Tensorflow seq2seq 获取序列隐藏状态



我不久前才开始研究张量流。我正在研究 seq2seq 模型,并以某种方式让教程工作,但我无法获取每个句子的状态。

据我了解,seq2seq 模型采用输入序列并通过 RNN 为序列生成隐藏状态。稍后,模型使用序列的隐藏状态生成新的数据序列。

我的问题是,如果我想直接使用输入序列的隐藏状态,该怎么办? 例如,如果我有一个经过训练的模型,我应该如何获得输入序列 [token1, token2,....,token N] 的最终隐藏状态?

我已经坚持了 2 天,我尝试了许多不同的方法,但没有一种有效。

在seq2seq模型中,编码器始终是一个RNN,通过rnn.rnn调用。

对 rnn.rnn 的调用返回输出和状态,因此要获取状态,您可以这样做:

_, encoder_state = rnn.rnn(encoder_cell, encoder_inputs, dtype=dtype)

在seq2seq模块中以相同的方式完成 https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/ops/seq2seq.py#L103。

好吧,我想我的问题是我真的不知道如何以张量流风格编码,所以我有点暴力破解它。

(*代表修改地点)

在 python/ops/seq2seq 中,修改 model_with_buckets()

outputs = []
*states = []
  with ops.op_scope(all_inputs, name, "model_with_buckets"):
    for j in xrange(len(buckets)):
      if j > 0:
        vs.get_variable_scope().reuse_variables()
      bucket_encoder_inputs = [encoder_inputs[i]
                               for i in xrange(buckets[j][0])]
      bucket_decoder_inputs = [decoder_inputs[i]
                               for i in xrange(buckets[j][1])]
      *bucket_outputs, _ ,bucket_states= seq2seq(bucket_encoder_inputs,
                                  bucket_decoder_inputs)
      outputs.append(bucket_outputs)
      states.append(bucket_states)
      bucket_targets = [targets[i] for i in xrange(buckets[j][1])]
      bucket_weights = [weights[i] for i in xrange(buckets[j][1])]
      losses.append(sequence_loss(
          outputs[-1], bucket_targets, bucket_weights, num_decoder_symbols,
          softmax_loss_function=softmax_loss_function))
  return outputs, losses,*states

在 python/ops/seq2seq 中,modify embedding_attention_seq2seq()

if isinstance(feed_previous, bool):
     * outputs, states =  embedding_attention_decoder(
          decoder_inputs, encoder_states[-1], attention_states, cell,
          num_decoder_symbols, num_heads, output_size, output_projection,
          feed_previous)
      * return outputs, states, tf.constant(encoder_states[-1])
    else:  # If feed_previous is a Tensor, we construct 2 graphs and use cond.
      outputs1, states1 = embedding_attention_decoder(
          decoder_inputs, encoder_states[-1], attention_states, cell,
          num_decoder_symbols, num_heads, output_size, output_projection, True)
      vs.get_variable_scope().reuse_variables()
      outputs2, states2 = embedding_attention_decoder(
          decoder_inputs, encoder_states[-1], attention_states, cell,
          num_decoder_symbols, num_heads, output_size, output_projection, False)
      outputs = control_flow_ops.cond(feed_previous,
                                      lambda: outputs1, lambda: outputs2)
      states = control_flow_ops.cond(feed_previous,
                                     lambda: states1, lambda: states2)
      *return outputs, states, tf.constant(encoder_states[-1])

at model/rnn/translate/seq2seq_model.py modify init()

if forward_only:
     * self.outputs, self.losses, self.states = seq2seq.model_with_buckets(
          self.encoder_inputs, self.decoder_inputs, targets,
          self.target_weights, buckets, self.target_vocab_size,
          lambda x, y: seq2seq_f(x, y, True),
          softmax_loss_function=softmax_loss_function)
      # If we use output projection, we need to project outputs for decoding.
      if output_projection is not None:
        for b in xrange(len(buckets)):
          self.outputs[b] = [tf.nn.xw_plus_b(output, output_projection[0],
                                             output_projection[1])
                             for output in self.outputs[b]]
    else:
  *    self.outputs, self.losses,_  = seq2seq.model_with_buckets(
          self.encoder_inputs, self.decoder_inputs, targets,
          self.target_weights, buckets, self.target_vocab_size,
          lambda x, y: seq2seq_f(x, y, False),
          softmax_loss_function=softmax_loss_function)

在 model/rnn/translate/seq2seq_model.py 修改步骤()

if not forward_only:
      return outputs[1], outputs[2], None  # Gradient norm, loss, no outputs.
else:
      *return None, outputs[0], outputs[1:-1], outputs[-1]

完成所有这些操作后,我们可以通过调用来获取编码状态:

_, _, _,states = model.step(all_other_arguements, forward_only = True)

Bearsteak上面的答案很棒,但它基于TensorFlow-0.6,这已经过时了。所以我在 tensorflow-0.8 中更新了他的答案,这也类似于最新版本中的答案。

(*代表修改地点)

losses = []
outputs = []
*states = []
with ops.op_scope(all_inputs, name, "model_with_buckets"):
    for j, bucket in enumerate(buckets):
        with variable_scope.variable_scope(variable_scope.get_variable_scope(),
                                                                             reuse=True if j > 0 else None):
            *bucket_outputs, _ ,bucket_states= seq2seq(encoder_inputs[:bucket[0]],
                                                                    decoder_inputs[:bucket[1]])
            outputs.append(bucket_outputs)
            if per_example_loss:
                losses.append(sequence_loss_by_example(
                        outputs[-1], targets[:bucket[1]], weights[:bucket[1]],
                        softmax_loss_function=softmax_loss_function))
            else:
                losses.append(sequence_loss(
                    outputs[-1], targets[:bucket[1]], weights[:bucket[1]],
                    softmax_loss_function=softmax_loss_function))
return outputs, losses, *states

在 python/ops/seq2seq 中,modify embedding_attention_seq2seq()

if isinstance(feed_previous, bool):
    *outputs, states = embedding_attention_decoder(
                decoder_inputs, encoder_state, attention_states, cell,
                num_decoder_symbols, embedding_size, num_heads=num_heads,
                output_size=output_size, output_projection=output_projection,
                feed_previous=feed_previous,
                initial_state_attention=initial_state_attention)
    *return outputs, states, encoder_state
    # If feed_previous is a Tensor, we construct 2 graphs and use cond.
def decoder(feed_previous_bool):
    reuse = None if feed_previous_bool else True
    with variable_scope.variable_scope(variable_scope.get_variable_scope(),reuse=reuse):
        outputs, state = embedding_attention_decoder(
                decoder_inputs, encoder_state, attention_states, cell,
                num_decoder_symbols, embedding_size, num_heads=num_heads,
                output_size=output_size, output_projection=output_projection,
                feed_previous=feed_previous_bool,
                update_embedding_for_previous=False,
                initial_state_attention=initial_state_attention)
        return outputs + [state]
    outputs_and_state = control_flow_ops.cond(feed_previous, lambda: decoder(True), lambda: decoder(False))                                                                                                                                                           
    *return outputs_and_state[:-1], outputs_and_state[-1], encoder_state

在 model/rnn/translate/seq2seq_model.py 修改 init()

if forward_only:
    *self.outputs, self.losses, self.states= tf.nn.seq2seq.model_with_buckets(
            self.encoder_inputs, self.decoder_inputs, targets,
            self.target_weights, buckets, lambda x, y: seq2seq_f(x, y, True),
            softmax_loss_function=softmax_loss_function)
    # If we use output projection, we need to project outputs for decoding.
    if output_projection is not None:
        for b in xrange(len(buckets)):
            self.outputs[b] = [
                    tf.matmul(output, output_projection[0]) + output_projection[1]
                    for output in self.outputs[b]
            ]
else:
    *self.outputs, self.losses, _ = tf.nn.seq2seq.model_with_buckets(
            self.encoder_inputs, self.decoder_inputs, targets,
            self.target_weights, buckets,
            lambda x, y: seq2seq_f(x, y, False),
            softmax_loss_function=softmax_loss_function)

在 model/rnn/translate/seq2seq_model.py 修改步骤()

if not forward_only:
    return outputs[1], outputs[2], None    # Gradient norm, loss, no outputs.
else:
    *return None, outputs[0], outputs[1:], outputs[-1]    # No gradient norm, loss, outputs.

完成所有这些操作后,我们可以通过调用来获取编码状态:

_, _, output_logits, states = model.step(sess, encoder_inputs, decoder_inputs,
                                                                     target_weights, bucket_id, True)
print (states)

在 translate.py 中。

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