diff --git a/python/paddle/trainer/config_parser.py b/python/paddle/trainer/config_parser.py
index 9610e52186f4cdc4ada4e575671ac7db5bbfdde2..2079aaa89f9b31d203af820770465c8deb4068f8 100644
--- a/python/paddle/trainer/config_parser.py
+++ b/python/paddle/trainer/config_parser.py
@@ -1811,9 +1811,6 @@ class DepthwiseConvLayer(LayerBase):
         use_gpu = int(g_command_config_args.get("use_gpu", 0))
         parallel_nn = int(g_command_config_args.get("parallel_nn", 0))
 
-        # Automatically select cudnn_type for GPU and exconv for CPU
-        # if set type=conv, but still reserve the way user specify
-        # exconv or cudnn_conv manually.
         self.layer_type = "depthwise_conv"
         # need to specify layer in config
         self.config.type = self.layer_type
@@ -1824,7 +1821,7 @@ class DepthwiseConvLayer(LayerBase):
         for input_index in xrange(len(self.inputs)):
             input_layer = self.get_input_layer(input_index)
             conv_conf = self.config.inputs[input_index].conv_conf
-            #set the groups
+            #set the groups, the groups equals the input channels
             self.inputs[input_index].conv.groups = self.inputs[
                 input_index].conv.channels
             parse_conv(self.inputs[input_index].conv, input_layer.name,
diff --git a/python/paddle/trainer_config_helpers/layers.py b/python/paddle/trainer_config_helpers/layers.py
index c07c879191b439cdaa09c418ec76fe0a9d819f93..40ac3698bb20c0a68301154816bcdb0efb0d90a7 100755
--- a/python/paddle/trainer_config_helpers/layers.py
+++ b/python/paddle/trainer_config_helpers/layers.py
@@ -2337,6 +2337,7 @@ def img_depthwise_conv_layer(input,
         shared_biases=shared_biases,
         type=lt,
         **ExtraLayerAttribute.to_kwargs(layer_attr))
+
     return LayerOutput(
         name,
         lt,