Add the Classic RK3 method (as a generic method, so use Generic_Type).

Agrees with other RK3's to floating point round off (except at
boundaries) for linear case. Uses more storage and is slower than
standard RK3 so I don't recommend it.

This showed up (so I fixed) a bug with the generic methods when used
with Carpet.


git-svn-id: http://svn.cactuscode.org/arrangements/CactusNumerical/MoL/trunk@72 578cdeb0-5ea1-4b81-8215-5a3b8777ee0b

1 files changed, 32 insertions, 3 deletions

diff --git a/src/RKCoefficients.c b/src/RKCoefficients.c
index 905fb60..57ac38a 100644
--- a/src/RKCoefficients.c
+++ b/src/RKCoefficients.c
@@ -73,7 +73,36 @@ int MoL_SetupRKCoefficients(CCTK_ARGUMENTS)
 
   CCTK_INT ierr, options_table;
 
-  if (CCTK_Equals(Generic_Type,"ICN")) 
+  if (CCTK_EQUALS(Generic_Type,"Classic RK3"))
+  {
+    if (MoL_Num_Scratch_Levels != 2)
+    {
+      CCTK_WARN(0, "For Classic RK3, MoL_Num_Scratch_Levels "
+                "should be at least 2");
+    }
+    if (MoL_Intermediate_Steps != 3)
+    {
+      CCTK_WARN(0, "For Classic RK3, MoL_Intermediate_Steps "
+                "should be at least 3");
+    }
+    for (i = 0; i < MoL_Intermediate_Steps; i++) 
+    {
+      for (j = 0; j < MoL_Num_Scratch_Levels + 1; j++) 
+      {  
+        RKAlphaCoefficients[i * MoL_Intermediate_Steps + j] = 0.0;
+      }
+      RKBetaCoefficients[i] = 0.0;
+    }
+    RKAlphaCoefficients[0] = 1.0;
+    RKAlphaCoefficients[3] = 1.0;
+    RKAlphaCoefficients[6] = 1.0 / 9.0;
+    RKAlphaCoefficients[7] = 4.0 / 9.0;
+    RKAlphaCoefficients[8] = 4.0 / 9.0;
+    RKBetaCoefficients[0] = 0.5;
+    RKBetaCoefficients[1] = 0.75;
+    RKBetaCoefficients[2] = 4.0 / 9.0;    
+  }
+  else if (CCTK_EQUALS(Generic_Type,"ICN")) 
   {
     for (i = 0; i < MoL_Intermediate_Steps; i++) 
     {
@@ -92,7 +121,7 @@ int MoL_SetupRKCoefficients(CCTK_ARGUMENTS)
       } 
     }
   }
-  else if (CCTK_Equals(Generic_Type,"RK")) 
+  else if (CCTK_EQUALS(Generic_Type,"RK")) 
   {
     if (MoL_Num_Scratch_Levels < MoL_Intermediate_Steps - 1)
     {
@@ -152,7 +181,7 @@ int MoL_SetupRKCoefficients(CCTK_ARGUMENTS)
               "with MoL_Intermediate_Steps greater than 4");
     }
   }
-  else if (CCTK_Equals(Generic_Type,"Table")) 
+  else if (CCTK_EQUALS(Generic_Type,"Table")) 
   {
     if (MoL_Num_Scratch_Levels < MoL_Intermediate_Steps - 1)
     {