tures r sa and r opd are extracted to select a stack action (section 3.3.2) and an operand to push (section 3.3.3).
the features are the gated concatenation of following vectors: • h D t is the output of an LSTM, which encodes the history of applied actions: where res t−1 is the result from the previous stack action similar to the seq2seq model (Sutskever et al., 2014).