Refactor the helper c code from subtensor and incsubtensor

theano/tensor/basic.py

@@ -4019,7 +4019,6 @@ class Subtensor(Op):
         assert len(is_slice) <= node.inputs[0].ndim, node.inputs[0].ndim
 
         len_is_slice = len(is_slice)
-        view_ndim = node.inputs[0].ndim - (numpy.asarray(is_slice) == 0).sum()
 
         len_subtensor_spec = spec_pos()
 
@@ -4040,23 +4039,6 @@ class Subtensor(Op):
         int inner_ii = 0; // the current dimension of zview
         int outer_ii = 0; // current dimension of z
 
-        //TODO: give this Op a second output so that this view can be cached
-        //TODO: alternatively, fix the memory leak on failure
-        Py_INCREF(PyArray_DESCR(%(x)s));
-        PyArrayObject * xview = (PyArrayObject*)PyArray_NewFromDescr(
-                &PyArray_Type,
-                PyArray_DESCR(%(x)s),
-                %(view_ndim)s,
-                PyArray_DIMS(%(x)s),
-                PyArray_STRIDES(%(x)s),
-                PyArray_DATA(%(x)s),
-                %(x)s->flags,
-                NULL);
-        if (!xview)
-        {
-            %(fail)s;
-        }
-
         if ((PyArray_DIMS(xview) == PyArray_DIMS(%(x)s))
             && (PyArray_DIMS(%(x)s) != NULL))
         {
@@ -4195,12 +4177,33 @@ class Subtensor(Op):
         return (4,)
 
     def c_code(self, node, name, inputs, outputs, sub):  # DEBUG
-        part0 = self.helper_c_code(node, name, inputs, outputs, sub,
-                self.idx_list)
-
         x = inputs[0]
         z, = outputs
-        part1 = """
+        view_ndim = node.outputs[0].ndim
+        fail = sub['fail']
+
+        build_view = """
+        //TODO: give this Op a second output so that this view can be cached
+        //TODO: alternatively, fix the memory leak on failure
+        Py_INCREF(PyArray_DESCR(%(x)s));
+        PyArrayObject * xview = (PyArrayObject*)PyArray_NewFromDescr(
+                &PyArray_Type,
+                PyArray_DESCR(%(x)s),
+                %(view_ndim)s,
+                PyArray_DIMS(%(x)s),
+                PyArray_STRIDES(%(x)s),
+                PyArray_DATA(%(x)s),
+                %(x)s->flags,
+                NULL);
+        if (!xview)
+        {
+            %(fail)s;
+        }
+        """ % locals()
+        get_xview = self.helper_c_code(node, name, inputs, outputs, sub,
+                self.idx_list)
+
+        finish_view = """
         if (%(z)s) Py_DECREF(%(z)s);
         Py_INCREF(py_%(x)s);
         PyArray_BASE(xview) = py_%(x)s;
@@ -4208,7 +4211,7 @@ class Subtensor(Op):
         %(z)s = xview;
         """ % locals()
 
-        return part0 + part1
+        return build_view + "{" + get_xview + "}" + finish_view
 
     def c_code_cache_version(self):
         hv = self.helper_c_code_cache_version()
@@ -4489,7 +4492,9 @@ class IncSubtensor(Op):
         else:
             op_is_set = 0
         fail = sub['fail']
-
+        view_ndim = (node.inputs[0].ndim -
+                     numpy.sum([not isinstance(idx, slice)
+                                for idx in self.idx_list]))
         copy_input_if_necessary = """
         if (%(inplace)s)
         {
@@ -4508,6 +4513,25 @@ class IncSubtensor(Op):
         }
         """ % locals()
 
+        #Make a first view on the output, as we will write into it.
+        build_view = """
+        //TODO: give this Op a second output so that this view can be cached
+        //TODO: alternatively, fix the memory leak on failure
+        Py_INCREF(PyArray_DESCR(%(z)s));
+        PyArrayObject * xview = (PyArrayObject*)PyArray_NewFromDescr(
+                &PyArray_Type,
+                PyArray_DESCR(%(z)s),
+                %(view_ndim)s,
+                PyArray_DIMS(%(z)s),
+                PyArray_STRIDES(%(z)s),
+                PyArray_DATA(%(z)s),
+                %(z)s->flags,
+                NULL);
+        if (!xview)
+        {
+            %(fail)s;
+        }
+        """ % locals()
         # make xview actually a view of %(z)s
         get_xview = Subtensor.helper_c_code(node, name,
                 outputs[:1] + inputs[2:],
@@ -4541,7 +4565,8 @@ class IncSubtensor(Op):
         """ % locals()
 
         return (copy_input_if_necessary
-                + get_xview
+                + build_view
+                + "{" + get_xview + "}"
                 + make_modification
                 + "Py_DECREF(xview);"
                 )