Add const and restrict qualifiers to the pointers.

Simplify some complex arithmetic.

Initialise the error variable in the RK45 integrator only after the
last iteration.


git-svn-id: http://svn.cactuscode.org/arrangements/CactusNumerical/MoL/trunk@104 578cdeb0-5ea1-4b81-8215-5a3b8777ee0b

5 files changed, 99 insertions, 94 deletions

diff --git a/src/GenericRK.c b/src/GenericRK.c
index 7d278b5..196c83e 100644
--- a/src/GenericRK.c
+++ b/src/GenericRK.c
@@ -80,18 +80,19 @@ void MoL_GenericRKAdd(CCTK_ARGUMENTS)
 #ifdef MOLDOESCOMPLEX
 
   CCTK_COMPLEX Complex_alpha, Complex_beta, Complex_Delta_Time;
-  CCTK_COMPLEX *UpdateComplexVar;
-  CCTK_COMPLEX *RHSComplexVar;
-  CCTK_COMPLEX *ScratchComplexVar;
+  CCTK_COMPLEX * restrict UpdateComplexVar;
+  CCTK_COMPLEX const * restrict RHSComplexVar;
+  CCTK_COMPLEX * restrict ScratchComplexVar;
 
 #endif
 
+  static CCTK_INT scratchspace_firstindex = -99;
   CCTK_INT index, var, scratchstep, alphaindex, scratchindex;
   CCTK_INT totalsize;
   CCTK_REAL alpha, beta;
-  CCTK_REAL *UpdateVar;
-  CCTK_REAL *RHSVar;
-  CCTK_REAL *ScratchVar;
+  CCTK_REAL * restrict UpdateVar;
+  CCTK_REAL const * restrict RHSVar;
+  CCTK_REAL * restrict ScratchVar;
 
   CCTK_INT arrayscratchlocation;
 
@@ -120,8 +121,8 @@ void MoL_GenericRKAdd(CCTK_ARGUMENTS)
     
     UpdateVar = (CCTK_REAL *)CCTK_VarDataPtrI(cctkGH, 0, 
                                               EvolvedVariableIndex[var]);
-    RHSVar = (CCTK_REAL *)CCTK_VarDataPtrI(cctkGH, 0, 
-                                           RHSVariableIndex[var]);
+    RHSVar = (CCTK_REAL const *)CCTK_VarDataPtrI(cctkGH, 0, 
+                                                 RHSVariableIndex[var]);
 /* #define MOLDEBUG 1 */
 #ifdef MOLDEBUG
     printf("In generic RK. Variable %d (%s). RHS %d (%s). beta %g.\n",
@@ -267,8 +268,8 @@ void MoL_GenericRKAdd(CCTK_ARGUMENTS)
     
     UpdateComplexVar = (CCTK_COMPLEX *)CCTK_VarDataPtrI(cctkGH, 0, 
                                                         EvolvedComplexVariableIndex[var]);
-    RHSComplexVar = (CCTK_COMPLEX *)CCTK_VarDataPtrI(cctkGH, 0, 
-                                                     RHSVariableIndex[var]);
+    RHSComplexVar = (CCTK_COMPLEX const *)CCTK_VarDataPtrI(cctkGH, 0, 
+                                                           RHSVariableIndex[var]);
 
     for (index = 0; index < totalsize; index++)
     {
@@ -345,8 +346,8 @@ void MoL_GenericRKAdd(CCTK_ARGUMENTS)
     
     UpdateVar = (CCTK_REAL *)CCTK_VarDataPtrI(cctkGH, 0, 
                                               EvolvedArrayVariableIndex[var]);
-    RHSVar = (CCTK_REAL *)CCTK_VarDataPtrI(cctkGH, 0, 
-                                           RHSArrayVariableIndex[var]);
+    RHSVar = (CCTK_REAL const *)CCTK_VarDataPtrI(cctkGH, 0, 
+                                                 RHSArrayVariableIndex[var]);
     
     groupindex = CCTK_GroupIndexFromVarI(EvolvedArrayVariableIndex[var]);
     ierr = CCTK_GroupDynamicData(cctkGH, groupindex,
diff --git a/src/InitialCopy.c b/src/InitialCopy.c
index 06a89da..f326ead 100644
--- a/src/InitialCopy.c
+++ b/src/InitialCopy.c
@@ -84,18 +84,18 @@ void MoL_InitialCopy(CCTK_ARGUMENTS)
   CCTK_INT var;
   CCTK_INT totalsize;
 
-  CCTK_REAL *CurrentVar;
-  CCTK_REAL *PreviousVar;
-  CCTK_REAL *ScratchVar;
+  CCTK_REAL       * restrict CurrentVar;
+  CCTK_REAL const * restrict PreviousVar;
+  CCTK_REAL       * restrict ScratchVar;
   CCTK_INT StorageOn;
 
   /* FIXME */
 
 #ifdef MOLDOESCOMPLEX
 
-  CCTK_COMPLEX *CurrentComplexVar;
-  CCTK_COMPLEX *PreviousComplexVar;
-  CCTK_COMPLEX *ScratchComplexVar;
+  CCTK_COMPLEX       * restrict CurrentComplexVar;
+  CCTK_COMPLEX const * restrict PreviousComplexVar;
+  CCTK_COMPLEX       * restrict ScratchComplexVar;
 
 #endif
 
@@ -128,7 +128,7 @@ void MoL_InitialCopy(CCTK_ARGUMENTS)
       CCTK_WARN(0, "The grid function does not have storage assigned.");
     }
     
-    PreviousVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1, 
+    PreviousVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1, 
                                                EvolvedVariableIndex[var]);
     CurrentVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
                                               EvolvedVariableIndex[var]);
@@ -146,7 +146,7 @@ void MoL_InitialCopy(CCTK_ARGUMENTS)
     
   for (var = 0; var < MoLNumEvolvedArrayVariables; var++)
   {
-    PreviousVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1,
+    PreviousVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1,
                                                EvolvedArrayVariableIndex[var]);
     CurrentVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
                                               EvolvedArrayVariableIndex[var]);
@@ -203,7 +203,7 @@ void MoL_InitialCopy(CCTK_ARGUMENTS)
       CCTK_WARN(0, "The grid function does not have storage assigned.");
     }
     
-    PreviousComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 1, 
+    PreviousComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 1, 
                                                EvolvedComplexVariableIndex[var]);
     CurrentComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0, 
                                               EvolvedComplexVariableIndex[var]);
@@ -244,7 +244,7 @@ void MoL_InitialCopy(CCTK_ARGUMENTS)
       CCTK_WARN(0, "The grid function does not have storage assigned.");
     }
 
-    PreviousVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1, 
+    PreviousVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1, 
                                                SandRVariableIndex[var]);
     CurrentVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
                                               SandRVariableIndex[var]);
@@ -301,7 +301,7 @@ void MoL_InitialCopy(CCTK_ARGUMENTS)
       CCTK_WARN(0, "The grid function does not have storage assigned.");
     }
 
-    PreviousComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 1, 
+    PreviousComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 1, 
                                                SandRComplexVariableIndex[var]);
     CurrentComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0, 
                                               SandRComplexVariableIndex[var]);
@@ -359,7 +359,7 @@ void MoL_InitialCopy(CCTK_ARGUMENTS)
     if (StorageOn > 1)
     {
       
-      PreviousVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1, 
+      PreviousVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1, 
                                                  ConstrainedVariableIndex[var]);
       CurrentVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                 ConstrainedVariableIndex[var]);
@@ -411,7 +411,7 @@ void MoL_InitialCopy(CCTK_ARGUMENTS)
     if (StorageOn > 1)
     {
 
-      PreviousComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 1, 
+      PreviousComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 1, 
                                                            ConstrainedComplexVariableIndex[var]);
       CurrentComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                           ConstrainedComplexVariableIndex[var]);
@@ -465,14 +465,14 @@ void MoL_InitRHS(CCTK_ARGUMENTS)
 /*   CCTK_INT i,j,k; */
   CCTK_INT totalsize;
 
-  CCTK_REAL *RHSVar;
+  CCTK_REAL * restrict RHSVar;
   CCTK_INT StorageOn;
 
   /* FIXME */
 
 #ifdef MOLDOESCOMPLEX
 
-  CCTK_COMPLEX *RHSComplexVar;
+  CCTK_COMPLEX * restsrict RHSComplexVar;
 
 #endif
 
@@ -631,8 +631,8 @@ void MoL_FillAllLevels(CCTK_ARGUMENTS)
   CCTK_INT var, level;
   CCTK_INT totalsize, arraydim;
 
-  CCTK_REAL *CurrentVar;
-  CCTK_REAL *PreviousVar;
+  CCTK_REAL const * restrict CurrentVar;
+  CCTK_REAL       * restrict PreviousVar;
 
   totalsize = 1;
   for (arraydim = 0; arraydim < cctk_dim; arraydim++)
@@ -642,7 +642,7 @@ void MoL_FillAllLevels(CCTK_ARGUMENTS)
 
   for (var = 0; var < MoLNumEvolvedVariables; var++)
   {
-    CurrentVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+    CurrentVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                               EvolvedVariableIndex[var]);
     for (level = 1; 
          level < CCTK_ActiveTimeLevelsVI(cctkGH,
@@ -661,7 +661,7 @@ void MoL_FillAllLevels(CCTK_ARGUMENTS)
 
   for (var = 0; var < MoLNumConstrainedVariables; var++)
   {
-    CurrentVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+    CurrentVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                               ConstrainedVariableIndex[var]);
     for (level = 1; level < CCTK_ActiveTimeLevelsVI(cctkGH,
                                                     ConstrainedVariableIndex[var]); level++)
@@ -678,7 +678,7 @@ void MoL_FillAllLevels(CCTK_ARGUMENTS)
 
   for (var = 0; var < MoLNumSandRVariables; var++)
   {
-    CurrentVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+    CurrentVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                               SandRVariableIndex[var]);
     for (level = 1; level < CCTK_ActiveTimeLevelsVI(cctkGH,
                                                     SandRVariableIndex[var]); 
diff --git a/src/RK2.c b/src/RK2.c
index d722623..1301e26 100644
--- a/src/RK2.c
+++ b/src/RK2.c
@@ -74,17 +74,17 @@ void MoL_RK2Add(CCTK_ARGUMENTS)
   
   CCTK_INT index, var;
   CCTK_INT totalsize;
-  CCTK_REAL *OldVar;
-  CCTK_REAL *UpdateVar;
-  CCTK_REAL *RHSVar;
+  CCTK_REAL const * restrict OldVar;
+  CCTK_REAL       * restrict UpdateVar;
+  CCTK_REAL const * restrict RHSVar;
   
   /* FIXME */
 
 #ifdef MOLDOESCOMPLEX
 
-  CCTK_COMPLEX *OldComplexVar;
-  CCTK_COMPLEX *UpdateComplexVar;
-  CCTK_COMPLEX *RHSComplexVar;
+  CCTK_COMPLEX const * restrict OldComplexVar;
+  CCTK_COMPLEX       * restrict UpdateComplexVar;
+  CCTK_COMPLEX const * restrict RHSComplexVar;
   CCTK_COMPLEX Complex_Delta_Time = CCTK_Cmplx(CCTK_DELTA_TIME, 0);
   CCTK_COMPLEX Complex_Half = CCTK_Cmplx(0.5, 0);
 
@@ -115,7 +115,7 @@ void MoL_RK2Add(CCTK_ARGUMENTS)
         {
           UpdateVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
                                                    EvolvedVariableIndex[var]);
-          RHSVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                 RHSVariableIndex[var]);
           
           for (index = 0; index < totalsize; index++)
@@ -128,7 +128,7 @@ void MoL_RK2Add(CCTK_ARGUMENTS)
         {
           UpdateVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
                                                    EvolvedArrayVariableIndex[var]);
-          RHSVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                 RHSArrayVariableIndex[var]);
           groupindex = CCTK_GroupIndexFromVarI(EvolvedArrayVariableIndex[var]);
           ierr = CCTK_GroupDynamicData(cctkGH, groupindex,
@@ -160,7 +160,7 @@ void MoL_RK2Add(CCTK_ARGUMENTS)
         {
           UpdateComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0,
                                                              EvolvedComplexVariableIndex[var]);
-          RHSComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                           RHSComplexVariableIndex[var]);
           
           for (index = 0; index < totalsize; index++)
@@ -179,11 +179,11 @@ void MoL_RK2Add(CCTK_ARGUMENTS)
       {
         for (var = 0; var < MoLNumEvolvedVariables; var++)
         {
-          OldVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1,
+          OldVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1,
                                                 EvolvedVariableIndex[var]);
           UpdateVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
                                                    EvolvedVariableIndex[var]);
-          RHSVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                 RHSVariableIndex[var]);
           
           for (index = 0; index < totalsize; index++)
@@ -195,12 +195,12 @@ void MoL_RK2Add(CCTK_ARGUMENTS)
 
         for (var = 0; var < MoLNumEvolvedArrayVariables; var++)
         {
-          OldVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1,
-                                                   EvolvedVariableIndex[var]);
+          OldVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1,
+                                                   EvolvedArrayVariableIndex[var]);
           UpdateVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
-                                                   EvolvedVariableIndex[var]);
-          RHSVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
-                                                RHSVariableIndex[var]);
+                                                   EvolvedArrayVariableIndex[var]);
+          RHSVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
+                                                RHSArrayVariableIndex[var]);
 
           groupindex = CCTK_GroupIndexFromVarI(EvolvedArrayVariableIndex[var]);
           ierr = CCTK_GroupDynamicData(cctkGH, groupindex,
@@ -231,11 +231,11 @@ void MoL_RK2Add(CCTK_ARGUMENTS)
 
         for (var = 0; var < MoLNumEvolvedComplexVariables; var++)
         {
-          OldComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 1,
+          OldComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 1,
                                                        EvolvedComplexVariableIndex[var]);
           UpdateComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0,
                                                              EvolvedComplexVariableIndex[var]);
-          RHSComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                           RHSComplexVariableIndex[var]);
           
           for (index = 0; index < totalsize; index++)
diff --git a/src/RK3.c b/src/RK3.c
index b8a8b03..68329a2 100644
--- a/src/RK3.c
+++ b/src/RK3.c
@@ -73,23 +73,21 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
   
   CCTK_INT index, var;
   CCTK_INT totalsize;
-  CCTK_REAL *OldVar;
-  CCTK_REAL *UpdateVar;
-  CCTK_REAL *RHSVar;
+  CCTK_REAL const * restrict OldVar;
+  CCTK_REAL       * restrict UpdateVar;
+  CCTK_REAL const * restrict RHSVar;
   
   /* FIXME */
 
 #ifdef MOLDOESCOMPLEX
 
-  CCTK_COMPLEX *OldComplexVar;
-  CCTK_COMPLEX *UpdateComplexVar;
-  CCTK_COMPLEX *RHSComplexVar;
+  CCTK_COMPLEX const * restrict OldComplexVar;
+  CCTK_COMPLEX       * restrict UpdateComplexVar;
+  CCTK_COMPLEX const * restrict RHSComplexVar;
   CCTK_COMPLEX Complex_Delta_Time = CCTK_Cmplx(CCTK_DELTA_TIME, 0);
   CCTK_COMPLEX Complex_Half = CCTK_Cmplx(0.5, 0);
-  CCTK_COMPLEX Complex_Third = CCTK_CmplxDiv(CCTK_Cmplx(1.0, 0),
-                                             CCTK_Cmplx(3.0,0));
-  CCTK_COMPLEX Complex_TwoThird = CCTK_CmplxDiv(CCTK_Cmplx(2.0, 0),
-                                                CCTK_Cmplx(3.0,0));
+  CCTK_COMPLEX Complex_Third = CCTK_Cmplx(1.0/3.0, 0);
+  CCTK_COMPLEX Complex_TwoThird = CCTK_Cmplx(2.0/3.0, 0);
   CCTK_COMPLEX Complex_Quarter = CCTK_Cmplx(0.25, 0);
   CCTK_COMPLEX Complex_ThreeQuarter = CCTK_Cmplx(0.75, 0);
 
@@ -185,11 +183,11 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
       {
         for (var = 0; var < MoLNumEvolvedVariables; var++)
         {
-          OldVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1,
+          OldVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1,
                                                 EvolvedVariableIndex[var]);
           UpdateVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
                                                    EvolvedVariableIndex[var]);
-          RHSVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                 RHSVariableIndex[var]);
           
           for (index = 0; index < totalsize; index++)
@@ -202,11 +200,11 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
 
         for (var = 0; var < MoLNumEvolvedArrayVariables; var++)
         {
-          OldVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1,
+          OldVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1,
                                                 EvolvedArrayVariableIndex[var]);
           UpdateVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
                                                    EvolvedArrayVariableIndex[var]);
-          RHSVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                 RHSArrayVariableIndex[var]);
           groupindex = CCTK_GroupIndexFromVarI(EvolvedArrayVariableIndex[var]);
           ierr = CCTK_GroupDynamicData(cctkGH, groupindex,
@@ -237,11 +235,11 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
 
         for (var = 0; var < MoLNumEvolvedComplexVariables; var++)
         {
-          OldComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 1,
+          OldComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 1,
                                                           EvolvedComplexVariableIndex[var]);
           UpdateComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0,
                                                              EvolvedComplexVariableIndex[var]);
-          RHSComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                           RHSComplexVariableIndex[var]);
           
           for (index = 0; index < totalsize; index++)
@@ -266,11 +264,11 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
 
         for (var = 0; var < MoLNumEvolvedVariables; var++)
         {
-          OldVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1,
+          OldVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1,
                                                 EvolvedVariableIndex[var]);
           UpdateVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
                                                    EvolvedVariableIndex[var]);
-          RHSVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                 RHSVariableIndex[var]);
           
           for (index = 0; index < totalsize; index++)
@@ -282,11 +280,11 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
 
         for (var = 0; var < MoLNumEvolvedArrayVariables; var++)
         {
-          OldVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1,
+          OldVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 1,
                                                    EvolvedArrayVariableIndex[var]);
           UpdateVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
                                                    EvolvedArrayVariableIndex[var]);
-          RHSVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSVar = (CCTK_REAL const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                 RHSArrayVariableIndex[var]);
 
           groupindex = CCTK_GroupIndexFromVarI(EvolvedArrayVariableIndex[var]);
@@ -318,11 +316,11 @@ void MoL_RK3Add(CCTK_ARGUMENTS)
 
         for (var = 0; var < MoLNumEvolvedComplexVariables; var++)
         {
-          OldComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 1,
+          OldComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 1,
                                                           EvolvedComplexVariableIndex[var]);
           UpdateComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0,
                                                              EvolvedComplexVariableIndex[var]);
-          RHSComplexVar = (CCTK_COMPLEX*)CCTK_VarDataPtrI(cctkGH, 0, 
+          RHSComplexVar = (CCTK_COMPLEX const*)CCTK_VarDataPtrI(cctkGH, 0, 
                                                           RHSComplexVariableIndex[var]);
           
           for (index = 0; index < totalsize; index++)
diff --git a/src/RK45.c b/src/RK45.c
index b2f6c88..f92159a 100644
--- a/src/RK45.c
+++ b/src/RK45.c
@@ -74,11 +74,11 @@ void MoL_RK45Add(CCTK_ARGUMENTS)
   CCTK_INT index, var, scratchstep, alphaindex, scratchindex;
   CCTK_INT totalsize;
 
-  CCTK_REAL *UpdateVar;
-  CCTK_REAL *RHSVar;
-  CCTK_REAL *ScratchVar;
-  CCTK_REAL *ErrorVar;
-  CCTK_REAL *OldVar;
+  CCTK_REAL       * restrict UpdateVar;
+  CCTK_REAL const * restrict RHSVar;
+  CCTK_REAL       * restrict ScratchVar;
+  CCTK_REAL       * restrict ErrorVar;
+  CCTK_REAL const * restrict OldVar;
 
   CCTK_INT arrayscratchlocation;
 
@@ -126,8 +126,8 @@ void MoL_RK45Add(CCTK_ARGUMENTS)
 
     UpdateVar = (CCTK_REAL *)CCTK_VarDataPtrI(cctkGH, 0, 
                                               EvolvedVariableIndex[var]);
-    RHSVar = (CCTK_REAL *)CCTK_VarDataPtrI(cctkGH, 0, 
-                                           RHSVariableIndex[var]);
+    RHSVar = (CCTK_REAL const *)CCTK_VarDataPtrI(cctkGH, 0, 
+						 RHSVariableIndex[var]);
     ScratchVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
                                               CCTK_FirstVarIndex("MOL::SCRATCHSPACE")
                                               + var 
@@ -143,29 +143,28 @@ void MoL_RK45Add(CCTK_ARGUMENTS)
 
   for (var = 0; var < MoLNumEvolvedVariables; var++)
   {
-    OldVar = (CCTK_REAL *)CCTK_VarDataPtrI(cctkGH, 1, 
-                                           EvolvedVariableIndex[var]);
+    OldVar = (CCTK_REAL const *)CCTK_VarDataPtrI(cctkGH, 1, 
+						 EvolvedVariableIndex[var]);
     UpdateVar = (CCTK_REAL *)CCTK_VarDataPtrI(cctkGH, 0, 
                                               EvolvedVariableIndex[var]);
-    RHSVar = (CCTK_REAL *)CCTK_VarDataPtrI(cctkGH, 0, 
-                                              CCTK_FirstVarIndex("MOL::SCRATCHSPACE")
-                                              + var 
-                                              + MoL_Num_Evolved_Vars * 
-                                              (MoL_Intermediate_Steps - 
-                                               (*MoL_Intermediate_Step)));
+    RHSVar = (CCTK_REAL const *)CCTK_VarDataPtrI(cctkGH, 0, 
+						 CCTK_FirstVarIndex("MOL::SCRATCHSPACE")
+						 + var 
+						 + MoL_Num_Evolved_Vars * 
+						 (MoL_Intermediate_Steps - 
+						  (*MoL_Intermediate_Step)));
     ErrorVar =  (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
                                              CCTK_FirstVarIndex("MOL::ERRORESTIMATE")
                                              + var);
-    
-    for (index = 0; index < totalsize; index++)
-    {
-      UpdateVar[index] = OldVar[index];
-      ErrorVar[index] = 0;
-    }
-    
+
     if (*MoL_Intermediate_Step - 1)
     { 
 
+      for (index = 0; index < totalsize; index++)
+      {
+        UpdateVar[index] = OldVar[index];
+      }
+
       for (scratchstep = 0; 
            scratchstep < MoL_Intermediate_Steps - (*MoL_Intermediate_Step) + 1;
            scratchstep++)
@@ -191,6 +190,13 @@ void MoL_RK45Add(CCTK_ARGUMENTS)
     }
     else
     {
+
+      for (index = 0; index < totalsize; index++)
+      {
+        UpdateVar[index] = OldVar[index];
+        ErrorVar[index] = 0;
+      }
+    
       for (scratchstep = 0; scratchstep < 6; scratchstep++)
       {