arXiv Machine Learning

Amortised Inference through One-Step Implicit Sampling

The paper introduces OSIS, a one‑step implicit sampler that uses short‑time MCMC dynamics to define a local target for an implicitly modelled distribution. In the asymptotic limit, the model converges to a fixed point of the MCMC kernel, enabling unbiased sampling from the Bayesian posterior. Experiments show OSIS outperforms multi‑step amortised samplers and non‑amortised MCMC baselines while being far more efficient at sampling time.

arXiv Machine Learning
Aug 31

Improved off-policy training of diffusion samplers

The paper investigates training diffusion models to sample from distributions defined by unnormalized densities or energy functions. It benchmarks various diffusion-structured inference techniques, including simulation-based variational methods and off-policy approaches such as continuous generative flow networks, highlighting their relative strengths and challenging some prior claims. Additionally, the authors introduce a new exploration strategy for off-policy methods that employs local search in the target space with a replay buffer, demonstrating improved sample quality across multiple target distributions.

By Marcin Sendera, Minsu Kim, Sarthak Mittal, Pablo Lemos, Luca Scimeca, Jarrid Rector-Brooks, Alexandre Adam, Yoshua Bengio, Esmeralda S. Whitammer
arXiv AI
Jun 2

Efficient Weighted Sampling via Score-based Generative Models

arXiv:2502. 04646v2 Announce Type: replace-cross Abstract: Weighted sampling -- sampling from a probability density function (PDF) proportional to the product of a base PDF and a weight function -- is a fundamental technique with wide-ranging applications in variance reduction, biased sampling, data augmentation, and more.

By Heasung Kim, Taekyun Lee, Hyeji Kim, Gustavo de Veciana
arXiv Machine Learning
Sep 23

One-Step Generative Surrogate Models via Block-Triangular Joint Drifting

The paper introduces block‑triangular joint drifting, a method that applies a projected drift field to the joint distribution of consecutive states, enabling one‑step generative surrogate models for stochastic transition dynamics. This architecture preserves the current‑state marginal while directly sampling the conditional distribution of next states, allowing stochastic trajectories to be generated with a single model evaluation per time step. Experiments show that the approach achieves accurate marginal and trajectory‑dependent statistics with favorable accuracy‑cost tradeoffs compared to deterministic, diffusion, flow, and distillation‑based generative surrogates.

By Nicholas Geissler, Shreya Jha, Ricardo Baptista, Benjamin Peherstorfer
arXiv Statistics ML
Aug 28

A Two-step Metropolis Hastings Method for Bayesian Empirical Likelihood Computation with Application to Quantile Regression and Bayesian Model Selection

The paper introduces a two-step Metropolis–Hastings algorithm designed to efficiently sample from Bayesian empirical likelihood (BayesEL) posterior distributions, addressing challenges posed by the complex, often non‑convex support of empirical likelihood. The method leverages current parameter values and estimating equations to propose new values for remaining parameters, making it suitable for problems with discontinuous estimating equations such as simultaneous quantile regression. Additionally, the approach extends naturally to BayesEL model selection via reversible‑jump MCMC, and the authors demonstrate its utility through several real‑life applications.

By Sanjay Chaudhuri, Teng Yin, Snehashis Chakraborty, Rupsa Roy
arXiv AI
Jul 20

Energy-based Transport for Amortized Bayesian Inference

arXiv:2605. 15407v3 Announce Type: replace-cross Abstract: We consider amortized Bayesian inference for nonlinear inverse problems using only samples from the joint distribution of parameters and observations, including problems with unknown functions in a Banach space.

By Ricardo Baptista, Hojjat Kaveh, Andrew M. Stuart
arXiv Machine Learning
Oct 9

Bernoulli Flow Models: Self-Consistent Generative Modeling for Binary Data

Bernoulli Flow Models (BFM) introduce a continuous global Bernoulli probability flow path for binary data generation, replacing sequential one‑step Markov diffusion chains. By deriving analytical closed‑form posterior transitions over arbitrary time intervals, BFM eliminates the need for approximating multi‑step likelihoods and allows inference with far fewer function evaluations while maintaining sample quality. Experiments demonstrate that a BFM trained with 256 steps achieves an FID of 9.22 on LSUN Churches 256×256 using only 16 sampling steps, outperforming state‑of‑the‑art discrete baselines and remaining competitive under full‑step inference.

By Hao Mo, Liying Yang, Shumin Yao, Xinxing Yu, Ajian Liu, Xudong Mao, Yanyan Liang
arXiv Machine Learning
Jun 15

Implicit Variational Rejection Sampling

arXiv:2606. 14235v1 Announce Type: new Abstract: Variational Inference (VI) is a fundamental inference technique in Bayesian machine learning for approximating complex posterior distributions.

By Jian Xu, Shigui Li, Wei Chen, Jiacheng Li, Zhiqi Lin, Delu Zeng, Xinghao Ding, John Paisley, Qibin Zhao