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arXiv 2409.16632cs.LG
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用于贝叶斯神经网络的泛函随机梯度MCMC

Functional Stochastic Gradient MCMC for Bayesian Neural Networks

Australian Artificial Intelligence Institute (AAII), University of Technology Sydney(澳大利亚人工智能研究所(AAII),悉尼科技大学)

Mengjing Wu, Junyu Xuan, Jie Lu

AI总结:

针对贝叶斯神经网络参数空间推断的先验问题,提出基于新扩散动力学的泛函MCMC方案,证明了其平稳测度为目标后验,并在预测精度和不确定性量化上优于现有方法。

摘要:

贝叶斯神经网络(BNNs)的经典参数空间贝叶斯推断存在若干未解决的先验问题,例如知识编码不可处理性和深度网络中的病态行为,这可能导致不当的后验推断。为了解决这些问题,最近提出了利用泛函先验的泛函贝叶斯推断,例如新兴的泛函变分推断。除了变分方法外,随机梯度马尔可夫链蒙特卡洛(MCMC)是另一种用于BNNs的可扩展且有效的推断方法,它通过模拟连续动力学渐近地从真实后验中生成样本。然而,现有的MCMC方法仅在参数空间中运行,并继承了未解决的先验问题,而将这些动力学扩展到函数空间是一项非平凡的 undertaking。在本文中,我们引入了新颖的泛函MCMC方案,包括随机梯度版本,基于新设计的扩散动力学,该动力学可以结合更具信息量的泛函先验。此外,我们证明了这些泛函动力学的平稳测度是函数上的目标后验。与朴素的参数空间MCMC和泛函变分推断相比,我们的泛函MCMC方案在多个任务的预测精度和不确定性量化方面均展现出改进的性能。

英文摘要:

Classical parameter-space Bayesian inference for Bayesian neural networks (BNNs) suffers from several unresolved prior issues, such as knowledge encoding intractability and pathological behaviours in deep networks, which can lead to improper posterior inference. To address these issues, functional Bayesian inference has recently been proposed leveraging functional priors, such as the emerging functional variational inference. In addition to variational methods, stochastic gradient Markov Chain Monte Carlo (MCMC) is another scalable and effective inference method for BNNs to asymptotically generate samples from the true posterior by simulating continuous dynamics. However, existing MCMC methods perform solely in parameter space and inherit the unresolved prior issues, while extending these dynamics to function space is a non-trivial undertaking. In this paper, we introduce novel functional MCMC schemes, including stochastic gradient versions, based on newly designed diffusion dynamics that can incorporate more informative functional priors. Moreover, we prove that the stationary measure of these functional dynamics is the target posterior over functions. Our functional MCMC schemes demonstrate improved performance in both predictive accuracy and uncertainty quantification on several tasks compared to naive parameter-space MCMC and functional variational inference.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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