@inproceedings{welleck-etal-2020-consistency, title = "Consistency of a Recurrent Language Model With Respect to Incomplete Decoding", author = "Welleck, Sean and Kulikov, Ilia and Kim, Jaedeok and Pang, Richard Yuanzhe and Cho, Kyunghyun", booktitle = "Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP)", month = nov, year = "2020", address = "Online", publisher = "Association for Computational Linguistics", url = "https://www.aclweb.org/anthology/2020.emnlp-main.448", pages = "5553--5568", abstract = "Despite strong performance on a variety of tasks, neural sequence models trained with maximum likelihood have been shown to exhibit issues such as length bias and degenerate repetition. We study the related issue of receiving infinite-length sequences from a recurrent language model when using common decoding algorithms. To analyze this issue, we first define inconsistency of a decoding algorithm, meaning that the algorithm can yield an infinite-length sequence that has zero probability under the model. We prove that commonly used incomplete decoding algorithms {--} greedy search, beam search, top-k sampling, and nucleus sampling {--} are inconsistent, despite the fact that recurrent language models are trained to produce sequences of finite length. Based on these insights, we propose two remedies which address inconsistency: consistent variants of top-k and nucleus sampling, and a self-terminating recurrent language model. Empirical results show that inconsistency occurs in practice, and that the proposed methods prevent inconsistency.", } @article{welleck2020consistency, title={Consistency of a Recurrent Language Model With Respect to Incomplete Decoding}, author={Welleck, Sean and Kulikov, Ilia and Kim, Jaedeok and Pang, Richard Yuanzhe and Cho, Kyunghyun}, journal={arXiv preprint arXiv:2002.02492}, year={2020} }