check that init_RHS_zero is used for RK?-MR-2-1 methodssvn

these methods assume that the RHS grid function values can be re-used in
substeps which is no longer true after MoL revision 225


git-svn-id: http://svn.cactuscode.org/arrangements/CactusNumerical/MoL/trunk@226 578cdeb0-5ea1-4b81-8215-5a3b8777ee0b

2 files changed, 24 insertions, 10 deletions

diff --git a/param.ccl b/param.ccl
index c7e134e..4406721 100644
--- a/param.ccl
+++ b/param.ccl
@@ -100,8 +100,8 @@ KEYWORD ODE_Method "The ODE method use by MoL to do time integration"
   "RK65"        :: "RK65 with error estimation"
   "RK87"        :: "RK87 with error estimation"
   "AB"          :: "Adams-Bashforth"
-  "RK2-MR-2:1"  :: "2nd order 2:1 multirate RK scheme based on RK2 due to Schlegel et al 2009"
-  "RK4-MR-2:1"  :: "3rd order 2:1 multirate RK scheme based on RK43 due to Schlegel et al 2009"
+  "RK2-MR-2:1"  :: "2nd order 2:1 multirate RK scheme based on RK2 due to Schlegel et al 2009. This requires init_RHS_zero='no'."
+  "RK4-MR-2:1"  :: "3rd order 2:1 multirate RK scheme based on RK43 due to Schlegel et al 2009. This requires init_RHS_zero='no'."
   "RK4-RK2"     :: "RK4 as fast method and RK2 as slow method"
 } "ICN"
 
diff --git a/src/ParamCheck.c b/src/ParamCheck.c
index c46343a..a1b313a 100644
--- a/src/ParamCheck.c
+++ b/src/ParamCheck.c
@@ -172,18 +172,32 @@ void MoL_ParamCheck(CCTK_ARGUMENTS)
                    "number of intermediate steps must be 1");
   }
 
-  if ( (CCTK_Equals(ODE_Method, "RK2-MR-2:1"))&&
-       ( !((MoL_Intermediate_Steps == 5) && (MoL_Num_Scratch_Levels > 4))) )
+  if ( CCTK_Equals(ODE_Method, "RK2-MR-2:1") )
   {
-    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 ( !((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 (init_RHS_zero)
+    {
+      CCTK_PARAMWARN("When using the multirate 2-1 RK2 evolver the "
+                     "parameter MoL::init_RHS_zero must be set to 'no'.");
+    }
   }
 
-  if ( (CCTK_Equals(ODE_Method, "RK4-MR-2:1"))&&
-       ( !((MoL_Intermediate_Steps == 10) && (MoL_Num_Scratch_Levels > 9))) )
+  if ( CCTK_Equals(ODE_Method, "RK4-MR-2:1") )
   {
-    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 ( !((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 (init_RHS_zero)
+    {
+      CCTK_PARAMWARN("When using the multirate 2-1 RK4 evolver the "
+                     "parameter MoL::init_RHS_zero must be set to 'no'.");
+    }
   }
 
   if ( (CCTK_Equals(ODE_Method, "RK4-RK2"))&&