Generalize stream only kernel

There exists a create_stream_pull_only_kernel. This could be generalized for all Access patterns

lbmpy/updatekernels.py

@@ -54,9 +54,9 @@ def create_lbm_kernel(collision_rule, input_field, output_field, accessor):
     return result
 
 
-def create_stream_pull_only_kernel(stencil, numpy_arr=None, src_field_name="src", dst_field_name="dst",
-                                   generic_layout='numpy', generic_field_type=np.float64):
-    """Creates a stream-pull kernel, without collision.
+def create_stream_only_kernel(stencil, numpy_arr=None, src_field_name="src", dst_field_name="dst",
+                              generic_layout='numpy', generic_field_type=np.float64, accessor=None):
+    """Creates a stream kernel, without collision.
 
     For parameters see function ``create_stream_pull_collide_kernel``
     """
@@ -71,15 +71,25 @@ def create_stream_pull_only_kernel(stencil, numpy_arr=None, src_field_name="src"
         src = Field.create_from_numpy_array(src_field_name, numpy_arr, index_dimensions=1)
         dst = Field.create_from_numpy_array(dst_field_name, numpy_arr, index_dimensions=1)
 
-    accessor = StreamPullTwoFieldsAccessor()
     eqs = [Assignment(a, b) for a, b in zip(accessor.write(dst, stencil), accessor.read(src, stencil))]
     return AssignmentCollection(eqs, [])
 
 
+def create_stream_pull_only_kernel(stencil, numpy_arr=None, src_field_name="src", dst_field_name="dst",
+                                   generic_layout='numpy', generic_field_type=np.float64):
+    """Creates a stream kernel with the pull scheme, without collision.
+
+    For parameters see function ``create_stream_pull_collide_kernel``
+    """
+    return create_stream_only_kernel(stencil, numpy_arr=numpy_arr, src_field_name=src_field_name,
+                                     dst_field_name=dst_field_name, generic_layout=generic_layout,
+                                     generic_field_type=generic_field_type, accessor=StreamPullTwoFieldsAccessor())
+
+
 def create_stream_pull_with_output_kernel(lb_method, src_field, dst_field, output):
     stencil = lb_method.stencil
     cqc = lb_method.conserved_quantity_computation
-    streamed = sp.symbols("streamed_:%d" % (len(stencil),))
+    streamed = sp.symbols(f"streamed_:{len(stencil)}")
     accessor = StreamPullTwoFieldsAccessor()
     stream_assignments = [Assignment(a, b) for a, b in zip(streamed, accessor.read(src_field, stencil))]
     output_eq_collection = cqc.output_equations_from_pdfs(streamed, output)