Bayesian Parameter Estimation for Partially Observed McKean-Vlasov Diffusions Using Multilevel Markov chain Monte Carlo
Ajay Jasra, Amin Wu
TL;DR
The paper tackles Bayesian parameter estimation for partially observed McKean-Vlasov diffusions with discrete observations, where the posterior is intractable. It develops particle MCMC methods and extends them with multilevel MLMC to reduce computational cost, providing convergence bounds and demonstrating a cost reduction from $\mathcal{O}(\epsilon^{-7})$ to $\mathcal{O}(\epsilon^{-6})$ for attaining $\mathcal{O}(\epsilon^2)$ mean-squared error. The approach is validated on Kuramoto-type models, showing good mixing and substantial efficiency gains as the discretization level increases. This work enables scalable Bayesian inference for complex mean-field diffusion models and highlights the benefits of MLMC in PMCMC contexts.
Abstract
In this article we consider Bayesian estimation of static parameters for a class of partially observed McKean-Vlasov diffusion processes with discrete-time observations over a fixed time interval. This problem features several obstacles to its solution, which include that the posterior density is numerically intractable in continuous-time, even if the transition probabilities are available and even when one uses a time-discretization, the posterior still cannot be used by adopting well-known computational methods such as Markov chain Monte Carlo (MCMC). In this paper we provide a solution to this problem by using new MCMC algorithms which can solve the afore-mentioned issues. This MCMC algorithm is extended to use multilevel Monte Carlo (MLMC) methods. We prove convergence bounds on our parameter estimators and show that the MLMC-based MCMC algorithm reduces the computational cost to achieve a mean square error versus ordinary MCMC by an order of magnitude. We numerically illustrate our results on two models.
