Recurrent Neural Network - RNN

\[h_t=f(Wx_t+U h_{t-1}+b)\]

LSTM

Long Short-term Memory (Neural Computation 1997)
vanilla RNNs gradients vanish or exploded during back-propagation. learning Long-Term Dependencies via cell state $C$
Understanding LSTM Networks – colah’s blog

FC-LSTM

Learning precise timing with lstm recurrent networks (JMLR 2003), Generating Sequences With Recurrent Neural Networks (2013)
fully connected LSTM with peephole connection (add $C$ parameter into calucation of $f_t$, $i_t$ and $o_t$
https://colah.github.io/posts/2015-08-Understanding-LSTMs/img/LSTM3-var-peepholes.png from colah