lbmpy: now can build periodicity into kernel

astnodes.py

 import sympy as sp
 from sympy.tensor import IndexedBase
 from pystencils.field import Field
-from pystencils.types import TypedSymbol, createType, get_type_from_sympy
+from pystencils.types import TypedSymbol, createType, get_type_from_sympy, createTypeFromString
 
 
 class Node(object):
@@ -301,6 +301,16 @@ class LoopOverCoordinate(Node):
     def loopCounterName(self):
         return LoopOverCoordinate.getLoopCounterName(self.coordinateToLoopOver)
 
+    @staticmethod
+    def isLoopCounterSymbol(symbol):
+        prefix = LoopOverCoordinate.LOOP_COUNTER_NAME_PREFIX
+        if not symbol.name.startswith(prefix):
+            return None
+        if symbol.dtype != createTypeFromString('int'):
+            return None
+        coordinate = int(symbol.name[len(prefix)+1:])
+        return coordinate
+
     @staticmethod
     def getLoopCounterSymbol(coordinateToLoopOver):
         return TypedSymbol(LoopOverCoordinate.getLoopCounterName(coordinateToLoopOver), 'int')

gpucuda/kernelcreation.py

 from pystencils.gpucuda.indexing import BlockIndexing
 from pystencils.transformations import resolveFieldAccesses, typeAllEquations, parseBasePointerInfo, getCommonShape
-from pystencils.astnodes import Block, KernelFunction, SympyAssignment
+from pystencils.astnodes import Block, KernelFunction, SympyAssignment, LoopOverCoordinate
 from pystencils.types import TypedSymbol, BasicType, StructType
 from pystencils import Field
 
@@ -25,7 +25,7 @@ def createCUDAKernel(listOfEquations, functionName="kernel", typeForSymbol=None,
         iterationSlice = []
         if isinstance(ghostLayers, int):
             for i in range(len(commonShape)):
-                iterationSlice.append(slice(ghostLayers[i], -ghostLayers[i] if ghostLayers[i] > 0 else None))
+                iterationSlice.append(slice(ghostLayers, -ghostLayers if ghostLayers > 0 else None))
         else:
             for i in range(len(commonShape)):
                 iterationSlice.append(slice(ghostLayers[i][0], -ghostLayers[i][1] if ghostLayers[i][1] > 0 else None))
@@ -46,6 +46,14 @@ def createCUDAKernel(listOfEquations, functionName="kernel", typeForSymbol=None,
                          fieldToBasePointerInfo=basePointerInfos)
     # add the function which determines #blocks and #threads as additional member to KernelFunction node
     # this is used by the jit
+
+    # If loop counter symbols have been explicitly used in the update equations (e.g. for built in periodicity),
+    # they are defined here
+    undefinedLoopCounters = {LoopOverCoordinate.isLoopCounterSymbol(s): s for s in ast.body.undefinedSymbols
+                             if LoopOverCoordinate.isLoopCounterSymbol(s) is not None}
+    for i, loopCounter in undefinedLoopCounters.items():
+        ast.body.insertFront(SympyAssignment(loopCounter, indexing.coordinates[i]))
+
     ast.indexing = indexing
     return ast