fix output padding conv

Author: jerrywgz

python/paddle/nn/layer/conv.py

@@ -98,7 +98,7 @@ def __init__(self,
                                                   'kernel_size')
         self._padding = padding
         self._padding_mode = padding_mode
-        self._output_padding = output_padding
+        self.output_padding = output_padding
         if dims != 1:
             self._updated_padding, self._padding_algorithm = _update_padding_nd(
                 padding, channel_last, dims)
@@ -163,8 +163,8 @@ def extra_repr(self):
             main_str += ', padding={_padding}'
         if self._padding_mode is not 'zeros':
             main_str += ', padding_mode={_padding_mode}'
-        if self._output_padding != 0:
-            main_str += ', output_padding={_output_padding}'
+        if self.output_padding != 0:
+            main_str += ', output_padding={output_padding}'
         if self._dilation != [1] * len(self._dilation):
             main_str += ', dilation={_dilation}'
         if self._groups != 1:
@@ -508,7 +508,7 @@ def forward(self, x, output_size=None):
             self.weight,
             bias=self.bias,
             output_size=output_size,
-            output_padding=self._output_padding,
+            output_padding=self.output_padding,
             padding=self._padding,
             stride=self._stride,
             dilation=self._dilation,
@@ -824,7 +824,7 @@ def __init__(self,
 
     def forward(self, x, output_size=None):
         if output_size is None:
-            output_padding = self._output_padding
+            output_padding = self.output_padding
         else:
             output_padding = 0
 
@@ -1161,7 +1161,7 @@ def __init__(self,
 
     def forward(self, x, output_size=None):
         if output_size is None:
-            output_padding = self._output_padding
+            output_padding = self.output_padding
         else:
             output_padding = 0