Change set|get_large_threshold into hash_threshold

docs/src/datastruct.tex

@@ -387,11 +387,11 @@ accelerators.
 
 
 
-\subsubsection{psb\_cd\_get\_large\_threshold --- Get threshold for
+\subsubsection{psb\_cd\_get\_hash\_threshold --- Get threshold for
   index mapping switch}
 
 \begin{verbatim}
-ith = psb_cd_get_large_threshold()
+ith = psb_cd_get_hash_threshold()
 \end{verbatim}
 
 \begin{description}
@@ -403,12 +403,12 @@ ith = psb_cd_get_large_threshold()
 
 
 
-\subsubsection{psb\_cd\_set\_large\_threshold --- Set threshold for
+\subsubsection{psb\_cd\_set\_hash\_threshold --- Set threshold for
   index mapping switch}
 %\addcontentsline{toc}{paragraph}{psb\_cd\_set\_large\_threshold}
 
 \begin{verbatim}
-call psb_cd_set_large_threshold(ith)
+call psb_cd_set_hash_threshold(ith)
 \end{verbatim}
 
 \begin{description}
@@ -420,6 +420,11 @@ Type: {\bf required}.\\
 Intent: {\bf in}.\\
 Specified as: an integer value greater than zero.
 \end{description}
+This threshold guides the library into using a list based or a
+hash-table based descriptor for global to local index conversion;
+if the size of the global index space is below this threshold, a list
+based structure is used, if it is above a hash-table based structure
+is used. 
 Note: the threshold value is only queried by the library at the time a
 call to \fortinline|psb_cdall| is executed, therefore changing the threshold
 has no effect on communication descriptors that have already been