Small optimisation: substitute division by multiplication with the inverse.

git-svn-id: http://svn.cactuscode.org/arrangements/CactusNumerical/MoL/trunk@91 578cdeb0-5ea1-4b81-8215-5a3b8777ee0b

1 files changed, 4 insertions, 2 deletions

diff --git a/src/RK3.c b/src/RK3.c
index 1ecdcf5..cf21414 100644
--- a/src/RK3.c
+++ b/src/RK3.c
@@ -262,6 +262,8 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
       }
     case 1:
       {
+        const CCTK_REAL one_third = 1.0 / 3.0;
+
         for (var = 0; var < MoLNumEvolvedVariables; var++)
         {
           OldVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1,
@@ -273,7 +275,7 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
           
           for (index = 0; index < totalsize; index++)
           {
-            UpdateVar[index] = (OldVar[index] + 2*UpdateVar[index])/3
+            UpdateVar[index] = (OldVar[index] + 2*UpdateVar[index]) * one_third
               + CCTK_DELTA_TIME * RHSVar[index];
           }
         }
@@ -305,7 +307,7 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
           
           for (index = 0; index < arraytotalsize; index++)
           {
-            UpdateVar[index] = (OldVar[index] + 2*UpdateVar[index])/3
+            UpdateVar[index] = (OldVar[index] + 2*UpdateVar[index]) * one_third
               + CCTK_DELTA_TIME * RHSVar[index];
           }
         }