Biometrika Mar 31, 2026

Parallel computations for Metropolis Markov chains with Picard maps

Authors
G Zanella S Grazzi
Research Topics
Machine Learning Bayesian Statistics
Paper Information
  • Journal:
    Biometrika
  • DOI:
    10.1093/biomet/asag022
  • Published:
    March 31, 2026
  • Added to Tracker:
    Apr 02, 2026
Abstract

Abstract We develop parallel algorithms for simulating zeroth-order (also known as gradient-free) Metropolis Markov chains based on the Picard map. For random-walk Metropolis Markov chains targeting log-concave distributions π on ℝd, our algorithm generates samples close to π in O(d) parallel iterations using O(d) processors, thereby speeding up the convergence of the corresponding sequential implementation by a factor (d). Furthermore, a modification of our algorithm generates samples from an approximate measure πr in O(1) parallel iterations and O(d) processors. We empirically assess the performance of the proposed algorithms in high-dimensional regression problems, an epidemic model where the gradient is unavailable and a real-word application in precision medicine. Our algorithms are straightforward to implement and may constitute a useful tool for practitioners seeking to sample from a prescribed distribution π using only pointwise evaluations of π and parallel computing.

Author Details
G Zanella
Author
S Grazzi
Author
Research Topics & Keywords
Machine Learning
Research Area
Bayesian Statistics
Research Area
Citation Information
APA Format
G Zanella & S Grazzi (2026) . Parallel computations for Metropolis Markov chains with Picard maps. Biometrika , 10.1093/biomet/asag022.
BibTeX Format
@article{paper1102,
  title = { Parallel computations for Metropolis Markov chains with Picard maps },
  author = { G Zanella and S Grazzi },
  journal = { Biometrika },
  year = { 2026 },
  doi = { 10.1093/biomet/asag022 },
  url = { https://doi.org/10.1093/biomet/asag022 }
}