In time step t and t%3 = 1, the model (policy) is required to determine the relation of the triplet; In time step t where t%3 = 2 or 0, the model is required to determine the first or second entity, which is copied from the source sentence.
the action space A is varied in different time step t. A = R, t%3 = 1 P, t%3 = 2, 0 where R is the predefined relations and P is the positions of source sentence.