我正在尝试构建一个带有注意力机制的双向RNN,用于序列分类。我在理解辅助函数方面遇到了一些问题。我看到用于训练的辅助函数需要解码器输入,但是由于我想要从整个序列中获得单个标签,我不确定应该在这里给出什么输入。目前我已经构建了以下结构:
# Encoder LSTM cells
lstm_fw_cell = rnn.BasicLSTMCell(n_hidden)
lstm_bw_cell = rnn.BasicLSTMCell(n_hidden)
# Bidirectional RNN
outputs, states = tf.nn.bidirectional_dynamic_rnn(lstm_fw_cell,
lstm_bw_cell, inputs=x,
sequence_length=seq_len, dtype=tf.float32)
# Concatenate forward and backward outputs
encoder_outputs = tf.concat(outputs,2)
# Decoder LSTM cell
decoder_cell = rnn.BasicLSTMCell(n_hidden)
# Attention mechanism
attention_mechanism = tf.contrib.seq2seq.LuongAttention(n_hidden, encoder_outputs)
attn_cell = tf.contrib.seq2seq.AttentionWrapper(decoder_cell,
attention_mechanism, attention_size=n_hidden)
name="attention_init")
# Initial attention
attn_zero = attn_cell.zero_state(batch_size=tf.shape(x)[0], dtype=tf.float32)
init_state = attn_zero.clone(cell_state=states[0])
# Helper function
helper = tf.contrib.seq2seq.TrainingHelper(inputs = ???)
# Decoding
my_decoder = tf.contrib.seq2seq.BasicDecoder(cell=attn_cell,
helper=helper,
initial_state=init_state)
decoder_outputs, decoder_states = tf.contrib.seq2seq.dynamic_decode(my_decoder)
我的输入是一个序列 [批次大小,序列长度,特征数],输出是一个具有N个可能类别的单一向量 [批次大小,n_classes]。
你知道我在这里缺少什么,或者是否可以使用seq2seq进行序列分类吗?