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Randomized sketching accelerates large-scale numerical linear algebra by reducing computational complexity. While the traditional sketch-and-solve approach reduces the problem size directly through sketching, the sketch-and-precondition…

Numerical Analysis · Mathematics 2025-05-23 Ruihan Xu , Yiping Lu

Estimating large covariance matrices has been a longstanding important problem in many applications and has attracted increased attention over several decades. This paper deals with two methods based on pre-existing works to impose sparsity…

Applications · Statistics 2017-12-06 Ahmad W. Bitar , Jean-Philippe Ovarlez , Loong-Fah Cheong

We propose a general procedure for estimating the variance-covariance matrix of two-step estimates of structural parameters in latent variable models. The method is partially simulation-based, in that it includes drawing simulated values of…

Methodology · Statistics 2025-07-23 Roberto Di Mari , Jouni Kuha

We study the estimation of the covariance matrix $\Sigma$ of a $p$-dimensional normal random vector based on $n$ independent observations corrupted by additive noise. Only a general nonparametric assumption is imposed on the distribution of…

Statistics Theory · Mathematics 2018-03-28 Denis Belomestny , Mathias Trabs , Alexandre B. Tsybakov

Randomized linear system solvers have become popular as they have the potential to reduce floating point complexity while still achieving desirable convergence rates. One particularly promising class of methods, random sketching solvers,…

Numerical Analysis · Mathematics 2020-12-23 Vivak Patel , Mohammad Jahangoshahi , Daniel Adrian Maldonado

We consider the problem of constructing a reduced-rank regression model whose coefficient parameter is represented as a singular value decomposition with sparse singular vectors. The traditional estimation procedure for the coefficient…

Machine Learning · Statistics 2019-11-04 Kohei Yoshikawa , Shuichi Kawano

How can we discern whether the covariance operator of a stochastic process is of reduced rank, and if so, what its precise rank is? And how can we do so at a given level of confidence? This question is central to a great deal of methods for…

Methodology · Statistics 2020-08-11 Anirvan Chakraborty , Victor M. Panaretos

This paper introduces a subspace method for the estimation of an array covariance matrix. It is shown that when the received signals are uncorrelated, the true array covariance matrices lie in a specific subspace whose dimension is…

Numerical Analysis · Computer Science 2014-11-04 Mostafa Rahmani , George Atia

Merge trees are a type of topological descriptors that record the connectivity among the sublevel sets of scalar fields. They are among the most widely used topological tools in visualization. In this paper, we are interested in sketching a…

Computational Geometry · Computer Science 2021-06-01 Mingzhe Li , Sourabh Palande , Lin Yan , Bei Wang

We study the problem of multivariate regression where the data are naturally grouped, and a regression matrix is to be estimated for each group. We propose an approach in which a dictionary of low rank parameter matrices is estimated across…

Machine Learning · Computer Science 2012-07-03 Min Xu , John Lafferty

Sketching has emerged as a powerful technique for speeding up problems in numerical linear algebra, such as regression. In the overconstrained regression problem, one is given an $n \times d$ matrix $A$, with $n \gg d$, as well as an $n…

Data Structures and Algorithms · Computer Science 2017-05-31 Eric Price , Zhao Song , David P. Woodruff

Accounting for the uncertainty in the predictions of modern neural networks is a challenging and important task in many domains. Existing algorithms for uncertainty estimation require modifying the model architecture and training procedure…

Machine Learning · Statistics 2022-05-09 Alexander Fishkov , Maxim Panov

We study covariance matrix estimation for the case of partially observed random vectors, where different samples contain different subsets of vector coordinates. Each observation is the product of the variable of interest with a $0-1$…

Machine Learning · Statistics 2018-04-06 Eduardo Pavez , Antonio Ortega

We present a method for estimating sparse high-dimensional inverse covariance and partial correlation matrices, which exploits the connection between the inverse covariance matrix and linear regression. The method is a two-stage estimation…

Machine Learning · Statistics 2025-05-13 Samuel Erickson , Tobias Rydén

Sketches, with their expressive potential, allow humans to convey the essence of an object through even a rough contour. For the first time, we harness this expressive potential to improve segmentation performance in challenging tasks like…

Computer Vision and Pattern Recognition · Computer Science 2025-02-03 Ying Zang , Runlong Cao , Jianqi Zhang , Yidong Han , Ziyue Cao , Wenjun Hu , Didi Zhu , Lanyun Zhu , Zejian Li , Deyi Ji , Tianrun Chen

We consider the problem of covariance matrix estimation in the presence of latent variables. Under suitable conditions, it is possible to learn the marginal covariance matrix of the observed variables via a tractable convex program, where…

Machine Learning · Statistics 2011-10-17 Gui-Bo Ye , Yuanfeng Wang , Yifei Chen , Xiaohui Xie

We propose iterative projection methods for solving square or rectangular consistent linear systems Ax = b. Existing projection methods use sketching matrices (possibly randomized) to generate a sequence of small projected subproblems, but…

Numerical Analysis · Mathematics 2023-12-13 Johannes J. Brust , Michael A. Saunders

This paper concerns a fundamental class of convex matrix optimization problems. It presents the first algorithm that uses optimal storage and provably computes a low-rank approximation of a solution. In particular, when all solutions have…

Optimization and Control · Mathematics 2017-02-23 Alp Yurtsever , Madeleine Udell , Joel A. Tropp , Volkan Cevher

Power iteration can improve the accuracy of randomized SVD, but requires multiple data passes, making it impractical in streaming or memory-constrained settings. We introduce a lightweight yet effective sketch-power iteration, allowing…

Numerical Analysis · Mathematics 2026-03-30 Chao Chang , Yuning Yang

We introduce a novel Bayesian approach for both covariate selection and sparse precision matrix estimation in the context of high-dimensional Gaussian graphical models involving multiple responses. Our approach provides a sparse estimation…

Methodology · Statistics 2024-09-25 Anwesha Chakravarti , Naveen N. Narishetty , Feng Liang
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