Parallel Sampling of DP Mixture Models using Sub-Clusters Splits

We present an MCMC sampler for Dirichlet process mixture models that can be parallelized to achieve significant computational gains. We combine a nonergodic, restricted Gibbs iteration with split/merge proposals in a manner that produces an ergodic Markov chain. Each cluster is augmented with two subclusters to construct likely split moves. Unlike some previous parallel samplers, the proposed sampler enforces the correct stationary distribution of the Markov chain without the need for finite approximations. Empirical results illustrate that the new sampler exhibits better convergence properties than current methods.