Merge pull request #2537 from carriepl/test_advincsubtensor1_grad

theano/tensor/subtensor.py

@@ -1971,6 +1971,7 @@ class AdvancedIncSubtensor1(Op):
             else:
                 gx = g_output
             gy = advanced_subtensor1(g_output, idx_list)
+            gy = _sum_grad_over_bcasted_dims(y, gy)
 
         return [gx, gy] + [DisconnectedType()()]
 

theano/tensor/tests/test_subtensor.py

@@ -1347,6 +1347,28 @@ class TestAdvancedSubtensor(unittest.TestCase):
                   [.5, .3 + 2.1, .15]]), aval
         assert numpy.allclose(gval, 3.0), gval
 
+    def test_inc_adv_subtensor1_with_broadcasting(self):
+        if inplace_increment is None:
+            raise inplace_increment_missing
+
+        inc = dscalar()
+        a = inc_subtensor(self.m[self.ix1], inc)
+        g_inc = tensor.grad(a.sum(), inc)
+
+        assert a.type == self.m.type, (a.type, self.m.type)
+        f = theano.function([self.m, self.ix1, inc], [a, g_inc],
+                            allow_input_downcast=True)
+        aval, gval = f([[.4, .9, .1],
+                        [5, 6, 7],
+                        [.5, .3, .15]],
+                       [0, 1, 0],
+                       2.1)
+        assert numpy.allclose(aval,
+                [[.4 + 2.1 * 2, .9  + 2.1 * 2, .1 + 2.1 * 2],
+                  [5 + 2.1, 6 + 2.1, 7 + 2.1],
+                  [.5, .3, .15]]), aval
+        assert numpy.allclose(gval, 9.0), gval
+
     def test_inc_adv_subtensor_with_index_broadcasting(self):
         if inplace_increment is None:
             raise inplace_increment_missing