Gaussian Mixture Flow Matching Models

Fuente: arXiv
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Main Authors: Chen, Hansheng, Zhang, Kai, Tan, Hao, Xu, Zexiang, Luan, Fujun, Guibas, Leonidas, Wetzstein, Gordon, Bi, Sai
Format: Preprint
Published: 2025
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author Chen, Hansheng
Zhang, Kai
Tan, Hao
Xu, Zexiang
Luan, Fujun
Guibas, Leonidas
Wetzstein, Gordon
Bi, Sai
author_facet Chen, Hansheng
Zhang, Kai
Tan, Hao
Xu, Zexiang
Luan, Fujun
Guibas, Leonidas
Wetzstein, Gordon
Bi, Sai
contents Diffusion models approximate the denoising distribution as a Gaussian and predict its mean, whereas flow matching models reparameterize the Gaussian mean as flow velocity. However, they underperform in few-step sampling due to discretization error and tend to produce over-saturated colors under classifier-free guidance (CFG). To address these limitations, we propose a novel Gaussian mixture flow matching (GMFlow) model: instead of predicting the mean, GMFlow predicts dynamic Gaussian mixture (GM) parameters to capture a multi-modal flow velocity distribution, which can be learned with a KL divergence loss. We demonstrate that GMFlow generalizes previous diffusion and flow matching models where a single Gaussian is learned with an $L_2$ denoising loss. For inference, we derive GM-SDE/ODE solvers that leverage analytic denoising distributions and velocity fields for precise few-step sampling. Furthermore, we introduce a novel probabilistic guidance scheme that mitigates the over-saturation issues of CFG and improves image generation quality. Extensive experiments demonstrate that GMFlow consistently outperforms flow matching baselines in generation quality, achieving a Precision of 0.942 with only 6 sampling steps on ImageNet 256$\times$256.
format Preprint
id arxiv_https___arxiv_org_abs_2504_05304
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Gaussian Mixture Flow Matching Models
Chen, Hansheng
Zhang, Kai
Tan, Hao
Xu, Zexiang
Luan, Fujun
Guibas, Leonidas
Wetzstein, Gordon
Bi, Sai
Machine Learning
Computer Vision and Pattern Recognition
Diffusion models approximate the denoising distribution as a Gaussian and predict its mean, whereas flow matching models reparameterize the Gaussian mean as flow velocity. However, they underperform in few-step sampling due to discretization error and tend to produce over-saturated colors under classifier-free guidance (CFG). To address these limitations, we propose a novel Gaussian mixture flow matching (GMFlow) model: instead of predicting the mean, GMFlow predicts dynamic Gaussian mixture (GM) parameters to capture a multi-modal flow velocity distribution, which can be learned with a KL divergence loss. We demonstrate that GMFlow generalizes previous diffusion and flow matching models where a single Gaussian is learned with an $L_2$ denoising loss. For inference, we derive GM-SDE/ODE solvers that leverage analytic denoising distributions and velocity fields for precise few-step sampling. Furthermore, we introduce a novel probabilistic guidance scheme that mitigates the over-saturation issues of CFG and improves image generation quality. Extensive experiments demonstrate that GMFlow consistently outperforms flow matching baselines in generation quality, achieving a Precision of 0.942 with only 6 sampling steps on ImageNet 256$\times$256.
title Gaussian Mixture Flow Matching Models
topic Machine Learning
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2504.05304