论文标题
优化的人口蒙特卡洛
Optimized Population Monte Carlo
论文作者
论文摘要
自适应重要性采样(AIS)方法越来越多地用于在贝叶斯推论的背景下进行分布和相关棘手的积分的近似。人口蒙特卡洛(PMC)算法是AIS方法的一个子类,由于其适应性方便而广泛使用。在本文中,我们提出了一种新型算法,该算法利用PMC框架的好处,并包括更有效的自适应机制,从而利用目标分布的几何信息。特别是,新型算法适应了一组重要性密度(建议)的位置和比例参数。在每次迭代中,通过将多功能重采样策略(即使用先前加权样品的信息)与基于高级优化的方案相结合,从而对位置参数进行调整。目标分布的局部二阶信息是通过在梯度方向上充当缩放度量的预处理矩阵来合并的。采用了阻尼牛顿的方法来确保该计划的鲁棒性。所得的度量也用于更新建议的比例参数。我们讨论了拟议方法的几个关键理论基础。最后,我们在三个数值示例中展示了所提出的方法的成功性能,涉及具有挑战性的分布。
Adaptive importance sampling (AIS) methods are increasingly used for the approximation of distributions and related intractable integrals in the context of Bayesian inference. Population Monte Carlo (PMC) algorithms are a subclass of AIS methods, widely used due to their ease in the adaptation. In this paper, we propose a novel algorithm that exploits the benefits of the PMC framework and includes more efficient adaptive mechanisms, exploiting geometric information of the target distribution. In particular, the novel algorithm adapts the location and scale parameters of a set of importance densities (proposals). At each iteration, the location parameters are adapted by combining a versatile resampling strategy (i.e., using the information of previous weighted samples) with an advanced optimization-based scheme. Local second-order information of the target distribution is incorporated through a preconditioning matrix acting as a scaling metric onto a gradient direction. A damped Newton approach is adopted to ensure robustness of the scheme. The resulting metric is also used to update the scale parameters of the proposals. We discuss several key theoretical foundations for the proposed approach. Finally, we show the successful performance of the proposed method in three numerical examples, involving challenging distributions.