1 files changed, 66 insertions, 0 deletions
diff --git a/src/stencil.c b/src/stencil.c
new file mode 100644
index 0000000..007a7c6
--- /dev/null
+++ b/src/stencil.c
@@ -0,0 +1,66 @@
+#include "cctk.h"
+
+#include "util_ErrorCodes.h"
+#include "util_Table.h"
+
+#include "stencil.h"
+
+
+
+/* Determine whether a boundary with the symmetry handle symbnd is a
+   "regular" symmetry boundary (where the SBP stencils should not be
+   modified), or an outer boundary (or a multi-block boundary), where
+   the SBP stencils need to be modified.  */
+
+void SBP_determine_onesided_stencil (const cGH * cctkGH, int * onesided)
+{
+  int symtable;
+  int pen_sym_handle;
+  CCTK_INT symbnd[6];
+  int ierr;
+  int d;
+  
+  symtable = SymmetryTableHandleForGrid (cctkGH);
+  if (symtable<0) {
+    CCTK_WARN(0,"Cannot get symmetry table handle -- maybe thorn SymBase is not active?");
+  }
+  
+  ierr = Util_TableGetIntArray (symtable, 6, symbnd, "symmetry_handle");
+  if (ierr!=6) {
+    CCTK_WARN(0,"Cannot get symmetry handles");
+  }
+  
+  pen_sym_handle = SymmetryHandleOfName ( "multipatch" );
+  
+  for (d=0; d<6; ++d) {
+    if (! cctkGH->cctk_bbox[d]) {
+      /* This is an inter-processor boundary */
+      onesided[d] = 0;
+    } else {
+      /* On an outer boundary (which is not a symmetry boundary),
+         symbnd < 0.  */
+      if (symbnd[d] < 0) {
+        onesided[d] = 1;
+      } else {
+        if (pen_sym_handle >= 0) {
+          /* If the symmetry boundary is a multi-block boundary, then
+             symbnd = pen_sym_handle.  However, we can only check that
+             thorn MultiPatch is active, i.e., whether pen_sym_handle
+             >= 0.  */
+          if (symbnd[d] == pen_sym_handle) {
+            onesided[d] = 1;
+          } else {
+            onesided[d] = 0;
+          }
+        } else {
+          onesided[d] = 0;
+        }
+      }
+    }
+  }
+}
+
+CCTK_FCALL void CCTK_FNAME (SBP_determine_onesided_stencil) (CCTK_POINTER_TO_CONST cctkGH, int * onesided)
+{
+  SBP_determine_onesided_stencil (cctkGH, onesided);
+}