Improve performance of Fortran index calculations

In Fortran, Cactus currently declares grid functions e.g. as (this is
the expansion of DECLARE_CCTK_ARGUMENTS)

   REAL*8 gxx (X0metric,X1metric,X2metric)

where X0metric etc. are integers passed into the routine. Each grid
function group has its own, independent size. This has two
disadvantages:

- The compiler does not know that all grid functions have the same
  size (namely cctk_lsh), and thus has to perform array index
  calculations separately for each group
- The argument list is longer than neded

The enclosed patch declares grid functions via cctk_lsh. Grid arrays
are still declared independently.

This reduces the code size of e.g. GRHydro/GRHydro_Tmunu.F90 from 6836
to 6241 bytes on my system. I have not attempted to measure a
performance difference.


git-svn-id: http://svn.cactuscode.org/flesh/trunk@4763 17b73243-c579-4c4c-a9d2-2d5706c11dac

1 files changed, 25 insertions, 7 deletions

diff --git a/lib/sbin/GridFuncStuff.pl b/lib/sbin/GridFuncStuff.pl
index d12831ed..f564d954 100644
--- a/lib/sbin/GridFuncStuff.pl
+++ b/lib/sbin/GridFuncStuff.pl
@@ -381,19 +381,37 @@ sub GetThornArguments
         {
 # FIXME: quick hack to shorten argument names
 #          $type .= "${sep}cctkv$dim$group";
-          $type .= "${sep}X$dim$group";
-          $sep = ',';
-          if($block eq 'PRIVATE')
+          if ($gtype ne 'GF')
           {
-# FIXME: quick hack to shorten argument names
-#            $arguments{"cctkv$dim$group"} = "(STORAGESIZE($thorn\::$group, $dim))";
-            $arguments{"X$dim$group"} = "(STORAGESIZE($thorn\::$group, $dim))";
+            $type .= "${sep}X$dim$group";
           }
           else
           {
+            my $dim1=$dim+1;
+            if ($dim<3)
+            {
+              $type .= "${sep}cctk_lsh$dim1";
+            }
+            else
+            {
+              $type .= "${sep}cctk_lsh($dim1)";
+            }
+          }
+          $sep = ',';
+          if ($gtype ne 'GF')
+          {
+            if($block eq 'PRIVATE')
+            {
+# FIXME: quick hack to shorten argument names
+#            $arguments{"cctkv$dim$group"} = "(STORAGESIZE($thorn\::$group, $dim))";
+              $arguments{"X$dim$group"} = "(STORAGESIZE($thorn\::$group, $dim))";
+            }
+            else
+            {
 # FIXME: quick hack to shorten argument names
 #            $arguments{"cctkv$dim$group"} = "(STORAGESIZE($imp\::$group, $dim))";
-            $arguments{"X$dim$group"} = "(STORAGESIZE($imp\::$group, $dim))";
+              $arguments{"X$dim$group"} = "(STORAGESIZE($imp\::$group, $dim))";
+            }
           }
         }
         if(defined($vararraysize) && $compactgroup == 0)