arXiv Machine Learning

The Tractability Landscape of Sampling with Inexact Scores

arXiv:2607. 19004v1 Announce Type: cross Abstract: We provide a simple and tight characterization of the types of inexact score oracle access that permit sampling with vanishing total variation bias, for a standard, well-behaved target family.

arXiv Machine Learning
Nov 5

Uniform Race: Parameter-Free Approximate Rejection Sampling

The paper introduces Uniform Race (UR), a parameter‑free algorithm for approximate rejection sampling that selects a sample by maximizing the ratio of its importance weight to an independent uniform random variable. UR achieves the same total variation error bound as the optimal rejection sampler that requires knowledge of the best acceptance threshold, and it outperforms both the budget‑calibrated rejection sampler and sampling importance resampling in certain settings. The authors also provide theoretical conditions under which UR’s selection probabilities are uniquely optimal and validate the method on large‑language‑model reasoning tasks.

By Seiyun Shin, Juhyeong Pang, Kwang-Sung Jun
arXiv Machine Learning
Aug 7

Beyond Marginal Validity: Finite-Sample Guarantees for Localized Conformal Prediction

arXiv:2608. 06206v1 Announce Type: cross Abstract: Conformal prediction endows arbitrary black-box predictors with finite-sample, distribution-free marginal coverage, yet marginal validity can hide severe covariate-specific miscalibration, while exact distribution-free conditional coverage is finite-sample unattainable.

By Anton Conrad, Rustam Isaev, Denis Belomestny, Eric Moulines, Sergey Samsonov
arXiv AI
Sep 24

Ask Which, Not How Good: Sizing Benchmarks Scored by an LLM

The study analyzes 373,019 judgments from LLM‑scored benchmarks, decomposing variance into system, item, judge, and interaction components via generalizability theory. It finds that with a single judge, generalizability converges to a ceiling determined by the system‑by‑judge variance, which is substantially lower in pairwise preference settings, allowing one judge to suffice. The research also reveals significant biases in presentation order and highlights that many published win‑rate claims fall below the measured floor of the benchmarks.

By Atul Anand
arXiv AI
Jun 11

The Power of Test-Time Training for Approximate Sampling

arXiv:2606. 11437v1 Announce Type: cross Abstract: Efficiently sampling from a complex probability distribution is a fundamental problem which has become increasingly pertinent in recent years with the rise of generative AI, as sophisticated sampling procedures from LLMs have been proposed to solve challenging reasoning problems.

By Noah Golowich, Ankur Moitra, Dhruv Rohatgi
arXiv Machine Learning
Oct 8

Lower Bounds for Parallel Diffusion Sampling

The paper establishes the first polynomial lower bounds on the number of parallel rounds required for diffusion sampling with approximate scores. It proves a “~Ω(d^{1/3})” lower bound for sampling smooth, near‑isotropic Gaussian mixtures in ℝ^d, and an Ω(d) lower bound for uniform sampling from anisotropic axis‑aligned boxes inside the unit ball. These bounds apply to any randomized algorithm that can make polynomially many queries per round at arbitrary locations and noise levels, while maintaining inverse‑polynomial score error and constant total variation accuracy.

By Yiwen Kou, Yimeng Wang