Information and diagrams for computational grid partitioning, pointing out that irregular partitions are not possible

git-svn-id: http://svn.cactuscode.org/arrangements/CactusPUGH/PUGH/trunk@370 b61c5cb5-eaca-4651-9a7a-d64986f99364

1 files changed, 28 insertions, 10 deletions

diff --git a/doc/documentation.tex b/doc/documentation.tex
index 73982d0..47d7926 100644
--- a/doc/documentation.tex
+++ b/doc/documentation.tex
@@ -147,16 +147,34 @@ driver::periodic_z = "no"
 \section{Load Balancing}
 
 By default PUGH will distribute the computational grid evenly across
-all processors. This may not be efficient if there is a different
-computational load on different processors, or for example for a simulation
-distributed across different processor speeds. 
-
-The computational grid can be manually distributed using the parameters
-{\tt partition[\_1d\_x|\_2d\_x|\_2d\_y|\_3d\_x|\_3d\_y|\_3d\_z]}. To manual specify the 
-load distribution, set {\tt pugh::partition = ``manual''} and then, 
-depending on the grid dimension, set the remaining parameters 
-to distribute the load in each direction. Note that for this you need
-to know apriori the processor decomposition. 
+all processors (as in Figure~\ref{pugh::fig2}a). This may not be
+efficient if there is a different computational load on different
+processors, or for example for a simulation distributed across
+different processor speeds.
+
+\begin{figure}[ht]
+\begin{center}
+\ifpdf
+\else
+\includegraphics[angle=0,width=12cm]{Partitioning.eps}
+\fi
+\end{center}
+\caption[]{Partitioning of the computational grid across processors, Figure~a) is the default type of partition used by {\tt PUGH}, Figure~b) can be set
+manually, and Figure~c) is not possible with {\tt PUGH}} 
+\label{pugh::fig2}
+\end{figure}
+
+The computational grid can be manually partitioned in a regularly way 
+as in Figure~\ref{pugh::fig2}b. (Note that the type of partitioning 
+shown in Figure~\ref{pugh::fig2}c is not possible with {\tt PUGH}).
+
+The computational grid can be manually distributed using the
+parameters {\tt
+partition[\_1d\_x|\_2d\_x|\_2d\_y|\_3d\_x|\_3d\_y|\_3d\_z]}. To manual
+specify the load distribution, set {\tt pugh::partition = ``manual''}
+and then, depending on the grid dimension, set the remaining
+parameters to distribute the load in each direction. Note that for
+this you need to know apriori the processor decomposition.
 
 The decomposition is easiest to explain with an example,
 to distribute a grid with $30 \times 30$ points across