--- manual/s_phys_pkgs/text/exch2.tex	2004/03/19 21:25:45	1.17
+++ manual/s_phys_pkgs/text/exch2.tex	2004/05/06 15:21:01	1.18
@@ -1,4 +1,4 @@
-% $Header: /home/ubuntu/mnt/e9_copy/manual/s_phys_pkgs/text/exch2.tex,v 1.17 2004/03/19 21:25:45 afe Exp $
+% $Header: /home/ubuntu/mnt/e9_copy/manual/s_phys_pkgs/text/exch2.tex,v 1.18 2004/05/06 15:21:01 afe Exp $
 % $Name:  $
 
 %%  * Introduction
@@ -32,7 +32,7 @@
 validity of the cube topology depends on the \file{SIZE.h} file as
 detailed below.  The default files provided in the release configure a
 cubed sphere topology of six tiles, one per subdomain, each with
-32$\times$32 grid points, all running on a single processor.  Both
+32$\times$32 grid points, with all tiles running on a single processor.  Both
 files are generated by Matlab scripts in
 \file{utils/exch2/matlab-topology-generator}; see Section
 \ref{sec:topogen} \sectiontitle{Generating Topology Files for exch2}
@@ -66,8 +66,8 @@
   \file{tile00$n$.mitgrid} where $n$=\code{(1:6)} (one per subdomain),
   must be in the working directory when the MITgcm executable is run.
   These files are provided in the example experiments for cubed sphere
-  configurations with 32$\times$32 cube sides and are non-trivial to
-  generate -- please contact MITgcm support if you want to generate
+  configurations with 32$\times$32 cube sides 
+  -- please contact MITgcm support if you want to generate
   files for other configurations. \\
 
 $\bullet$ As always when compiling MITgcm, the file \file{SIZE.h} must
@@ -106,7 +106,8 @@
 from the Matlab prompt (there are no parameters to pass) generates
 exch2 topology files \file{W2\_EXCH2\_TOPOLOGY.h} and
 \file{w2\_e2setup.F} in the working directory and displays a figure of
-the topology via Matlab.  The other m-files in the directory are
+the topology via Matlab -- figures \ref{fig:6tile}, \ref{fig:12tile}, 
+and \ref{fig:24tile} are examples.  The other m-files in the directory are
 subroutines of \file{driver.m} and should not be run ``bare'' except
 for development purposes. \\
 
@@ -117,13 +118,13 @@
 The first three determine the size of the subdomains and
 hence the size of the overall domain.  Each one determines the number
 of grid points, and therefore the resolution, along the subdomain
-sides in a ``great circle'' around an axis of the cube.  At the time
+sides in a ``great circle'' around each the three spatial axes of the cube.  At the time
 of this writing MITgcm requires these three parameters to be equal,
 but they provide for future releases  to accomodate different
 resolutions around the axes to allow (for example) greater resolution
 around the equator.\\
 
-The parameters \code{tnx} and \code{tny} determine the dimensions of
+The parameters \code{tnx} and \code{tny} determine the width and height of
 the tiles into which the subdomains are decomposed, and must evenly
 divide the integer assigned to \code{nr}, \code{nb} and \code{ng}.
 The result is a rectangular tiling of the subdomain.  Figure
@@ -139,8 +140,10 @@
 
 \caption{Plot of a cubed sphere topology with a 32$\times$192 domain
 divided into six 32$\times$32 subdomains, each of which is divided
-into four tiles (\code{tnx=16, tny=16}) for a total of twenty-four
-tiles.  } \label{fig:24tile}
+into four tiles of width \code{tnx=16} and height \code{tny=16} for a 
+total of twenty-four tiles.  The colored borders of the subdomains 
+represent the parameters \code{nr} (red), \code{nb} (blue), and 
+\code{ng} (green).  } \label{fig:24tile}
 \end{figure}
 
 \begin{figure}
@@ -287,8 +290,8 @@
 tile layout to allow global data files that are tile-layout-neutral
 and have no bearing on the internal storage of the arrays.  The tiles
 are stored internally in a range from \code{(1:\varlink{bi}{bi})} the
-$x$ axis, and the $y$ axis variable \varlink{bj}{bj} generally is
-ignored within the package. \\
+$x$ axis, and the $y$ axis variable \varlink{bj}{bj} is assumed to 
+equal \code{1} throughout the package. \\
 
 \subsubsection{Arrays Indexed to Tile Number}
 
@@ -301,7 +304,7 @@
 each tile.  At present for each tile \texttt{exch2\_tnx=sNx} and
 \texttt{exch2\_tny=sNy}, as assigned in \file{SIZE.h} and described in
 section \ref{sec:exch2mpi} \sectiontitle{exch2, SIZE.h, and
-multiprocessing}.  Future releases of MITgcm are to allow varying tile
+multiprocessing}.  Future releases of MITgcm may allow varying tile
 sizes. \\
 
 The location of the tiles' Cartesian origin within a subdomain are
