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arXiv 2107.07313stat.ME
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出租车采样器:离散空间的MCMC及其在树模型中的应用

The Taxicab Sampler: MCMC for Discrete Spaces with Application to Tree Models

Vincent Geels, Matthew Pratola, Radu Herbei

摘要:

针对贝叶斯模型中离散但非常复杂的状态空间问题,提出了一种新的马尔可夫链蒙特卡罗搜索算法:出租车采样器。我们描述了这个采样器的建设,并讨论了它的解释和使用不同的标准大都会黑斯廷斯以及相关的汉明球采样器。所提出的抽样算法,然后证明在计算时间没有任何损失的效率相对于一个天真的大都会黑斯廷斯搜索在一个激励贝叶斯回归树计数模型的实质性改善,其中,我们利用离散状态空间假设来构造新的似然函数,该函数允许灵活地描述不同的均值,方差关系,同时与计数数据的现有似然函数相比保持参数可解释性。

英文摘要:

Motivated by the problem of exploring discrete but very complex state spaces in Bayesian models, we propose a novel Markov Chain Monte Carlo search algorithm: the taxicab sampler. We describe the construction of this sampler and discuss how its interpretation and usage differs from that of standard Metropolis-Hastings as well as the related Hamming ball sampler. The proposed sampling algorithm is then shown to demonstrate substantial improvement in computation time without any loss of efficiency relative to a naïve Metropolis-Hastings search in a motivating Bayesian regression tree count model, in which we leverage the discrete state space assumption to construct a novel likelihood function that allows for flexibly describing different mean-variance relationships while preserving parameter interpretability compared to existing likelihood functions for count data.

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