Wasserstein Convergence Guarantees for a General Class of Score-Based Generative Models

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Hauptverfasser: Gao, Xuefeng, Nguyen, Hoang M., Zhu, Lingjiong
Format: Preprint
Veröffentlicht: 2023
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author Gao, Xuefeng
Nguyen, Hoang M.
Zhu, Lingjiong
author_facet Gao, Xuefeng
Nguyen, Hoang M.
Zhu, Lingjiong
contents Score-based generative models (SGMs) is a recent class of deep generative models with state-of-the-art performance in many applications. In this paper, we establish convergence guarantees for a general class of SGMs in 2-Wasserstein distance, assuming accurate score estimates and smooth log-concave data distribution. We specialize our result to several concrete SGMs with specific choices of forward processes modelled by stochastic differential equations, and obtain an upper bound on the iteration complexity for each model, which demonstrates the impacts of different choices of the forward processes. We also provide a lower bound when the data distribution is Gaussian. Numerically, we experiment SGMs with different forward processes, some of which are newly proposed in this paper, for unconditional image generation on CIFAR-10. We find that the experimental results are in good agreement with our theoretical predictions on the iteration complexity, and the models with our newly proposed forward processes can outperform existing models.
format Preprint
id arxiv_https___arxiv_org_abs_2311_11003
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Wasserstein Convergence Guarantees for a General Class of Score-Based Generative Models
Gao, Xuefeng
Nguyen, Hoang M.
Zhu, Lingjiong
Machine Learning
Probability
Score-based generative models (SGMs) is a recent class of deep generative models with state-of-the-art performance in many applications. In this paper, we establish convergence guarantees for a general class of SGMs in 2-Wasserstein distance, assuming accurate score estimates and smooth log-concave data distribution. We specialize our result to several concrete SGMs with specific choices of forward processes modelled by stochastic differential equations, and obtain an upper bound on the iteration complexity for each model, which demonstrates the impacts of different choices of the forward processes. We also provide a lower bound when the data distribution is Gaussian. Numerically, we experiment SGMs with different forward processes, some of which are newly proposed in this paper, for unconditional image generation on CIFAR-10. We find that the experimental results are in good agreement with our theoretical predictions on the iteration complexity, and the models with our newly proposed forward processes can outperform existing models.
title Wasserstein Convergence Guarantees for a General Class of Score-Based Generative Models
topic Machine Learning
Probability
url https://arxiv.org/abs/2311.11003