update understand_sentiment to 1.8 (#2082) (#2084)

* add cn doc of trace API

* update understand_sentiment to 1.8

doc/fluid/user_guides/nlp_case/understand_sentiment/README.cn.md

@@ -268,12 +268,12 @@ print("Loading IMDB word dict....")
 word_dict = paddle.dataset.imdb.word_dict()
 
 print ("Reading training data....")
-train_reader = paddle.batch(
-    paddle.reader.shuffle(
+train_reader = fluid.io.batch(
+    fluid.io.shuffle(
         paddle.dataset.imdb.train(word_dict), buf_size=25000),
     batch_size=BATCH_SIZE)
 print("Reading testing data....")
-test_reader = paddle.batch(
+test_reader = fluid.io.batch(
     paddle.dataset.imdb.test(word_dict), batch_size=BATCH_SIZE)
 ```
 word_dict是一个字典序列，是词和label的对应关系，运行下一行可以看到具体内容：

doc/fluid/user_guides/nlp_case/understand_sentiment/README.md

@@ -257,12 +257,12 @@ print("Loading IMDB word dict....")
 word_dict = paddle.dataset.imdb.word_dict()
 
 print ("Reading training data....")
-train_reader = paddle.batch(
-    paddle.reader.shuffle(
+train_reader = fluid.io.batch(
+    fluid.io.shuffle(
         paddle.dataset.imdb.train(word_dict), buf_size=25000),
     batch_size=BATCH_SIZE)
 print("Reading testing data....")
-test_reader = paddle.batch(
+test_reader = fluid.io.batch(
     paddle.dataset.imdb.test(word_dict), batch_size=BATCH_SIZE)
 ```
 Word_dict is a dictionary sequence, which is the correspondence between words and labels. You can see it specifically by running the next code:

doc/fluid/user_guides/nlp_case/understand_sentiment/index.cn.html

@@ -310,12 +310,12 @@ print("Loading IMDB word dict....")
 word_dict = paddle.dataset.imdb.word_dict()
 
 print ("Reading training data....")
-train_reader = paddle.batch(
-    paddle.reader.shuffle(
+train_reader = fluid.io.batch(
+    fluid.io.shuffle(
         paddle.dataset.imdb.train(word_dict), buf_size=25000),
     batch_size=BATCH_SIZE)
 print("Reading testing data....")
-test_reader = paddle.batch(
+test_reader = fluid.io.batch(
     paddle.dataset.imdb.test(word_dict), batch_size=BATCH_SIZE)
 ```
 word_dict是一个字典序列，是词和label的对应关系，运行下一行可以看到具体内容：

doc/fluid/user_guides/nlp_case/understand_sentiment/index.html

@@ -299,12 +299,12 @@ print("Loading IMDB word dict....")
 word_dict = paddle.dataset.imdb.word_dict()
 
 print ("Reading training data....")
-train_reader = paddle.batch(
-    paddle.reader.shuffle(
+train_reader = fluid.io.batch(
+    fluid.io.shuffle(
         paddle.dataset.imdb.train(word_dict), buf_size=25000),
     batch_size=BATCH_SIZE)
 print("Reading testing data....")
-test_reader = paddle.batch(
+test_reader = fluid.io.batch(
     paddle.dataset.imdb.test(word_dict), batch_size=BATCH_SIZE)
 ```
 Word_dict is a dictionary sequence, which is the correspondence between words and labels. You can see it specifically by running the next code:

doc/fluid/user_guides/nlp_case/understand_sentiment/train_conv.py

@@ -88,16 +88,16 @@ def train(use_cuda, params_dirname):
 
     print("Reading training data....")
     if args.enable_ce:
-        train_reader = paddle.batch(
+        train_reader = fluid.io.batch(
             paddle.dataset.imdb.train(word_dict), batch_size=BATCH_SIZE)
     else:
-        train_reader = paddle.batch(
-            paddle.reader.shuffle(
+        train_reader = fluid.io.batch(
+            fluid.io.shuffle(
                 paddle.dataset.imdb.train(word_dict), buf_size=25000),
             batch_size=BATCH_SIZE)
 
     print("Reading testing data....")
-    test_reader = paddle.batch(
+    test_reader = fluid.io.batch(
         paddle.dataset.imdb.test(word_dict), batch_size=BATCH_SIZE)
 
     feed_order = ['words', 'label']

doc/fluid/user_guides/nlp_case/understand_sentiment/train_dyn_rnn.py

@@ -79,16 +79,16 @@ def train(use_cuda, params_dirname):
 
     print("Reading training data....")
     if args.enable_ce:
-        train_reader = paddle.batch(
+        train_reader = fluid.io.batch(
             paddle.dataset.imdb.train(word_dict), batch_size=BATCH_SIZE)
     else:
-        train_reader = paddle.batch(
-            paddle.reader.shuffle(
+        train_reader = fluid.io.batch(
+            fluid.io.shuffle(
                 paddle.dataset.imdb.train(word_dict), buf_size=25000),
             batch_size=BATCH_SIZE)
 
     print("Reading testing data....")
-    test_reader = paddle.batch(
+    test_reader = fluid.io.batch(
         paddle.dataset.imdb.test(word_dict), batch_size=BATCH_SIZE)
 
     feed_order = ['words', 'label']

doc/fluid/user_guides/nlp_case/understand_sentiment/train_stacked_lstm.py

@@ -99,11 +99,11 @@ def train(use_cuda, params_dirname):
     print("Reading training data....")
 
     if args.enable_ce:
-        train_reader = paddle.batch(
+        train_reader = fluid.io.batch(
             paddle.dataset.imdb.train(word_dict), batch_size=BATCH_SIZE)
     else:
-        train_reader = paddle.batch(
-            paddle.reader.shuffle(
+        train_reader = fluid.io.batch(
+            fluid.io.shuffle(
                 paddle.dataset.imdb.train(word_dict), buf_size=25000),
             batch_size=BATCH_SIZE)