.. _chap_modern_rnn:
Modern Recurrent Neural Networks
================================
Although we have learned the basics of recurrent neural networks, they
are not sufficient for a practitioner to solve today’s sequence learning
problems. For instance, given the numerical unstability during gradient
calculation, gated recurrent neural networks much more common in
practice. We will begin by introducing two of such widely-used networks,
namely gated recurrent units (GRUs) and long short term memory (LSTM),
with illustrations using the same language modeling problem as
introduced in :numref:`chap_rnn`.
Furthermore, we will modify recurrent neural networks with a single
undirectional hidden layer. We will describe deep architectures, and
discuss the bidirectional design with both forward and backward
recursion. They are frequently adopted in modern recurrent networks.
In fact, a large portion of sequence learning problems such as automatic
speech recognition, text to speech, and machine translation, consider
both inputs and outputs to be sequences of arbitrary length. Finally, we
will take machine translation as an example, and introduce the
encoder-decoder architecture based on recurrent neural networks and
modern practices for such sequence to sequence learning problems.
.. toctree::
:maxdepth: 2
gru
lstm
deep-rnn
bi-rnn
machine-translation
encoder-decoder
seq2seq
beam-search