UC Irvine

In this thesis we explore the problem of inference for Bayesian model averaging. Many popular topics in Bayesian analysis, such as Bayesian nonparametrics, can be cast as model averaging problems. Model averaging problems offer unique difficulties for inference, as the parameter space is not fixed, and may be infinite. As such, there is little existing work on general purpose MCMC algorithms in this area. We introduce a new MCMC sampler, which we call Retrospective Jump sampling, that is suitable for general purpose model averaging. In the development of Retrospective Jump, some practical issues arise in the need for a MCMC sampler for finite dimensions that is suitable for multimodal target densities; we introduce Refractive Sampling as a sampler suitable in this regard. Finally, we evaluate Retrospective Jump on several model averaging and Bayesian nonparametric problems, and develop a novel latent feature model with hierarchical column structure which uses Retrospective Jump for inference.