# What is the difference between SVI and online HDP algorithms?

I'm going over the paper by Hoffman et. al. titled "Stochastic Variational Inference" (SVI) where the authors present an algorithm for Hierarchical Dirichlet Process (HDP) topic models. I'm comparing this with a paper by Chong Wang et. al. titled "Online Variational Inference for the Hierarchical Dirichlet Process" where the authors present an online HDP algorithm (also implemented in gensim). And I'm wondering between the differences of these two algorithms. In what ways SVI HDP is different from online HDP?

This section is organized as follows. We first give some background on the Dirichlet process and its definition via Sethuraman’s stick breaking construction, which is a distribution on the infinite simplex. We then show how to use this construction to form the HDP topic model and how to use stochastic variational inference to approximate the posterior.$$^7$$