Controllable Paraphrase Generation with a Syntactic Exemplar
Table 3: Test results with WPL at different positions.
['[EMPTY]', 'BL', 'R-1', 'R-2', 'R-L', 'MET', 'ST']
We also study the effect of the position of WPL by (1) using the decoder hidden state, (2) using the concatenation of word embeddings in the syntactic encoder and the syntactic variable, (3) using the concatenation of word embeddings in the decoder and the syntactic variable, or (4) adding it on both the encoder embeddings and decoder word embeddings. In practice, we also observe that the value of WPL tends to vanish when using WPL on hidden states, which is presumably caused by the fact that LSTMs have sequence information, making the optimization of WPL trivial. We also observe that adding WPL to both the encoder and decoder brings the largest improvement.