Add static_input.

python/paddle/v2/fluid/layers/control_flow.py

@@ -1210,6 +1210,26 @@ class DynamicRNN(object):
             outputs={'Out': input_array})
         return array_read(array=input_array, i=self.step_idx)
 
+    def static_input(self, x):
+        self._assert_in_rnn_block_("static_input")
+        if not isinstance(x, Variable):
+            raise TypeError(
+                "static_input() can only take a Variable as its input")
+        if self.lod_rank_table is None:
+            raise RuntimeError(
+                "static_input() must be called after step_input().")
+        parent_block = self._parent_block_()
+        x_reordered = parent_block.create_var(
+            name=unique_name("dynamic_rnn_static_input_reordered"),
+            type=core.VarDesc.VarType.LOD_TENSOR,
+            dtype=x.dtype)
+        parent_block.append_op(
+            type='reorder_lod_tensor_by_rank',
+            inputs={'X': [x],
+                    'RankTable': [self.lod_rank_table]},
+            outputs={'Out': [x_reordered]})
+        return shrink_memory(x_reordered, self.step_idx, self.lod_rank_table)
+
     @contextlib.contextmanager
     def block(self):
         if self.status != DynamicRNN.BEFORE_RNN: