fix model.py

core/model.py

@@ -139,23 +139,31 @@ class Model(object):
     def net(self, is_infer=False):
         return None
 
-    def train_net(self):
-        input_data = self.input_data(is_infer=False)
-        self._data_var = input_data
-        # if use dataset _data_loader not used
+    def _construct_reader(self, is_infer=False):
+        if is_infer:
+            self._infer_data_loader = fluid.io.DataLoader.from_generator(
+                feed_list=self._infer_data_var,
+                capacity=64,
+                use_double_buffer=False,
+                iterable=False)
+        else:
+            dataset_class = envs.get_global_env("dataset_class", None,
+                                                "train.reader")
+            if dataset_class == "DataLoader":
                 self._data_loader = fluid.io.DataLoader.from_generator(
                     feed_list=self._data_var,
                     capacity=64,
                     use_double_buffer=False,
                     iterable=False)
+
+    def train_net(self):
+        input_data = self.input_data(is_infer=False)
+        self._data_var = input_data
+        self._construct_reader(is_infer=False)
         self.net(input_data, is_infer=False)
 
     def infer_net(self):
         input_data = self.input_data(is_infer=True)
         self._infer_data_var = input_data
-        self._infer_data_loader = fluid.io.DataLoader.from_generator(
-            feed_list=self._infer_data_var,
-            capacity=64,
-            use_double_buffer=False,
-            iterable=False)
+        self._construct_reader(is_infer=True)
         self.net(input_data, is_infer=True)