ValueError: Dimensions must be equal, but are 16 and 28 for 'seq2seq/decoder/train/decoder/while/BasicDecoderStep/lstm_cell/MatMul_4' (op: 'MatMul') with input shapes: [2,16], [28,40]

运行tensorflow代码出错,原因是把tf.contrib.seq2seq.BasicDecoder这个函数的cell类搞错了，因为之前已经对decoder_cell这个类进行了重写，所以这里的cell类也需要改变，但是这个错误发生的原因也有很多，这里是由于类的重写导致前后类不一致，

self.decoder_cell = tf.nn.rnn_cell.LSTMCell(_num_units)

self.decoder_cell = tf.nn.rnn_cell.LSTMCell(_num_units)
with tf.variable_scope("MC"):
      mc_cell = NewMTAWrapper(self.decoder_cell, topic_embedded,self.history_memory,
            self.v, self.uf, self.query_layer,           
            self.memory_layer,ex_memory=self.memory,mask=masks)
      rollout_decoder_MC = tf.contrib.seq2seq.BasicDecoder(
                        cell=self.decoder_cell,  #should be mc_cell
                        helper=helper_MC,
                        initial_state=initial_state_MC,
                        output_layer=self.output_layer