论文标题
冰冷:驯服语言gan具有谨慎的抽样策略
ColdGANs: Taming Language GANs with Cautious Sampling Strategies
论文作者
论文摘要
基于最大似然估计(MLE)的训练制度遭受已知局限性,通常会导致文本序列产生较差。这些局限性的根源是训练和推理之间的不匹配,即所谓的暴露偏见,通过仅将参考文本视为正确而加剧的暴露偏见,而在实践中,几种替代表述可能同样好。生成的对抗网络(GAN)可以减轻这些局限性,但是文本的离散性质阻碍了其对语言生成的应用:到目前为止,基于强化学习的迄今为止提出的方法已显示出表现不佳的MLE。偏离了以前的工作,我们分析了应用于文本生成的gan的探索步骤,并展示了古典抽样如何导致培训不稳定。我们建议在我们命名Coldgans的GAN框架中考虑替代性探索策略,在那里我们强迫采样接近分布模式,以使学习动态更平滑。据我们所知,提出的语言甘派第一次与MLE相比,并获得了对三个生成任务的最先进的改进,即无条件的文本生成,问题产生和抽象性摘要。
Training regimes based on Maximum Likelihood Estimation (MLE) suffer from known limitations, often leading to poorly generated text sequences. At the root of these limitations is the mismatch between training and inference, i.e. the so-called exposure bias, exacerbated by considering only the reference texts as correct, while in practice several alternative formulations could be as good. Generative Adversarial Networks (GANs) can mitigate those limitations but the discrete nature of text has hindered their application to language generation: the approaches proposed so far, based on Reinforcement Learning, have been shown to underperform MLE. Departing from previous works, we analyze the exploration step in GANs applied to text generation, and show how classical sampling results in unstable training. We propose to consider alternative exploration strategies in a GAN framework that we name ColdGANs, where we force the sampling to be close to the distribution modes to get smoother learning dynamics. For the first time, to the best of our knowledge, the proposed language GANs compare favorably to MLE, and obtain improvements over the state-of-the-art on three generative tasks, namely unconditional text generation, question generation, and abstractive summarization.