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A Unified Particle-Optimization Framework for Scalable Bayesian Sampling
Proceedings of the 34th Conference on Uncertainty in Artificial Intelligence, PMLR R16:745-754, 2018.
Abstract
There has been recent interest in developing scalable Bayesian sampling methods such as stochastic gradient MCMC (SG-MCMC) and Stein variational gradient descent (SVGD) for big-data analysis. A standard SG-MCMC algo- rithm simulates samples from a discrete-time Markov chain to approximate a target distribu- tion, thus samples could be highly correlated, an undesired property for SG-MCMC. In con- trary, SVGD directly optimizes a set of particles to approximate a target distribution, and thus is able to obtain good approximations with rela- tively much fewer samples. In this paper, we propose a principle particle-optimization frame- work based on Wasserstein gradient flows to unify SG-MCMC and SVGD, and to allow new algorithms to be developed. Our framework interprets SG-MCMC as particle optimization on the space of probability measures, revealing a strong connection between SG-MCMC and SVGD. The key component of our framework is several particle-approximate techniques to efficiently solve the original partial differential equations on the space of probability measures. Extensive experiments on both synthetic data and deep neural networks demonstrate the ef- fectiveness and efficiency of our framework for scalable Bayesian sampling.