MoL: add Multirate capabilities. This add three new multirate RK schemes to MoL.

Flags indicate whether it is time to execute slow RHS computation.
For instance, in the RK4-RK2 scheme, there are 4 substeps in total, but the RK2 RHS are only evaluated in the very first and in the very last step of the four substeps.

From: Christian Reisswig, minor changes by Roland Haas



git-svn-id: http://svn.cactuscode.org/arrangements/CactusNumerical/MoL/trunk@175 578cdeb0-5ea1-4b81-8215-5a3b8777ee0b

1 files changed, 18 insertions, 0 deletions

diff --git a/src/ParamCheck.c b/src/ParamCheck.c
index 0257eb2..5ae51d6 100644
--- a/src/ParamCheck.c
+++ b/src/ParamCheck.c
@@ -159,6 +159,24 @@ void MoL_ParamCheck(CCTK_ARGUMENTS)
                    "number of intermediate steps must be 13 " 
                    "and the number of scratch levels at least 13.");
   }
+  
+  if ( (CCTK_Equals(ODE_Method, "RK2-MR-2:1"))&&( !((MoL_Intermediate_Steps == 5) || (MoL_Num_Scratch_Levels > 4))) )
+  {
+    CCTK_PARAMWARN("When using the multirate 2-1 RK2 evolver the "
+                   "number of intermediate steps must be 5 and the number of scratch levels at least 5");
+  }
+
+  if ( (CCTK_Equals(ODE_Method, "RK4-MR-2:1"))&&( !((MoL_Intermediate_Steps == 10) || (MoL_Num_Scratch_Levels > 9))) )
+  {
+    CCTK_PARAMWARN("When using the multirate 2-1 RK4 evolver the "
+                   "number of intermediate steps must be 10 and the number of scratch levels at least 10");
+  }
+
+  if ( (CCTK_Equals(ODE_Method, "RK4-RK2"))&&( !((MoL_Intermediate_Steps == 4) || (MoL_Num_Scratch_Levels > 3))) )
+  {
+    CCTK_PARAMWARN("When using the multirate RK4-RK2 evolver the "
+                   "number of intermediate steps must be 4 and the number of scratch levels at least 3");
+  }
 
   if (adaptive_stepsize)
   {