import tensorflow as tf


    initial_symbol = inputs.read(0)  # first symbol is BOS
    initial_input = embed(initial_symbol)
    initial_pos = tf.zeros([batch_size], tf.float32)
    initial_weights = tf.zeros(tf.shape(attention_states[align_encoder_id])[:2])
    zero_context = tf.zeros(shape=tf.shape(attention_states[align_encoder_id][:,0]))  # FIXME

    with tf.variable_scope('decoder_{}'.format(decoder.name)):
