arXiv Statistics ML

MCMC Can See Can't See

arXiv Statistics ML
Oct 28

Learning on-the-fly quasi-stationarity diagnostics from low-dimensional surrogates

The paper introduces a new quasi‑stationarity diagnostic for accelerated dynamics methods, replacing traditional MCMC diagnostics with a coarse‑graining framework for killed Markov jump processes and a recurrent neural network trained on particle approximations of non‑linear effective flows. It provides uniform‑in‑time, non‑asymptotic bounds for approximating the true process’s probability flow without assuming reversibility, and demonstrates that the learned RNN diagnostic outperforms the MCMC approach in ROC analysis, is less conservative, fails less often, and offers an interpretable decision threshold.

By No\'e Blassel
arXiv Statistics ML
Aug 26

A Non-asymptotic Analysis for Learning and Applying a Preconditioner in MCMC

The paper presents a non‑asymptotic analysis of Markov chain Monte Carlo (MCMC) algorithms that learn and apply a preconditioner based on either the target covariance or the expected Hessian of the target potential. It compares the finite‑time computational costs of these preconditioned schemes with unpreconditioned counterparts, providing guarantees for algorithms such as the Unadjusted Langevin Algorithm (ULA) and the proximal sampler. The analysis relies on a contraction assumption in the Wasserstein‑2 distance to formalize approximate independence and bridge modern MCMC theory with classical effective sample size heuristics.

By Max Hird, Florian Maire, Jeffrey Negrea
arXiv Machine Learning
Jul 13

Global Sequential Testing for Multi-Stream Auditing

arXiv:2602. 21479v3 Announce Type: replace-cross Abstract: Across many risk-sensitive areas, it is critical to continuously audit machine learning systems as we receive more data to quickly determine if they are performing as designed.

By Beepul Bharti, Ambar Pal, Jeremias Sulam
arXiv Machine Learning
Sep 18

Next-token functional estimation

The paper introduces a leave‑a‑window‑out estimator for next‑token functionals, such as the surprise probability and test error, in sequences of random variables. By deleting a window of length τ after each index, the estimator generalizes leave‑one‑out and achieves parametric error decay for stationary β‑mixing processes that admit a Marton coupling. The authors provide both upper bounds and a minimax lower bound for the surprise probability, and demonstrate through simulations that their method outperforms traditional baselines on Markov, moving‑average, and autoregressive processes.

By Milind Nakul, Vidya Muthukumar, Ashwin Pananjady
arXiv Computer Vision
Sep 21

How Many Posterior Samples? Calibrated Stopping for Adaptive Sensing

The paper investigates how to decide when to stop collecting posterior samples in classification‑oriented adaptive sensing. It shows that a simple threshold‑based plug‑in rule does not guarantee the desired confidence level, and proposes calibrated fixed‑sample and finite‑horizon sequential stopping rules that control the false‑declaration probability. Experiments on MNIST demonstrate that the sequential rule can reduce sensing cost the most, and that a curtailment strategy can save up to 62% of posterior samples while maintaining accuracy.

By Vincent Corlay, Andriy Enttsel