Sentence-Permuted Paragraph Generation

Generating paragraphs of diverse contents is important in many applications. Existing generation models produce similar contents from homogenized contexts due to the fixed left-toright sentence order. Our idea is permuting the sentence orders to improve the content diversity of multi-sentence paragraph. We propose a novel framework PermGen whose objective is to maximize the expected log-likelihood of output paragraph distributions with respect to all possible sentence orders. PermGen uses hierarchical positional embedding and designs new procedures for both training phase and inference phase. Experiments on three paragraph generation benchmarks demonstrate Per-mGen generates more diverse outputs with a higher quality than existing models.