Merge with XU Chen branch (Don't use this! It's an incomplete version)

1. Fix minor errors.
2. Add some annotations.

source/tensor/core/shape/Merge.h

@@ -26,10 +26,10 @@
 
 namespace nts { // namespace nts(NiuTrans.Tensor)
 
-/* transform a tensor by merging it alone with a dimension, e.g., (M, N/3, 3) -> (M, N) */
+/* transform a tensor by merging it along with a dimension, e.g., (M, N/3, 3) -> (M, N) */
 void _Merge(const XTensor * s, XTensor * t, int whereToMerge, int leadingDim = -1);
 
-/* transform a tensor by merging it alone with a dimension (return an XTensor structure)
+/* transform a tensor by merging it along with a dimension (return an XTensor structure)
    e.g., (M, N/3, 3) -> (M, N) */
 XTensor Merge(const XTensor &s, int whereToMerge, int leadingDim = -1);
 

source/tensor/core/shape/Split.h

 /* NiuTrans.Tensor - an open-source tensor library
-* Copyright (C) 2017, Natural Language Processing Lab, Northestern University.
-* All rights reserved.
-*
-* Licensed under the Apache License, Version 2.0 (the "License");
-* you may not use this file except in compliance with the License.
-* You may obtain a copy of the License at
-*
-*   http://www.apache.org/licenses/LICENSE-2.0
-*
-* Unless required by applicable law or agreed to in writing, software
-* distributed under the License is distributed on an "AS IS" BASIS,
-* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-* See the License for the specific language governing permissions and
-* limitations under the License.
-*/
+ * Copyright (C) 2017, Natural Language Processing Lab, Northestern University.
+ * All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 
 /*
-* $Created by: XIAO Tong (email: xiaotong@mail.neu.edu.cn) 2018-04-24
-*/
+ * $Created by: XIAO Tong (email: xiaotong@mail.neu.edu.cn) 2018-04-24
+ */
 
 #ifndef __SPLIT_H__
 #define __SPLIT_H__

source/tensor/core/shape/Stack.cpp

@@ -85,7 +85,7 @@ XTensor Stack(const TensorList &smalls, int dim)
 {
     int count = smalls.count;
     CheckNTErrors(count > 0, "Empty list!");
-    CheckNTErrors(dim >= 0, "Illegal dimension to concatenate!");
+    CheckNTErrors(dim >= 0, "Illegal dimension to Stack!");
 
     XTensor * tensor = smalls.GetItem(0);
     int order = tensor->order + 1;
@@ -149,7 +149,7 @@ void Stack(const TensorList &smalls, XTensor &t, int dim)
 {
     int count = smalls.count;
     CheckNTErrors(count > 0, "Empty list!");
-    CheckNTErrors(dim >= 0, "Illegal dimension to concatenate!");
+    CheckNTErrors(dim >= 0, "Illegal dimension to Stack!");
 
     if (!t.isInit || !CheckStackShape(smalls, t, dim)) {
         XTensor * tensor = smalls.GetItem(0);

source/tensor/core/shape/Unsqueeze.cpp

@@ -167,6 +167,16 @@ XTensor Unsqueeze(const XTensor &a, int dim, int dSize)
     return b;
 }
 
+/*
+insert a dimension by copying the blocks for x times
+(where x is the size of the inerted dimension) (returna a XTensor structure)
+make a new tensor to keep the result and return it
+
+>> a - the input tensor
+>> b - the output tensor
+>> dim - where to insert the dimension
+>> dSize - size of the newly-inserted dimension
+*/
 void Unsqueeze(const XTensor &a, XTensor &b, int dim, int dSize)
 {
     if (!b.isInit || !CheckUnsqueezeSize(&a, &b, dim, dSize)) {