Hamiltonian Monte Carlo Inference of Marginalized Linear Mixed-Effects Models
This work addresses a computational bottleneck for researchers using Bayesian methods in fields like cognitive sciences, though it is incremental as it builds on existing Hamiltonian Monte Carlo techniques.
The paper tackled the challenge of inefficient Bayesian inference in linear mixed-effects models by developing an algorithm to automatically marginalize random effects, reducing computational time from cubic to linear and demonstrating benefits in models from cognitive sciences.
Bayesian reasoning in linear mixed-effects models (LMMs) is challenging and often requires advanced sampling techniques like Markov chain Monte Carlo (MCMC). A common approach is to write the model in a probabilistic programming language and then sample via Hamiltonian Monte Carlo (HMC). However, there are many ways a user can transform a model that make inference more or less efficient. In particular, marginalizing some variables can greatly improve inference but is difficult for users to do manually. We develop an algorithm to easily marginalize random effects in LMMs. A naive approach introduces cubic time operations within an inference algorithm like HMC, but we reduce the running time to linear using fast linear algebra techniques. We show that marginalization is always beneficial when applicable and highlight improvements in various models, especially ones from cognitive sciences.