By revisiting Table 2, we can see that the average number of tokens for the ternary-relation data is Train Decode Bidir DAG LSTM 281s 27.3s GS GLSTM 36.7s 2.7s 74, which means that the baseline model has to execute 74 recurrent transition steps for calculating a hidden state for each input word.
our model only performs 5 state transitions, and calculations between each pair of nodes for one transition are parallelizable.