Geometric No-U-Turn Samplers: Concepts and Evaluation

We enhance geometric Markov Chain Monte Carlo methods, in particular making them easier to use by providing better tools for choosing the metric and various tuning parameters. We extend the No-U-Turn criterion for automatic choice of integration length for Lagrangian Monte Carlo and propose a modification to the computationally efficient Monge metric, as well as summarizing several previously proposed metric choices. Through extensive experimentation, including synthetic examples and posteriordb benchmarks, we demonstrate that Riemannian metrics can outperform Euclidean counterparts, particularly in scenarios with high curvature, while highlighting how the optimal choice of metric is problem-specific.