add tests to check the gradient of set_subtensor

theano/tensor/tests/test_inc_subtensor.py

@@ -115,3 +115,32 @@ class Test_inc_subtensor(unittest.TestCase):
                 inc_slice(2, 1),
                 (numpy.asarray([[0,1],[2,3],[4,5.]]),
                     numpy.asarray(9.),))
+
+    def test_grad_set(self):
+
+
+        a = T.dvector()
+        b = T.dvector()
+
+        def set_slice(*s):
+            def just_numeric_args(a,b):
+                return T.set_subtensor(a[s], b)
+            return just_numeric_args
+
+        # vector
+        utt.verify_grad(
+                set_slice(slice(2,4,None)),
+                (numpy.asarray([0,1,2,3,4,5.]),
+                    numpy.asarray([9,9.]),))
+
+        # matrix
+        utt.verify_grad(
+                set_slice(slice(1,2,None), slice(None, None, None)),
+                (numpy.asarray([[0,1],[2,3],[4,5.]]),
+                    numpy.asarray([[9,9.]]),))
+
+        #single element
+        utt.verify_grad(
+                set_slice(2, 1),
+                (numpy.asarray([[0,1],[2,3],[4,5.]]),
+                    numpy.asarray(9.),))