Stochastic Optimal Control for Diffusion Bridges in Function Spaces

Fuente: arXiv
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Main Authors: Park, Byoungwoo, Choi, Jungwon, Lim, Sungbin, Lee, Juho
Format: Preprint
Published: 2024
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author Park, Byoungwoo
Choi, Jungwon
Lim, Sungbin
Lee, Juho
author_facet Park, Byoungwoo
Choi, Jungwon
Lim, Sungbin
Lee, Juho
contents Recent advancements in diffusion models and diffusion bridges primarily focus on finite-dimensional spaces, yet many real-world problems necessitate operations in infinite-dimensional function spaces for more natural and interpretable formulations. In this paper, we present a theory of stochastic optimal control (SOC) tailored to infinite-dimensional spaces, aiming to extend diffusion-based algorithms to function spaces. Specifically, we demonstrate how Doob's $h$-transform, the fundamental tool for constructing diffusion bridges, can be derived from the SOC perspective and expanded to infinite dimensions. This expansion presents a challenge, as infinite-dimensional spaces typically lack closed-form densities. Leveraging our theory, we establish that solving the optimal control problem with a specific objective function choice is equivalent to learning diffusion-based generative models. We propose two applications: (1) learning bridges between two infinite-dimensional distributions and (2) generative models for sampling from an infinite-dimensional distribution. Our approach proves effective for diverse problems involving continuous function space representations, such as resolution-free images, time-series data, and probability density functions.
format Preprint
id arxiv_https___arxiv_org_abs_2405_20630
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Stochastic Optimal Control for Diffusion Bridges in Function Spaces
Park, Byoungwoo
Choi, Jungwon
Lim, Sungbin
Lee, Juho
Machine Learning
Recent advancements in diffusion models and diffusion bridges primarily focus on finite-dimensional spaces, yet many real-world problems necessitate operations in infinite-dimensional function spaces for more natural and interpretable formulations. In this paper, we present a theory of stochastic optimal control (SOC) tailored to infinite-dimensional spaces, aiming to extend diffusion-based algorithms to function spaces. Specifically, we demonstrate how Doob's $h$-transform, the fundamental tool for constructing diffusion bridges, can be derived from the SOC perspective and expanded to infinite dimensions. This expansion presents a challenge, as infinite-dimensional spaces typically lack closed-form densities. Leveraging our theory, we establish that solving the optimal control problem with a specific objective function choice is equivalent to learning diffusion-based generative models. We propose two applications: (1) learning bridges between two infinite-dimensional distributions and (2) generative models for sampling from an infinite-dimensional distribution. Our approach proves effective for diverse problems involving continuous function space representations, such as resolution-free images, time-series data, and probability density functions.
title Stochastic Optimal Control for Diffusion Bridges in Function Spaces
topic Machine Learning
url https://arxiv.org/abs/2405.20630