Online Learning for Latent Dirichlet Allocation

This paper introduces a stochastic variational gradient based inference procedure for training Latent Dirichlet Allocation (LDA) models on very large text corpora. On the theoretical side it is shown that the training procedure converges to a local optimum and that, surprisingly, the simple stochastic gradient updates correspond to a stochastic natural gradient of the evidence lower bound (ELBO) objective. On the empirical side the authors show that for the first time LDA can be comfortably trained on text corpora of several hundreds of thousands of documents, making it a practical technique for “big data” problems. The idea has made a large impact in the ML community because it represented the first stepping stone for general stochastic gradient variational inference procedures for a much broader class of models. After this paper, there would be no good reason to ever use full batch training procedures for variational inference anymore.