Directed Acyclic Transformer Pre-training for High-quality Non-autoregressive Text Generation Fei Huang author Pei Ke author Minlie Huang author 2023 text journal article Transactions of the Association for Computational Linguistics continuing MIT Press Cambridge, MA periodical academic journal huang-etal-2023-directed 10.1162/tacl_a_00582 https://aclanthology.org/2023.tacl-1.53/ 2023 11 941 959