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Omar Chehab

5 accepted papers

2025

Density Ratio Estimation with Conditional Probability Paths

ICML 2025poster

Density ratio estimation in high dimensions can be reframed as integrating a certain quantity, the time score, over probability paths which interpolate between the two densities. In practice, the time score has to be estimated based on samples from the two densities. However, existing methods for th…

Cited by 0SourcePDFScholar
2025

Provable Convergence and Limitations of Geometric Tempering for Langevin Dynamics

ICLR 2025poster

Geometric tempering is a popular approach to sampling from challenging multi-modal probability distributions by instead sampling from a sequence of distributions which interpolate, using the geometric mean, between an easier proposal distribution and the target distribution. In this paper, we theore…

Cited by 3SourcePDFScholar
2025

Sampling from multi-modal distributions with polynomial query complexity in fixed dimension via reverse diffusion

NeurIPS 2025poster

Even in low dimensions, sampling from multi-modal distributions is challenging. We provide the first sampling algorithm for a broad class of distributions --- including all Gaussian mixtures --- with a query complexity that is polynomial in the parameters governing multi-modality, assuming fixed dim…

Cited by 0SourceScholar
2023

Provable benefits of annealing for estimating normalizing constants: Importance Sampling, Noise-Contrastive Estimation, and beyond

NeurIPS 2023spotlight

Recent research has developed several Monte Carlo methods for estimating the normalization constant (partition function) based on the idea of annealing. This means sampling successively from a path of distributions which interpolate between a tractable "proposal" distribution and the unnormalized "t…

2022

The optimal noise in noise-contrastive learning is not what you think

UAI 2022poster

Learning a parametric model of a data distribution is a well-known statistical problem that has seen renewed interest as it is brought to scale in deep learning. Framing the problem as a self-supervised task, where data samples are discriminated from noise samples, is at the core of state-of-the-art…

Cited by 19SourcePDFScholar