import tensorflow as tf

    encode = tf.placeholder(tf.int32, shape=[None], name="encode")
    decode = tf.placeholder(tf.int32, shape=[decode_max_length + 2], name="decode")
    weight = tf.placeholder(tf.float32, shape=[decode_max_length + 1], name="weight")
    queue = tf.PaddingFIFOQueue(capacity = capacity,
