IncSubtensor: generalized selection of update flags

theano/sandbox/cuda/basic_ops.py

@@ -2431,12 +2431,32 @@ class GpuIncSubtensor(tensor.IncSubtensor, GpuOp):
             raise NotImplementedError()
 
     def copy_of_x(self, x):
+        """
+            x: a string giving the name of a C variable pointing to an array
+
+            Returns C code expression to make a copy of x.
+
+            Base class uses PyArrayObject *, subclasses may override for
+            different types of arrays.
+        """
         return """(CudaNdarray*) CudaNdarray_Copy(%(x)s)""" % locals()
 
     def make_view_buffer(self, x, view_ndim):
+        """
+            x: a string identifying an array to be viewed
+            view_ndim: a string specifying the number of dimensions
+                     to have in the view
+
+            This doesn't need to actually set up the view with the
+            right indexing; we'll do that manually later.
+        """
         return """CudaNdarray* xview = (CudaNdarray*)
                 CudaNdarray_New(%(view_ndim)s)""" % locals()
 
+    def get_update_flags(self):
+        """ Return the update_flags string to pass to helper_c_code."""
+        return ""
+
     def c_code_cache_version(self):
         # TODO: cooperate with parent class' C code
         return ()

theano/tensor/basic.py

@@ -4598,9 +4598,15 @@ class IncSubtensor(Op):
         }
         """ % locals()
         # make xview actually a view of %(z)s
-        get_xview = Subtensor.helper_c_code(node, name,
-                outputs[:1] + inputs[2:],
-                outputs, sub, self.idx_list)
+        get_xview = Subtensor.helper_c_code(
+                node=node,
+                name=name,
+                inputs=outputs[:1] + inputs[2:],
+                outputs=outputs,
+                sub=sub,
+                idx_list=self.idx_list,
+                update_flags=self.get_update_flags()
+                )
 
         make_modification = """
         if (%(op_is_set)s)
@@ -4694,6 +4700,10 @@ class IncSubtensor(Op):
                 %(x)s->flags,
                 NULL)""" % locals()
 
+    def get_update_flags(self):
+        """ Return the update_flags string to pass to helper c_code."""
+        return Subtensor.default_update_flags()
+
 
     def infer_shape(self, node, shapes):
         return [shapes[0]]