import tensorflow as tf

        w = w if w is not None else self.w
        b = b if b is not None else self.b

        if( self.data_format =='NCHW' ) :
            return tf.nn.bias_add(
                        tf.nn.conv2d(input_var, w,
                                    use_cudnn_on_gpu=True,data_format='NCHW',
                                    strides=self.strides, padding=self.padding),
                        b,data_format='NCHW',name=name)
        else :
