Designing alternative proposal chains with improved mixing

Develop alternative proposal Markov chains for Metropolis-adjusted constrained sampling that achieve similar or better mixing-time guarantees than MAPLA, and quantify their dependence on dimension and metric properties.

Background

MAPLA uses a natural-gradient-inspired proposal; the authors highlight the open question of whether other proposals might yield superior one-step overlap or acceptance properties and thus improved mixing times, especially under self-concordant or stronger metric assumptions.

Such designs could lead to new first-order samplers that are more efficient or robust across diverse constrained domains, complementing MAPLA and DikinWalk.

References

Several open questions remain. Algorithmically, it would be also be interesting to find other candidate proposal Markov chains that can yield similar or better mixing time guarantees.

High-accuracy sampling from constrained spaces with the Metropolis-adjusted Preconditioned Langevin Algorithm (2412.18701 - Srinivasan et al., 24 Dec 2024) in Section 7 (Conclusion), final paragraph