructions on how to use the accelerated styles effectively.
 
 [Restrictions:]
 
+The {ewald/disp}, {ewald}, {pppm}, and {msm} styles support 
+non-orthogonal (triclinic symmetry) simulation boxes. However, triclinic
+simulation cells may not yet be supported by suffix versions of these 
+styles (such as {pppm/cuda}). 
+
 All of the kspace styles are part of the KSPACE package.  They are
 only enabled if LAMMPS was built with that package.  See the "Making
 LAMMPS"_Section_start.html#start_3 section for more info.  Note that