In contrast to directional models, we impose the two constraints per feature given in figure 1: one on the feature value with respect to the sentences S in the parse disambiguation treebank and the other on the feature value with respect to logical forms L in the fluency ranking treebank.
of the constraints on training defined in figure 1, the feature weights in the reversible model distinguish, at the same time, good parses from bad parses as well as good realizations from bad realizations.