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arXiv 2406.09010stat.MEstat.CO
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一种几何方法用于有信息的MCMC采样

A geometric approach to informed MCMC sampling

Vivekananda Roy

AI总结:

本文提出一种基于黎曼几何和Fisher-Rao度量的MCMC采样方法,利用平方根表示构造有信息的提议密度,在多种模型上优于传统MH算法,并附带R包。

摘要:

本文开发了一个用于马尔可夫链蒙特卡洛(MCMC)的黎曼几何框架,其中利用概率密度函数(pdfs)流形上的Fisher-Rao度量,为Metropolis-Hastings(MH)算法构造有信息的提议密度。我们利用了pdfs的平方根表示,在该表示下,Fisher-Rao度量简化为单位超球面正象限上的标准$L^2$度量。平方根表示使我们能够轻松计算密度之间的测地距离,从而使得所提出的几何MCMC方法的实现变得直接。与随机游走MH盲目地使用关于目标的任何信息来提议候选状态不同,几何MH算法将无信息的基础密度(例如,随机游走提议密度)朝向目标密度的不同全局/局部近似移动,从而允许在状态空间的不同粒度级别上同时有效地探索分布。我们将所提出的几何MH算法与其他MCMC算法在各种马尔可夫链排序下进行比较,即协方差、效率、Peskun和谱间隙排序。几何算法相对于其他MH算法(如随机游走Metropolis、独立MH和Metropolis调整Langevin算法的变体)的优越性能在各种多模态、非线性和高维示例中得到了证明。特别是,我们使用广泛的模拟和真实数据应用来比较这些算法在分析混合模型、逻辑回归模型、空间广义线性混合模型和超高维贝叶斯变量选择模型中的表现。本文附带一个公开可用的R包。

英文摘要:

A Riemannian geometric framework for Markov chain Monte Carlo (MCMC) is developed where using the Fisher-Rao metric on the manifold of probability density functions (pdfs), informed proposal densities for Metropolis-Hastings (MH) algorithms are constructed. We exploit the square-root representation of pdfs under which the Fisher-Rao metric boils down to the standard $L^2$ metric on the positive orthant of the unit hypersphere. The square-root representation allows us to easily compute the geodesic distance between densities, resulting in a straightforward implementation of the proposed geometric MCMC methodology. Unlike the random walk MH that blindly proposes a candidate state using no information about the target, the geometric MH algorithms move an uninformed base density (e.g., a random walk proposal density) towards different global/local approximations of the target density, allowing effective exploration of the distribution simultaneously at different granular levels of the state space. We compare the proposed geometric MH algorithm with other MCMC algorithms for various Markov chain orderings, namely the covariance, efficiency, Peskun, and spectral gap orderings. The superior performance of the geometric algorithms over other MH algorithms like the random walk Metropolis, independent MH, and variants of Metropolis adjusted Langevin algorithms is demonstrated in the context of various multimodal, nonlinear, and high dimensional examples. In particular, we use extensive simulation and real data applications to compare these algorithms for analyzing mixture models, logistic regression models, spatial generalized linear mixed models and ultra-high dimensional Bayesian variable selection models. A publicly available R package accompanies the article.

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