The Method of Lines thorn (version 2 - see below).

MoL provides generic integration methods for multiple thorns simultaneously. By providing a layer between the driver and evolution thorns, this should mean that some technical issues to do with mesh refinement can be ignored. It also allows you to choose different evolution methods (in time, at least). But the primary purpose is to unambiguously evolve models in different thorns at the same time.

This is version 2 - the one that will work with mesh refinement. It's a straight copy of HawkeCVS/Public/CactusMoL2/MoL2 and I haven't checked that it will work "as is" with the new name (one of the reasons it goes into Alpha).

At the moment the only evolution method guaranteed to work with mesh refinement is ICN, although RK2 should. The generic RK methods will do something that will be subtly wrong...

Note that the "old" way of registering variables (through the functions declared in header files) is still there. As soon as function aliasing settles down, this will be removed.

Also to be done:

Better documentation
Tidy up the code (especially the debugging statements)
Optimize
Add various useful time evolution methods.


git-svn-id: http://svn.cactuscode.org/arrangements/CactusNumerical/MoL/trunk@2 578cdeb0-5ea1-4b81-8215-5a3b8777ee0b

1 files changed, 120 insertions, 0 deletions

diff --git a/src/ICN.c b/src/ICN.c
new file mode 100644
index 0000000..a39c547
--- /dev/null
+++ b/src/ICN.c
@@ -0,0 +1,120 @@
+ /*@@
+   @file      ICN.c
+   @date      Sun May 26 04:29:07 2002
+   @author    Ian Hawke
+   @desc 
+   This implements the more efficient Iterative Crank Nicholson integrator.
+   This follows the implementation of ICN in all AEI codes and is 
+   equivalent to (but hopefully more efficient than) the generic ICN
+   integrator also implemented by MoL.
+   @enddesc 
+   @version   $Header$
+ @@*/
+
+#include "cctk.h"
+#include "cctk_Arguments.h"
+#include "cctk_Parameters.h"
+
+#include "ExternalVariables.h"
+
+static const char *rcsid = "$Header$";
+
+CCTK_FILEVERSION(CactusMoL2_MoL2_ICN_c);
+
+/********************************************************************
+ *********************     Local Data Types   ***********************
+ ********************************************************************/
+
+/********************************************************************
+ ********************* Local Routine Prototypes *********************
+ ********************************************************************/
+
+/********************************************************************
+ ***************** Scheduled Routine Prototypes *********************
+ ********************************************************************/
+
+void MoL_ICNAdd(CCTK_ARGUMENTS);
+
+/********************************************************************
+ ********************* Other Routine Prototypes *********************
+ ********************************************************************/
+
+/********************************************************************
+ *********************     Local Data   *****************************
+ ********************************************************************/
+
+/********************************************************************
+ *********************     External Routines   **********************
+ ********************************************************************/
+
+ /*@@
+   @routine    MoL_ICNAdd
+   @date       Sun May 26 04:17:23 2002
+   @author     Ian Hawke
+   @desc 
+   Performs Iterative Crank Nicholson time integration. The number of
+   steps is arbitrary.
+   @enddesc 
+   @calls     
+   @calledby   
+   @history 
+ 
+   @endhistory 
+
+@@*/
+
+void MoL_ICNAdd(CCTK_ARGUMENTS)
+{
+
+  DECLARE_CCTK_ARGUMENTS;
+  DECLARE_CCTK_PARAMETERS;
+  
+  CCTK_INT index, var;
+  CCTK_INT totalsize;
+  CCTK_REAL *OldVar;
+  CCTK_REAL *UpdateVar;
+  CCTK_REAL *RHSVar;
+  
+  /*
+  printf("Inside ICN.\nProcessor %d.\nStep %d.\nRefinement %d.\nTimestep %g.\nSpacestep %g.\nTime %g\n",
+         CCTK_MyProc(cctkGH),
+         MoL_Intermediate_Steps - *MoL_Intermediate_Step + 1,
+         *cctk_levfac,
+         cctk_delta_time,
+         CCTK_DELTA_SPACE(0),
+         cctk_time);
+  */
+
+  totalsize = cctk_lsh[0] * cctk_lsh[1] * cctk_lsh[2];
+  /*
+  printf("MoL: the ICN routine says dt = %f.\n", CCTK_DELTA_TIME);
+  */
+  for (var = 0; var < MoLNumEvolvedVariables; var++)
+  {
+    OldVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 1,
+                                          EvolvedVariableIndex[var]);
+    UpdateVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0,
+                                             EvolvedVariableIndex[var]);
+    RHSVar = (CCTK_REAL*)CCTK_VarDataPtrI(cctkGH, 0, 
+                                          RHSVariableIndex[var]);
+    
+    for (index = 0; index < totalsize; index++)
+    {
+      UpdateVar[index] = OldVar[index] + CCTK_DELTA_TIME * RHSVar[index];
+      /*
+      if (CCTK_VarIndex("wavetoymol::phi") == EvolvedVariableIndex[var]){
+        CCTK_VWarn(1,__LINE__,__FILE__,"MoL",
+                   "ICN: proc %d index %d, dt %g, oldvar %g, rhs %g, new %g\n",
+                   CCTK_MyProc(cctkGH), index,CCTK_DELTA_TIME, 
+                   OldVar[index], RHSVar[index], UpdateVar[index]);
+                   }*/
+    }
+  }
+  
+  return;
+
+}
+
+/********************************************************************
+ *********************     Local Routines   *************************
+ ********************************************************************/