The Gibbs Sampler is a general method for sampling high-dimensional distributions, dating back to 1971. In each step of the Gibbs Sampler, we pick a random coordinate and re-sample that coordinate from the distribution induced by fixing all the other coordinates. While it has become widely used over the past half-century, guarantees of efficient convergence have been elusive. We show that for a convex body K in ℝⁿ with diameter D, the mixing time of the Coordinate Hit-and-Run (CHAR) algorithm on K is polynomial in n and D. We also give a lower bound on the mixing rate of CHAR, showing that it is strictly worse than hit-and-run and the ball walk in the worst case.
@InProceedings{laddha_et_al:LIPIcs.SoCG.2021.51, author = {Laddha, Aditi and Vempala, Santosh S.}, title = {{Convergence of Gibbs Sampling: Coordinate Hit-And-Run Mixes Fast}}, booktitle = {37th International Symposium on Computational Geometry (SoCG 2021)}, pages = {51:1--51:12}, series = {Leibniz International Proceedings in Informatics (LIPIcs)}, ISBN = {978-3-95977-184-9}, ISSN = {1868-8969}, year = {2021}, volume = {189}, editor = {Buchin, Kevin and Colin de Verdi\`{e}re, \'{E}ric}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2021.51}, URN = {urn:nbn:de:0030-drops-138503}, doi = {10.4230/LIPIcs.SoCG.2021.51}, annote = {Keywords: Gibbs Sampler, Coordinate Hit and run, Mixing time of Markov Chain} }
Feedback for Dagstuhl Publishing