Nearly $d$-Linear Convergence Bounds for Diffusion Models via Stochastic Localization

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Hauptverfasser: Benton, Joe, De Bortoli, Valentin, Doucet, Arnaud, Deligiannidis, George
Format: Preprint
Veröffentlicht: 2023
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author Benton, Joe
De Bortoli, Valentin
Doucet, Arnaud
Deligiannidis, George
author_facet Benton, Joe
De Bortoli, Valentin
Doucet, Arnaud
Deligiannidis, George
contents Denoising diffusions are a powerful method to generate approximate samples from high-dimensional data distributions. Recent results provide polynomial bounds on their convergence rate, assuming $L^2$-accurate scores. Until now, the tightest bounds were either superlinear in the data dimension or required strong smoothness assumptions. We provide the first convergence bounds which are linear in the data dimension (up to logarithmic factors) assuming only finite second moments of the data distribution. We show that diffusion models require at most $\tilde O(\frac{d \log^2(1/δ)}{\varepsilon^2})$ steps to approximate an arbitrary distribution on $\mathbb{R}^d$ corrupted with Gaussian noise of variance $δ$ to within $\varepsilon^2$ in KL divergence. Our proof extends the Girsanov-based methods of previous works. We introduce a refined treatment of the error from discretizing the reverse SDE inspired by stochastic localization.
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id arxiv_https___arxiv_org_abs_2308_03686
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publishDate 2023
record_format arxiv
spellingShingle Nearly $d$-Linear Convergence Bounds for Diffusion Models via Stochastic Localization
Benton, Joe
De Bortoli, Valentin
Doucet, Arnaud
Deligiannidis, George
Machine Learning
Denoising diffusions are a powerful method to generate approximate samples from high-dimensional data distributions. Recent results provide polynomial bounds on their convergence rate, assuming $L^2$-accurate scores. Until now, the tightest bounds were either superlinear in the data dimension or required strong smoothness assumptions. We provide the first convergence bounds which are linear in the data dimension (up to logarithmic factors) assuming only finite second moments of the data distribution. We show that diffusion models require at most $\tilde O(\frac{d \log^2(1/δ)}{\varepsilon^2})$ steps to approximate an arbitrary distribution on $\mathbb{R}^d$ corrupted with Gaussian noise of variance $δ$ to within $\varepsilon^2$ in KL divergence. Our proof extends the Girsanov-based methods of previous works. We introduce a refined treatment of the error from discretizing the reverse SDE inspired by stochastic localization.
title Nearly $d$-Linear Convergence Bounds for Diffusion Models via Stochastic Localization
topic Machine Learning
url https://arxiv.org/abs/2308.03686