What is the upside of using `tf.nn.rnn` instead of `tf.nn.dynamic_rnn` in TensorFlow?

问题

What is the upside of using tf.nn.rnn instead of tf.nn.dynamic_rnn?

The documentation says :

[dynamic_rnn] is functionally identical to the function rnn above, but performs fully dynamic unrolling of inputs.

Is there any case where one might prefer to use tf.nn.rnn instead of tf.nn.dynamic_rnn?

来源：https://stackoverflow.com/questions/42356027/what-is-the-upside-of-using-tf-nn-rnn-instead-of-tf-nn-dynamic-rnn-in-tensor