Explicit convergence bounds for Metropolis Markov chains: isoperimetry, spectral gaps and profiles

Autor: Andrieu, Christophe, Lee, Anthony, Power, Sam, Wang, Andi Q.
Rok vydání: 2022
Předmět:
Zdroj: Ann. Appl. Probab. 34(4): 4022-4071 (August 2024)
Druh dokumentu: Working Paper
DOI: 10.1214/24-AAP2058
Popis: We derive the first explicit bounds for the spectral gap of a random walk Metropolis algorithm on $R^d$ for any value of the proposal variance, which when scaled appropriately recovers the correct $d^{-1}$ dependence on dimension for suitably regular invariant distributions. We also obtain explicit bounds on the ${\rm L}^2$-mixing time for a broad class of models. In obtaining these results, we refine the use of isoperimetric profile inequalities to obtain conductance profile bounds, which also enable the derivation of explicit bounds in a much broader class of models. We also obtain similar results for the preconditioned Crank--Nicolson Markov chain, obtaining dimension-independent bounds under suitable assumptions.
Databáze: arXiv