论文标题

通过扩散恢复的可能性学习基于能量的模型

Learning Energy-Based Models by Diffusion Recovery Likelihood

论文作者

Gao, Ruiqi, Song, Yang, Poole, Ben, Wu, Ying Nian, Kingma, Diederik P.

论文摘要

尽管基于能量的模型(EBM)具有许多理想的特性,但高维数据集的培训和抽样仍然具有挑战性。受到扩散概率模型的最新进展的启发,我们提出了一种扩散恢复可能性方法,可以从越来越多的嘈杂版本的数据集中训练并从一系列EBM中学习和采样。每个EBM都经过恢复可能性训练,鉴于其在较高的噪声水平上的嘈杂版本,它在一定噪声水平上最大化数据的条件概率。优化恢复可能性比边缘可能性更容易触及,因为从条件分布中采样比从边际分布中取样容易得多。训练后,可以通过从高斯白噪声分布初始化的采样过程来生成合成的图像,并逐渐以降低的噪声水平降低条件分布。我们的方法在各种图像数据集上生成高富达样本。在无条件的CIFAR-10上,我们的方法达到了FID 9.58和Inception评分8.30,优于大多数gan。此外,我们证明了与以前的EBM上的工作不同,条件分布中的长期MCMC样本不会散开,并且仍然表示逼真的图像,从而使我们能够准确估计数据的归一化密度,即使是高维数据集的数据。我们的实施可在https://github.com/ruiqigao/recovery_likelihood中获得。

While energy-based models (EBMs) exhibit a number of desirable properties, training and sampling on high-dimensional datasets remains challenging. Inspired by recent progress on diffusion probabilistic models, we present a diffusion recovery likelihood method to tractably learn and sample from a sequence of EBMs trained on increasingly noisy versions of a dataset. Each EBM is trained with recovery likelihood, which maximizes the conditional probability of the data at a certain noise level given their noisy versions at a higher noise level. Optimizing recovery likelihood is more tractable than marginal likelihood, as sampling from the conditional distributions is much easier than sampling from the marginal distributions. After training, synthesized images can be generated by the sampling process that initializes from Gaussian white noise distribution and progressively samples the conditional distributions at decreasingly lower noise levels. Our method generates high fidelity samples on various image datasets. On unconditional CIFAR-10 our method achieves FID 9.58 and inception score 8.30, superior to the majority of GANs. Moreover, we demonstrate that unlike previous work on EBMs, our long-run MCMC samples from the conditional distributions do not diverge and still represent realistic images, allowing us to accurately estimate the normalized density of data even for high-dimensional datasets. Our implementation is available at https://github.com/ruiqigao/recovery_likelihood.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源