Question: Which architecture do they use for the encoder and decoder?
Answer: we construct an encoder with several convolutional layers BIBREF14 followed by NIN layers BIBREF15 as the lower part in the encoder and integrate them with deep bidirectional long short-term memory (Bi-LSTM) BIBREF16 at the higher part, On the decoder side, we use a standard deep unidirectional LSTM with global attention BIBREF13 that is calculated by a multi-layer perceptron (MLP)
Alternative answer: In encoder they use convolutional, NIN and bidirectional LSTM layers and in decoder they use unidirectional LSTM