Fix output dims of sequence expand op

Author: wanghaoshuang

paddle/operators/sequence_expand_op.cc

@@ -29,7 +29,9 @@ class SequenceExpandOp : public framework::OperatorWithKernel {
     PADDLE_ENFORCE(ctx->HasOutput("Out"));
     PADDLE_ENFORCE(ctx->HasInput("Y"));
     framework::DDim out_dim;
-    out_dim = ctx->GetInputDim("Y");
+    auto y_dim = ctx->GetInputDim("Y");
+    out_dim = ctx->GetInputDim("X");
+    out_dim[0] = y_dim[0];
     ctx->ShareLoD("Y", "Out");
     ctx->SetOutputDim("Out", out_dim);
   }

python/paddle/v2/fluid/tests/test_sequence_expand.py

@@ -73,5 +73,20 @@ def set_data(self):
         self.inputs = {'X': (x_data, x_lod), 'Y': (y_data, y_lod)}
 
 
+class TestSequenceExpandCase4(TestSequenceExpand):
+    def set_data(self):
+        x_data = np.array(
+            [0.1, 0.3, 0.2, 0.15, 0.25, 0.2, 0.15, 0.25, 0.1, 0.3]).reshape(
+                [2, 5]).astype('float32')
+        x_lod = [[
+            0,
+            1,
+            2,
+        ]]
+        y_data = np.random.uniform(0.1, 1, [2, 1]).astype('float32')
+        y_lod = [[0, 1, 2], [0, 1, 2]]
+        self.inputs = {'X': (x_data, x_lod), 'Y': (y_data, y_lod)}
+
+
 if __name__ == '__main__':
     unittest.main()