Evaluating the design space of diffusion-based generative models

Fuente: arXiv
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Autores principales: Wang, Yuqing, He, Ye, Tao, Molei
Formato: Preprint
Publicado: 2024
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author Wang, Yuqing
He, Ye
Tao, Molei
author_facet Wang, Yuqing
He, Ye
Tao, Molei
contents Most existing theoretical investigations of the accuracy of diffusion models, albeit significant, assume the score function has been approximated to a certain accuracy, and then use this a priori bound to control the error of generation. This article instead provides a first quantitative understanding of the whole generation process, i.e., both training and sampling. More precisely, it conducts a non-asymptotic convergence analysis of denoising score matching under gradient descent. In addition, a refined sampling error analysis for variance exploding models is also provided. The combination of these two results yields a full error analysis, which elucidates (again, but this time theoretically) how to design the training and sampling processes for effective generation. For instance, our theory implies a preference toward noise distribution and loss weighting in training that qualitatively agree with the ones used in [Karras et al., 2022]. It also provides perspectives on the choices of time and variance schedules in sampling: when the score is well trained, the design in [Song et al., 2021] is more preferable, but when it is less trained, the design in [Karras et al., 2022] becomes more preferable.
format Preprint
id arxiv_https___arxiv_org_abs_2406_12839
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Evaluating the design space of diffusion-based generative models
Wang, Yuqing
He, Ye
Tao, Molei
Machine Learning
Dynamical Systems
Optimization and Control
Probability
Most existing theoretical investigations of the accuracy of diffusion models, albeit significant, assume the score function has been approximated to a certain accuracy, and then use this a priori bound to control the error of generation. This article instead provides a first quantitative understanding of the whole generation process, i.e., both training and sampling. More precisely, it conducts a non-asymptotic convergence analysis of denoising score matching under gradient descent. In addition, a refined sampling error analysis for variance exploding models is also provided. The combination of these two results yields a full error analysis, which elucidates (again, but this time theoretically) how to design the training and sampling processes for effective generation. For instance, our theory implies a preference toward noise distribution and loss weighting in training that qualitatively agree with the ones used in [Karras et al., 2022]. It also provides perspectives on the choices of time and variance schedules in sampling: when the score is well trained, the design in [Song et al., 2021] is more preferable, but when it is less trained, the design in [Karras et al., 2022] becomes more preferable.
title Evaluating the design space of diffusion-based generative models
topic Machine Learning
Dynamical Systems
Optimization and Control
Probability
url https://arxiv.org/abs/2406.12839