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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

The method of stable random projections is a tool for efficiently computing the $l_\alpha$ distances using low memory, where $0<\alpha \leq 2$ is a tuning parameter. The method boils down to a statistical estimation task and various…

Machine Learning · Computer Science 2008-12-18 Ping Li

We consider sample covariance matrices $S_N=\frac{1}{p}\Sigma_N^{1/2}X_NX_N^* \Sigma_N^{1/2}$ where $X_N$ is a $N \times p$ real or complex matrix with i.i.d. entries with finite $12^{\rm th}$ moment and $\Sigma_N$ is a $N \times N$…

Probability · Mathematics 2009-11-17 Olivier Ledoit , Sandrine Péché

Covariance matrices play a major role in statistics, signal processing and machine learning applications. This paper focuses on the \textit{semiparametric} covariance/scatter matrix estimation problem in elliptical distributions. The class…

Signal Processing · Electrical Eng. & Systems 2020-10-28 Stefano Fortunati , Alexandre Renaux , Frédéric Pascal

This paper addresses the task of estimating a covariance matrix under a patternless sparsity assumption. In contrast to existing approaches based on thresholding or shrinkage penalties, we propose a likelihood-based method that regularizes…

Methodology · Statistics 2021-09-13 Jason Xu , Kenneth Lange

The family of rank estimators, including Han's maximum rank correlation (Han, 1987) as a notable example, has been widely exploited in studying regression problems. For these estimators, although the linear index is introduced for…

Statistics Theory · Mathematics 2019-08-15 Yanqin Fan , Fang Han , Wei Li , Xiao-Hua Zhou

Randomized matrix algorithms have become workhorse tools in scientific computing and machine learning. To use these algorithms safely in applications, they should be coupled with posterior error estimates to assess the quality of the…

Numerical Analysis · Mathematics 2024-10-03 Ethan N. Epperly , Joel A. Tropp

In this paper, we present several estimators of the diagonal elements of the inverse of the covariance matrix, called precision matrix, of a sample of iid random vectors. The focus is on high dimensional vectors having a sparse precision…

Statistics Theory · Mathematics 2017-07-31 Samuel Balmand , Arnak S. Dalalyan

Suppose that $X_1,X_2,\ldots$ are a stream of independent, identically distributed Poisson random variables with mean $\mu$. This work presents a new estimate $\mu_k$ for $\mu$ with the property that the distribution of the relative error…

Computation · Statistics 2016-06-01 Mark Huber

We propose a new pivotal method for estimating high-dimensional matrices. Assume that we observe a small set of entries or linear combinations of entries of an unknown matrix $A\_0$ corrupted by noise. We propose a new method for estimating…

Statistics Theory · Mathematics 2015-02-03 Olga Klopp , Stéphane Gaiffas

The performance of known and new parametric estimators for Archimedean copulas is investigated, with special focus on large dimensions and numerical difficulties. In particular, method-of-moments-like estimators based on pairwise Kendall's…

Computation · Statistics 2012-11-05 Marius Hofert , Martin Maechler , Alexander J. McNeil

Compositional data arise in many areas of research in the natural and biomedical sciences. One prominent example is in the study of the human gut microbiome, where one can measure the relative abundance of many distinct microorganisms in a…

Methodology · Statistics 2024-04-26 Aaron J. Molstad , Karl Oskar Ekvall , Piotr M. Suder

This paper proposes a family of weighted batch means variance estimators, which are computationally efficient and can be conveniently applied in practice. The focus is on Markov chain Monte Carlo simulations and estimation of the asymptotic…

Statistics Theory · Mathematics 2018-05-23 Ying Liu , James M. Flegal

Computing the inverse covariance matrix (or precision matrix) of large data vectors is crucial in weak lensing (and multi-probe) analyses of the large scale structure of the universe. Analytically computed covariances are noise-free and…

Instrumentation and Methods for Astrophysics · Physics 2017-12-06 Oliver Friedrich , Tim Eifler

We study the problem of estimating the covariance matrix of a high-dimensional distribution when a small constant fraction of the samples can be arbitrarily corrupted. Recent work gave the first polynomial time algorithms for this problem…

Machine Learning · Computer Science 2019-06-12 Yu Cheng , Ilias Diakonikolas , Rong Ge , David Woodruff

In this study, a longitudinal regression model for covariance matrix outcomes is introduced. The proposal considers a multilevel generalized linear model for regressing covariance matrices on (time-varying) predictors. This model…

Methodology · Statistics 2022-02-10 Yi Zhao , Brian S. Caffo , Xi Luo

Estimation of covariance matrices or their inverses plays a central role in many statistical methods. For these methods to work reliably, estimated matrices must not only be invertible but also well-conditioned. In this paper we present an…

Methodology · Statistics 2014-08-06 Eric C. Chi , Kenneth Lange

In this paper a new fast algorithm for the computation of the distance of a matrix to a nearby defective matrix is presented. The problem is formulated following Alam & Bora (Linear Algebra Appl., 396 (2005), pp.~273--301) and reduces to…

Numerical Analysis · Mathematics 2012-11-05 Melina A. Freitag , Alastair Spence

Motivated by the Bures distance, we introduce a new family of distances, \emph{relative translation invariant Wasserstein distances}, denoted by $RW_p$, as an extension of the classical Wasserstein distances $W_p$ for $p \in [1, +\infty)$.…

Machine Learning · Computer Science 2026-05-26 Binshuai Wang , Qiwei Di , Ming Yin , Mengdi Wang , Quanquan Gu , Peng Wei

This paper is on the normal approximation of singular subspaces when the noise matrix has i.i.d. entries. Our contributions are three-fold. First, we derive an explicit representation formula of the empirical spectral projectors. The…

Statistics Theory · Mathematics 2019-07-29 Dong Xia