Fast Structured Decoding for Sequence Models
Table 3: BLEU scores of beam approxiamtion ablation study on WMT En-De.
['CRF beam size  [ITALIC] k', '1', '2', '4', '8', '16', '32', '64', '128', '256']
An interesting question in our model design is how well the beam approximation fits the full CRF transition matrix. We conduct an ablation study of our NART-CRF model on WMT En-De task and The model is trained with CRF beam size k=64 and evaluated with different CRF beam size and rescoring candidates. We can see that k=16 has already provided a quite good approximation, as further increasing k does not bring much gain. This validates the effectiveness of our proposed beam approximation technique.