IncSubtensor: generalized the allocation of the output view

theano/sandbox/cuda/basic_ops.py

@@ -2433,6 +2433,10 @@ class GpuIncSubtensor(tensor.IncSubtensor, GpuOp):
     def copy_of_x(self, x):
         return """(CudaNdarray*) CudaNdarray_Copy(%(x)s)""" % locals()
 
+    def make_view_buffer(self, x, view_ndim):
+        return """CudaNdarray* xview = (CudaNdarray*)
+                CudaNdarray_New(%(view_ndim)s)""" % locals()
+
     def c_code_cache_version(self):
         # TODO: cooperate with parent class' C code
         return ()

theano/sandbox/cuda/cuda_ndarray.cuh

@@ -439,6 +439,10 @@ CudaNdarray_TakeFrom(CudaNdarray * self, PyObject *args);
 
 static int fprint_CudaNdarray(FILE * fd, const CudaNdarray *self);
 
+
+PyObject * CudaNdarray_View(const CudaNdarray * self);
+
+
 #endif
 /*
   Local Variables:

theano/tensor/basic.py

@@ -4575,20 +4575,14 @@ class IncSubtensor(Op):
             %(z)s = %(copy_of_x)s;        }
         """ % locals()
 
+        alloc_view_of_z = self.make_view_buffer(z, view_ndim)
+
         #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);
+        %(alloc_view_of_z)s;
         if (!xview)
         {
             %(fail)s;
@@ -4670,6 +4664,27 @@ class IncSubtensor(Op):
         return """(PyArrayObject*)PyArray_FromAny(py_%(x)s, NULL, 0, 0,
                 NPY_ARRAY_ENSURECOPY, NULL)""" % locals()
 
+    def make_view_buffer(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 """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)""" % locals()
+
 
     def infer_shape(self, node, shapes):
         return [shapes[0]]