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arXiv 1808.04739stat.CO
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用一个基于concept的Gibbs抽样器模拟马尔可夫随机场

Simulating Markov random fields with a conclique-based Gibbs sampler

Andee Kaplan, Mark S. Kaiser, Soumendra N. Lahiri, Daniel J. Nordman

摘要:

对于空间和网络数据,我们考虑由马尔可夫随机场(MRF)结构和每个观测的条件分布的规范形成的模型。从这样的MRF模型的快速模拟通常是一个重要的考虑因素,特别是当需要重复生成大量的数据集。然而,用于从MRF模型模拟的标准吉布斯策略涉及单站点更新,以顺序方式使用每个观测的条件单变量分布执行,由此即使对于中等样本,完整的吉布斯迭代也可能在计算上涉及。作为替代方案,我们描述了一种使用具有“concliques”的吉布斯抽样(即,非相邻观测的组)。与标准的吉布斯抽样相比,该模拟方案可以通过减少吉布斯步骤和独立地更新每个conclique的所有观测一次快得多。速度的提高取决于相对于用于模拟的样本量的浓缩物的数量,并且对于许多MRF模型(例如,具有适当有界的邻域)。我们详细的模拟方法,建立其有效性,并评估其计算性能,通过数值研究,速度优势,几个空间和网络的例子。

英文摘要:

For spatial and network data, we consider models formed from a Markov random field (MRF) structure and the specification of a conditional distribution for each observation. Fast simulation from such MRF models is often an important consideration, particularly when repeated generation of large numbers of data sets is required. However, a standard Gibbs strategy for simulating from MRF models involves single-site updates, performed with the conditional univariate distribution of each observation in a sequential manner, whereby a complete Gibbs iteration may become computationally involved even for moderate samples. As an alternative, we describe a general way to simulate from MRF models using Gibbs sampling with "concliques" (i.e., groups of non-neighboring observations). Compared to standard Gibbs sampling, this simulation scheme can be much faster by reducing Gibbs steps and independently updating all observations per conclique at once. The speed improvement depends on the number of concliques relative to the sample size for simulation, and order-of-magnitude speed increases are possible with many MRF models (e.g., having appropriately bounded neighborhoods). We detail the simulation method, establish its validity, and assess its computational performance through numerical studies, where speed advantages are shown for several spatial and network examples.

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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