Tensorflow dynamic_rnn TypeError:' Tensor'对象不可迭代

时间:2017-03-22 09:24:15

标签: machine-learning tensorflow recurrent-neural-network

我试图在TensorFlow中使用基本的LSTM。我收到以下错误:

TypeError: 'Tensor' object is not iterable.

违规行是:

rnn_outputs, final_state = tf.nn.dynamic_rnn(cell, x, sequence_length=seqlen,
                                            initial_state=init_state,)`  

我在Windows 7上使用版本1.0.1。我的输入和标签具有以下形状

x_shape = (50, 40, 18), y_shape = (50, 40)

其中:

  • 批量大小= 50
  • 序列长度= 40
  • 每步的输入矢量长度= 18

我按照以下方式构建我的图表

def build_graph(learn_rate, seq_len, state_size=32, batch_size=5):

    # use a fixed sequence length
    seqlen = tf.constant(seq_len, shape=[batch_size],dtype=tf.int32)

    # Placeholders
    x = tf.placeholder(tf.float32, [batch_size, None, 18])
    y = tf.placeholder(tf.float32, [batch_size, None])
    keep_prob = tf.constant(1.0)

    # RNN
    cell = tf.contrib.rnn.LSTMCell(state_size)
    init_state = tf.get_variable('init_state', [1, state_size],
                                initializer=tf.constant_initializer(0.0))
    init_state = tf.tile(init_state, [batch_size, 1])
    rnn_outputs, final_state = tf.nn.dynamic_rnn(cell, x, sequence_length=seqlen,
                                                initial_state=init_state,)

    # Add dropout, as the model otherwise quickly overfits
    rnn_outputs = tf.nn.dropout(rnn_outputs, keep_prob)

    # Prediction layer
    with tf.variable_scope('prediction'):
        W = tf.get_variable('W', [state_size, num_classes])
        b = tf.get_variable('b', [num_classes], initializer=tf.constant_initializer(0.0))

    preds = tf.tanh(tf.matmul(rnn_outputs, W) + b)

    # MSE
    loss = tf.square(tf.subtract(y, preds))

    # loss = tf.reduce_mean(tf.nn.sparse_softmax_cross_entropy_with_logits(logits, y))
    train_step = tf.train.AdamOptimizer(learn_rate).minimize(loss)

有谁能告诉我我错过了什么?

1 个答案:

答案 0 :(得分:1)

序列长度应该是可迭代的,例如列表或张量,而不是标量。在具体情况下,您需要将sequence length = 40替换为每个输入的长度列表。例如,如果你的第一个序列有10个步骤,第二个13和第三个18,你将传入[10, 13, 18]。这让TensorFlow的动态RNN知道要展开多少步(我相信它在内部使用了一个while循环)。