Recurrent neural networks have emerged as the state-of-the-art approach to approximating p(X).
the LSTM cell (Hochreiter and Schmidhuber, 1997) is a specific RNN architecture which has been shown to be effective on many tasks, including language modeling (Press and Wolf, 2017;Jozefowicz et al., 2016;Merity et al., 2016;Inan et al., 2017).