From 69e92b39fc612819d8b393b60581bc72a8e393ab Mon Sep 17 00:00:00 2001
From: Yancey1989 <yancey1989@gmail.com>
Date: Wed, 11 Oct 2017 20:29:44 +0800
Subject: [PATCH] add an enforce

---
 paddle/operators/sequence_concat_op.cc | 3 ++-
 paddle/operators/sequence_concat_op.h  | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/paddle/operators/sequence_concat_op.cc b/paddle/operators/sequence_concat_op.cc
index c4d681bc85..3d19471618 100644
--- a/paddle/operators/sequence_concat_op.cc
+++ b/paddle/operators/sequence_concat_op.cc
@@ -65,7 +65,8 @@ class SequenceConcatOpMaker : public framework::OpProtoAndCheckerMaker {
                  "If the level is 0, the inputs will be joined at the nested "
                  "sequence level."
                  "If the level is 1, the inputs will be joined at the "
-                 "sequence level.")
+                 "sequence level."
+                 "The level should be less than the levels of input")
         .SetDefault(0);
     AddComment(R"DOC(
     The sequence_concat operator concatenates multiple LoDTensors. 
diff --git a/paddle/operators/sequence_concat_op.h b/paddle/operators/sequence_concat_op.h
index b08699e1a1..a197a05bbb 100644
--- a/paddle/operators/sequence_concat_op.h
+++ b/paddle/operators/sequence_concat_op.h
@@ -77,6 +77,9 @@ class SequenceConcatOpKernel : public framework::OpKernel<T> {
                           "LoDTensors should be the same.");
       }
     }
+    PADDLE_ENFORCE_GT(ins[0]->NumLevels(), level,
+                      "The levels of all the input LoDTensors "
+                      "should be greater than the specify level");
 
     out->mutable_data<T>(ctx.GetPlace());
     auto out_lod = concatLoD<LoDTensor>(ins, axis, level);