arXiv Statistics ML

Seeing the Forest for the Trees: The Gaussian Process Limit of BART

arXiv Machine Learning
Sep 24

Dirichlet Process Mixtures of Trees with Gaussian Process Splits: A Bayesian Nonparametric Framework with Posterior Contraction Rate

arXiv:2609. 27930v1 Announce Type: cross Abstract: We propose a Bayesian nonparametric mixture of regression trees with a Dirichlet process prior over tree-parameter pairs, enabling data-driven selection of ensemble size and unifying CART, BART, random forests, and boosting.

By Subhasish Basak, Anik Roy, Sourabh Bhattacharya
arXiv Machine Learning
Aug 27

Fast rates in Bayesian online learning with approximate posteriors

The paper investigates how fast predictive regret guarantees of exact Bayesian online learning can be maintained when using approximate posterior methods. It establishes a general theorem linking the cumulative cost of posterior approximation to the contraction radius of the exact Gibbs posterior and the Wasserstein distance between approximate and exact posteriors. Three concrete online learning scenarios—linear models, infinite‑dimensional exponential families, and Gaussian process regression—illustrate that appropriately accurate approximations (projected Langevin, truncation, and sparse variational posteriors) preserve fast regret bounds while reducing computational demands.

By Ilsang Ohn
arXiv Statistics ML
Oct 5

A Residual Tree Gaussian Process Modeling Framework for High-Dimensional Data

The paper introduces ResTGP, a Bayesian residual tree Gaussian Process framework designed for large, high‑dimensional spatial datasets with heterogeneous structures. It decomposes a Gaussian process across a dyadic tree, iteratively computing predictive and residual processes at each node to capture multi‑scale covariance efficiently. The method employs recursive message passing for linear‑time Bayesian inference and demonstrates posterior consistency, with numerical experiments and a storm surge application highlighting its advantages.

By Pulong Ma, Li Ma
arXiv Machine Learning
Aug 28

Gaussian Processes and Reproducing Kernel Hilbert Spaces: Connections and Equivalences

The monograph explores the relationships between Gaussian processes and reproducing kernel Hilbert spaces (RKHS), two widely used approaches that rely on positive definite kernels. It examines how these frameworks connect and are equivalent across key topics such as regression, interpolation, numerical integration, distributional discrepancies, statistical dependence, and Gaussian process sample path properties. By establishing a unifying perspective based on the equivalence between the Gaussian Hilbert space and the RKHS, the work aims to bridge methods developed independently by the machine learning, statistics, and numerical analysis communities.

By Motonobu Kanagawa, Philipp Hennig, Dino Sejdinovic, Bharath K. Sriperumbudur
arXiv Machine Learning
Oct 23

The Fenchel-Young Generalization of Bayesian Principles

The paper extends the classical conjugate Bayesian framework by leveraging the Fenchel‑Young inequality to define a generalized evidence lower bound that transcends the usual KL geometry. This leads to a new notion of conjugacy—closure of prior‑potential families that remain affine under loss translation—allowing additive canonical updates, parameter‑dependent support, and tunable heavy‑tailed posteriors. The authors also derive a Fenchel‑Young generalization of EM, encompassing both classical and hard EM, and demonstrate its utility in generalized Bayesian linear regression and sparse Gaussian mixture models.

By Sophia Sklaviadis, Thomas Moellenhoff, Emtiyaz Khan, Andre Martins, Mario Figueiredo
arXiv Machine Learning
Oct 8

Scalable Logistic Gaussian Process Density Regression with Kinetic Langevin Sampling

The paper introduces a scalable Bayesian method for conditional density estimation using a logistic Gaussian process. It models the log conditional density with a separable covariance— a Matérn kernel on the response dimension and a Nyström-feature kernel on covariates— and samples the latent field via kinetic Langevin dynamics instead of traditional approximations. Experiments on photometric‑redshift data with up to 3.9 million observations show the approach matches state‑of‑the‑art tabular foundation models on density and calibration metrics.

By Daniel Paulin, \'Ad\'am Jung, Andr\'as A. Bencz\'ur