<p><code>TrainingHelper</code> feeds the ground truth at every step. If you want to use decoder outputs, you can use <strong>scheduled sampling</strong> [1]. Scheduled sampling is implemented in <code>ScheduledEmbeddingTrainingHelper</code> and <code>ScheduledOutputTrainingHelper</code>, so you can use one of the two (depending on your particular application) instead of <code>TrainingHelper</code>. See also this thread here: 
<a href="https://stackoverflow.com/questions/43795423/scheduled-sampling-in-tensorflow">scheduled sampling in Tensorflow</a>. </p>

<p>[1] <a href="https://arxiv.org/pdf/1506.03099.pdf" rel="noreferrer">https://arxiv.org/pdf/1506.03099.pdf</a></p>
Trouble understanding tf.contrib.seq2seq.TrainingHelper
<p>I managed to build a <strong>sequence to sequence</strong> model in <strong>tensorflow</strong> using the <strong>tf.contrib.seq2seq</strong> classes in 1.1 version. <br> <br>
For know I use the <strong>TrainingHelper</strong> for training my model.
But does this helper feed <strong>previously decoded</strong> values in the decoder for training or just the ground truth?
If it doesn't how can I feed previously decoded value as input in the decoder instead of ground truth values ?</p>