fix rowwise add grad op

paddle/operators/rowwise_add_op.h

@@ -63,7 +63,7 @@ class RowwiseAddGradKernel : public framework::OpKernel {
 
     // https://eigen.tuxfamily.org/dox/unsupported/TensorBase_8h_source.html
     // colwise add
-    Eigen::array<int, 1> dims{{1}}; /* dimension to reduce */
+    Eigen::array<int, 1> dims{{0}}; /* dimension to reduce */
     EigenVector<T>::Flatten(*db).device(place) = OutGrad.sum(dims);
   }
 };

python/paddle/v2/framework/tests/test_rowwise_add_op.py

@@ -20,7 +20,7 @@ class RowwiseAddGradOpTest(GradientChecker):
     def test_rowwise_add(self):
         op = create_op("rowwise_add")
         inputs = {
-            "X": np.random.uniform(0.1, 1, [10, 10]).astype("float32"),
+            "X": np.random.uniform(0.1, 1, [5, 10]).astype("float32"),
             "b": np.random.uniform(0.1, 1, [10]).astype("float32")
         }
         self.check_grad(op, inputs, set(["X", "b"]), "Out")