Usage of custom boundary functor if given

This is needed to implement the Lees Edwards boundary conditions submitted in lbmpy!49 (merged). Custom boundary functors can now be created by users.

pystencils/datahandling/serial_datahandling.py

@@ -271,7 +271,7 @@ class SerialDataHandling(DataHandling):
     def synchronization_function_gpu(self, names, stencil_name=None, **_):
         return self.synchronization_function(names, stencil_name, target='gpu')
 
-    def synchronization_function(self, names, stencil=None, target=None, **_):
+    def synchronization_function(self, names, stencil=None, target=None, functor=None, **_):
         if target is None:
             target = self.default_target
         if target == 'opencl':
@@ -311,19 +311,22 @@ class SerialDataHandling(DataHandling):
 
             if len(filtered_stencil) > 0:
                 if target == 'cpu':
-                    from pystencils.slicing import get_periodic_boundary_functor
-                    result.append(get_periodic_boundary_functor(filtered_stencil, ghost_layers=gls))
+                    if functor is None:
+                        from pystencils.slicing import get_periodic_boundary_functor
+                        functor = get_periodic_boundary_functor
+                    result.append(functor(filtered_stencil, ghost_layers=gls))
                 else:
-                    from pystencils.gpucuda.periodicity import get_periodic_boundary_functor as boundary_func
-                    target = 'gpu' if not isinstance(self.array_handler, PyOpenClArrayHandler) else 'opencl'
-                    result.append(boundary_func(filtered_stencil, self._domainSize,
-                                                index_dimensions=self.fields[name].index_dimensions,
-                                                index_dim_shape=values_per_cell,
-                                                dtype=self.fields[name].dtype.numpy_dtype,
-                                                ghost_layers=gls,
-                                                target=target,
-                                                opencl_queue=self._opencl_queue,
-                                                opencl_ctx=self._opencl_ctx))
+                    if functor is None:
+                        from pystencils.gpucuda.periodicity import get_periodic_boundary_functor as functor
+                        target = 'gpu' if not isinstance(self.array_handler, PyOpenClArrayHandler) else 'opencl'
+                    result.append(functor(filtered_stencil, self._domainSize,
+                                          index_dimensions=self.fields[name].index_dimensions,
+                                          index_dim_shape=values_per_cell,
+                                          dtype=self.fields[name].dtype.numpy_dtype,
+                                          ghost_layers=gls,
+                                          target=target,
+                                          opencl_queue=self._opencl_queue,
+                                          opencl_ctx=self._opencl_ctx))
 
         if target == 'cpu':
             def result_functor():