arXiv:2608.10384cs.LG2026-08

提出新型采样方法,解决重尾噪声下生成模型的逆向采样难题。

Generator-Guided Inverse Sampling for Lévy-Driven Generative Models

  • 从马尔可夫生成器角度重构跳跃过程,分离扩散、小跳与大跳成分。
  • 仅用神经网络估算大跳频率,跳幅由解析公式生成,提升可控性。
  • 适用于混合高斯与脉冲噪声场景,实测在复杂度与性能间取得平衡。

本文从马尔可夫生成器视角研究基于莱维过程的生成模型逆向采样问题。与传统扩散模型不同,莱维驱动动态具有无限跳跃活动,导致其逆过程非局部,仅凭得分信息难以刻画。通过分析前向与逆向生成器,推导出逆向跳跃分量通常为依赖状态的马尔可夫跳跃过程,受非局部密度比支配。据此设计结构化逆向采样器,将动态分解为扩散、小跳跃和大跳跃三部分。针对跳跃成分,神经网络仅用于近似大跳跃发生率,跳幅则通过解析导出的条件分布生成,提升可解释性与可控性。在此框架下引入高效实现技术,避免高维积分与采样开销。采样器进一步适配观测引导采样,应用于混合高斯与脉冲噪声下的OFDM-SISO信道估计,仿真显示在复杂度与性能间具良好权衡。

原文摘要 · Abstract (English)

This paper studies inverse sampling for Lévy-driven generative models from the perspective of Markov generators. Unlike conventional diffusion models, Lévy-driven dynamics involve infinite jump activities, which makes their reverse process nonlocal and difficult to characterize using score information alone. We address this challenge by analyzing the forward and reversed generators. It is derived that the reversed jump component generally becomes a state-dependent Markov jump process governed by a nonlocal density ratio. This observation motivates a structured reverse sampler that decomposes the dynamics into diffusion, small jump, and large jump components. Based on this characterization, we develop a computationally tractable sampler for a class of isotropic linear Lévy SDEs with symmetric $α$-stable jump components. For the jump component, the neural network is used only to amortize the rate of large jump activities, while jump amplitudes are generated from analytically derived conditional distributions, which improves interpretability and controllability. Efficient implementation techniques are further introduced under this setting to avoid expensive high-dimensional integration and sampling. The sampler is further adapted to approximate observation-guided sampling and applied to OFDM-SISO channel estimation under mixed Gaussian and impulsive noise. Simulations show robust estimation performance with a favorable tradeoff between complexity and performance.

生成模型莱维过程逆向采样信道估计

Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。