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arXiv 0911.4546stat.MEstat.CO
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数据增强算法收敛性的改进及其在贝叶斯混合建模中的应用

Improving the Convergence Properties of the Data Augmentation Algorithm with an Application to Bayesian Mixture Modeling

James P. Hobert, Vivekananda Roy, Christian P. Robert

摘要:

驱动数据增强(DA)和三明治算法的可逆马尔可夫链定义了自伴算子,其谱编码算法的收敛特性。当目标分布有不可数的支持时,就像在实践中几乎总是这样,通常很难处理这些谱。我们证明了,如果增广空间是有限的,那么(在正则性条件下)由DA和三明治链定义的算子是紧的,并且谱是$[0,1)$的有限子集。证明了三明治算子的谱优于DA算子的谱,即三明治算子的序元素都小于或等于DA算子的序元素.作为一个具体的例子,我们研究了一个广泛使用的DA算法与贝叶斯混合模型相关的后验密度的探索[J.罗伊。中央集权主义者Soc.Ser.B56(1994)363 - 375]。特别是,我们比较了这种混合DA算法与Frühth-Schnatter [J. Amer. Statist. Assoc.96(2001)194 - 209],其基于随机标签交换。

英文摘要:

The reversible Markov chains that drive the data augmentation (DA) and sandwich algorithms define self-adjoint operators whose spectra encode the convergence properties of the algorithms. When the target distribution has uncountable support, as is nearly always the case in practice, it is generally quite difficult to get a handle on these spectra. We show that, if the augmentation space is finite, then (under regularity conditions) the operators defined by the DA and sandwich chains are compact, and the spectra are finite subsets of $[0,1)$. Moreover, we prove that the spectrum of the sandwich operator dominates the spectrum of the DA operator in the sense that the ordered elements of the former are all less than or equal to the corresponding elements of the latter. As a concrete example, we study a widely used DA algorithm for the exploration of posterior densities associated with Bayesian mixture models [J. Roy. Statist. Soc. Ser. B 56 (1994) 363--375]. In particular, we compare this mixture DA algorithm with an alternative algorithm proposed by Frühwirth-Schnatter [J. Amer. Statist. Assoc. 96 (2001) 194--209] that is based on random label switching.

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