An Empirical Comparison on Imitation Learning and Reinforcement Learning for Paraphrase Generation

Wanyu Du, Yangfeng Ji


Abstract
Generating paraphrases from given sentences involves decoding words step by step from a large vocabulary. To learn a decoder, supervised learning which maximizes the likelihood of tokens always suffers from the exposure bias. Although both reinforcement learning (RL) and imitation learning (IL) have been widely used to alleviate the bias, the lack of direct comparison leads to only a partial image on their benefits. In this work, we present an empirical study on how RL and IL can help boost the performance of generating paraphrases, with the pointer-generator as a base model. Experiments on the benchmark datasets show that (1) imitation learning is constantly better than reinforcement learning; and (2) the pointer-generator models with imitation learning outperform the state-of-the-art methods with a large margin.
Anthology ID:
D19-1619
Volume:
Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)
Month:
November
Year:
2019
Address:
Hong Kong, China
Editors:
Kentaro Inui, Jing Jiang, Vincent Ng, Xiaojun Wan
Venues:
EMNLP | IJCNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
6012–6018
Language:
URL:
https://aclanthology.org/D19-1619
DOI:
10.18653/v1/D19-1619
Bibkey:
Cite (ACL):
Wanyu Du and Yangfeng Ji. 2019. An Empirical Comparison on Imitation Learning and Reinforcement Learning for Paraphrase Generation. In Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP), pages 6012–6018, Hong Kong, China. Association for Computational Linguistics.
Cite (Informal):
An Empirical Comparison on Imitation Learning and Reinforcement Learning for Paraphrase Generation (Du & Ji, EMNLP-IJCNLP 2019)
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PDF:
https://aclanthology.org/D19-1619.pdf
Attachment:
 D19-1619.Attachment.zip
Code
 ddddwy/Reinforce-Paraphrase-Generation