Variational Schrödinger Diffusion Models

Fuente: arXiv
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Hauptverfasser: Deng, Wei, Luo, Weijian, Tan, Yixin, Biloš, Marin, Chen, Yu, Nevmyvaka, Yuriy, Chen, Ricky T. Q.
Format: Preprint
Veröffentlicht: 2024
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author Deng, Wei
Luo, Weijian
Tan, Yixin
Biloš, Marin
Chen, Yu
Nevmyvaka, Yuriy
Chen, Ricky T. Q.
author_facet Deng, Wei
Luo, Weijian
Tan, Yixin
Biloš, Marin
Chen, Yu
Nevmyvaka, Yuriy
Chen, Ricky T. Q.
contents Schrödinger bridge (SB) has emerged as the go-to method for optimizing transportation plans in diffusion models. However, SB requires estimating the intractable forward score functions, inevitably resulting in the costly implicit training loss based on simulated trajectories. To improve the scalability while preserving efficient transportation plans, we leverage variational inference to linearize the forward score functions (variational scores) of SB and restore simulation-free properties in training backward scores. We propose the variational Schrödinger diffusion model (VSDM), where the forward process is a multivariate diffusion and the variational scores are adaptively optimized for efficient transport. Theoretically, we use stochastic approximation to prove the convergence of the variational scores and show the convergence of the adaptively generated samples based on the optimal variational scores. Empirically, we test the algorithm in simulated examples and observe that VSDM is efficient in generations of anisotropic shapes and yields straighter sample trajectories compared to the single-variate diffusion. We also verify the scalability of the algorithm in real-world data and achieve competitive unconditional generation performance in CIFAR10 and conditional generation in time series modeling. Notably, VSDM no longer depends on warm-up initializations and has become tuning-friendly in training large-scale experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2405_04795
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Variational Schrödinger Diffusion Models
Deng, Wei
Luo, Weijian
Tan, Yixin
Biloš, Marin
Chen, Yu
Nevmyvaka, Yuriy
Chen, Ricky T. Q.
Machine Learning
Schrödinger bridge (SB) has emerged as the go-to method for optimizing transportation plans in diffusion models. However, SB requires estimating the intractable forward score functions, inevitably resulting in the costly implicit training loss based on simulated trajectories. To improve the scalability while preserving efficient transportation plans, we leverage variational inference to linearize the forward score functions (variational scores) of SB and restore simulation-free properties in training backward scores. We propose the variational Schrödinger diffusion model (VSDM), where the forward process is a multivariate diffusion and the variational scores are adaptively optimized for efficient transport. Theoretically, we use stochastic approximation to prove the convergence of the variational scores and show the convergence of the adaptively generated samples based on the optimal variational scores. Empirically, we test the algorithm in simulated examples and observe that VSDM is efficient in generations of anisotropic shapes and yields straighter sample trajectories compared to the single-variate diffusion. We also verify the scalability of the algorithm in real-world data and achieve competitive unconditional generation performance in CIFAR10 and conditional generation in time series modeling. Notably, VSDM no longer depends on warm-up initializations and has become tuning-friendly in training large-scale experiments.
title Variational Schrödinger Diffusion Models
topic Machine Learning
url https://arxiv.org/abs/2405.04795