Allow zero timelevels in STORAGE timelevels

This allows to simply set timelevels=0 to turn off storage without
having to put an "if (do_something timelevels > 0)" into schedule.ccl
files. It is also the only way to turn off storage inside of a GROUP
of SCHEDULE statement based on a condition (other than scheduling the
item twice, once with STORAGE, once without).


git-svn-id: http://svn.cactuscode.org/flesh/trunk@4774 17b73243-c579-4c4c-a9d2-2d5706c11dac

2 files changed, 13 insertions, 4 deletions

diff --git a/doc/UsersGuide/Appendices.tex b/doc/UsersGuide/Appendices.tex
index 9520fdd8..d61264fe 100644
--- a/doc/UsersGuide/Appendices.tex
+++ b/doc/UsersGuide/Appendices.tex
@@ -840,7 +840,9 @@ file. If the maximum number of timelevels is 1 (the default), this
 number may be omitted. Alternatively \var{timelevels} can be the name of a
 parameter accessible to the thorn. The parameter name is the same as used in C
 routines of the thorn, fully qualified parameter names of the form
-\texttt{\var{thorn}::\var{parameter}} are not allowed.
+\texttt{\var{thorn}::\var{parameter}} are not allowed. In this case 0 (zero)
+\var{timelevels} can be requested, which is equivalent to the {\tt STORAGE}
+statement being absent.
 
 The behaviour of an assignment statement is independent of its
 position in the schedule file (so long as it is outside a schedule
@@ -919,7 +921,9 @@ schedule [GROUP] <\var{function name}|\var{group name}> AT|IN <\var{time}> \verb
   this number may be omitted. Alternatively \var{timelevels} can be the
   name of a parameter accessible to the thorn. The parameter name is the
   same as used in C routines of the thorn, fully qualified parameter names
-  of the form \texttt{\var{thorn}::\var{parameter}} are not allowed.
+  of the form \texttt{\var{thorn}::\var{parameter}} are not allowed. In this
+  case 0 (zero) \var{timelevels} can be requested, which is equivalent to
+  the {\tt STORAGE} statement being absent.
 
   \item[{\tt TRIGGER}] List of grid variables or groups to be used as
   triggers for causing an {\tt ANALYSIS} function or group to be
diff --git a/doc/UsersGuide/ApplicationThorns.tex b/doc/UsersGuide/ApplicationThorns.tex
index 496ea2cb..e2a8e027 100644
--- a/doc/UsersGuide/ApplicationThorns.tex
+++ b/doc/UsersGuide/ApplicationThorns.tex
@@ -523,7 +523,9 @@ the number of timelevels of each group for which storage should be activated.
 Alternatively \var{timelevels} can be the name of a parameter accessible
 to the thorn. The parameter name is the same as used in C routines of the
 thorn, fully qualified parameter names of the form
-\texttt{\var{thorn}::\var{parameter}} are not allowed.
+\texttt{\var{thorn}::\var{parameter}} are not allowed. In this case 0 (zero)
+\var{timelevels} can be requested, which is equivalent to the {\tt STORAGE}
+statement being absent.
 
 \item[\texttt{TRIGGERS}] \texttt{TRIGGERS} is used when the routine is
 registered at \texttt{ANALYSIS}.  This is a special time bin; a routine
@@ -1504,7 +1506,10 @@ defining {\tt interface.ccl} file. If the maximum is 1 (the default)
 this number may be omitted. Alternatively \var{timelevels} can be the
 name of a parameter accessible to the thorn. The parameter name is the
 same as used in C routines of the thorn, fully qualified parameter names
-of the form \texttt{\var{thorn}::\var{parameter}} are not allowed.
+of the form \texttt{\var{thorn}::\var{parameter}} are not allowed. In this
+case 0 (zero) \var{timelevels} can be requested, which is equivalent to
+the {\tt STORAGE} statement being absent.
+
 \item[\texttt{TRIGGER}]
 This is only used for items scheduled at timebin \texttt{CCTK\_ANALYSIS}.
 The item will only be executed if output is due for at least one