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Efficient schemes for sampling from the eigenvalues of the Wishart distribution have recently been described for both the uncorrelated central case (where the covariance matrix is $\mathbf{I}$) and the spiked Wishart with a single spike…

Computation · Statistics 2024-10-10 Thomas G. Brooks

We are interested in the distribution of Wishart samples after forgetting their scaling factors. We call such a distribution a projective Wishart distribution. We show that projective Wishart distributions have strong links with the…

Statistics Theory · Mathematics 2024-07-16 Emmanuel Chevallier

Distribution shift poses a significant challenge in machine learning, particularly in biomedical applications using data collected across different subjects, institutions, and recording devices, such as sleep data. While existing…

Machine Learning · Computer Science 2026-02-02 Théo Gnassounou , Antoine Collas , Rémi Flamary , Alexandre Gramfort

This paper deals with Elliptical Wishart distributions - which generalize the Wishart distribution - in the context of signal processing and machine learning. Two algorithms to compute the maximum likelihood estimator (MLE) are proposed: a…

Machine Learning · Statistics 2024-11-06 Imen Ayadi , Florent Bouchard , Frédéric Pascal

The Wishart distribution and its generalizations are among the most prominent probability distributions in multivariate statistical analysis, arising naturally in applied research and as a basis for theoretical models. In this paper, we…

Statistics Theory · Mathematics 2015-02-26 A. Bekker , M. Arashi , J. van Niekerk

Analysis of structural and functional connectivity (FC) of human brains is of pivotal importance for diagnosis of cognitive ability. The Human Connectome Project (HCP) provides an excellent source of neural data across different regions of…

Applications · Statistics 2020-07-10 Satwik Acharyya , Zhengwu Zhang , Anirban Bhattacharya , Debdeep Pati

Diffusion models are increasingly being utilised to create synthetic tabular and time series data for privacy-preserving augmentation. Tabular Denoising Diffusion Probabilistic Models (TabDDPM) generate high-quality synthetic data from…

Machine Learning · Computer Science 2026-04-08 Umang Dobhal , Christina Garcia , Sozo Inoue

Linear Discriminant Analysis (LDA) on Electronic Health Records (EHR) data is widely-used for early detection of diseases. Classical LDA for EHR data classification, however, suffers from two handicaps: the ill-posed estimation of LDA…

Machine Learning · Computer Science 2017-04-26 Haoyi Xiong , Wei Cheng , Wenqing Hu , Jiang Bian , Zhishan Guo

This paper focuses on the non-asymptotic concentration of the heteroskedastic Wishart-type matrices. Suppose $Z$ is a $p_1$-by-$p_2$ random matrix and $Z_{ij} \sim N(0,\sigma_{ij}^2)$ independently, we prove the expected spectral norm of…

Statistics Theory · Mathematics 2022-02-17 T. Tony Cai , Rungang Han , Anru R. Zhang

We develop a nonparametric two-sample test for distributions supported on the cone of symmetric positive definite matrices. The procedure relies on the Wishart kernel density estimator (KDE) introduced by Belzile et al. (2025), whose…

Statistics Theory · Mathematics 2026-03-17 Frédéric Ouimet

Complex systems are typically represented by large ensembles of observations. Correlation matrices provide an efficient formal framework to extract information from such multivariate ensembles and identify in a quantifiable way patterns of…

Data Analysis, Statistics and Probability · Physics 2011-06-03 Stanislaw Drozdz , Jaroslaw Kwapien , Andreas A. Ioannides

In medicine, curated image datasets often employ discrete labels to describe what is known to be a continuous spectrum of healthy to pathological conditions, such as e.g. the Alzheimer's Disease Continuum or other areas where the image…

Computer Vision and Pattern Recognition · Computer Science 2022-09-27 Matteo Ferrante , Tommaso Boccato , Simeon Spasov , Andrea Duggento , Nicola Toschi

Covariance matrix estimation arises in multivariate problems including multivariate normal sampling models and regression models where random effects are jointly modeled, e.g. random-intercept, random-slope models. A Bayesian analysis of…

Methodology · Statistics 2016-07-14 Ignacio Alvarez , Jarad Niemi , Matt Simpson

In this paper, we derive the explicit series expansion of the eigenvalue distribution of various models, namely the case of non-central Wishart distributions, as well as correlated zero mean Wishart distributions. The tools used extend…

Information Theory · Computer Science 2016-11-17 Ø. Ryan , A. Masucci , S. Yang , M. Debbah

The scaled complex Wishart distribution is a widely used model for multilook full polarimetric SAR data whose adequacy has been attested in the literature. Classification, segmentation, and image analysis techniques which depend on this…

Machine Learning · Statistics 2023-07-19 Alejandro C. Frery , Abraão D. C. Nascimento , Renato J. Cintra

Data represented as covariance-type matrices arise in many fields, including brain functional connectivity and diffusion tensor imaging. We develop the MFM-Wishart, a Bayesian model-based clustering approach for such data that combines…

Methodology · Statistics 2026-05-25 Zongyu Li , Stefano Castruccio , Zhiyong Zhang

Weakly Supervised Anomaly detection (WSAD) in brain MRI scans is an important challenge useful to obtain quick and accurate detection of brain anomalies when precise pixel-level anomaly annotations are unavailable and only weak labels…

Computer Vision and Pattern Recognition · Computer Science 2026-04-09 Bheeshm Sharma , Karthikeyan Jaganathan , Balamurugan Palaniappan

In this work, we consider the weighted difference of two independent complex Wishart matrices and derive the joint probability density function of the corresponding eigenvalues in a finite-dimension scenario using two distinct approaches.…

Mathematical Physics · Physics 2020-11-17 Santosh Kumar , S. Sai Charan

We present a Bayesian non-parametric way of inferring stochastic differential equations for both regression tasks and continuous-time dynamical modelling. The work has high emphasis on the stochastic part of the differential equation, also…

Machine Learning · Statistics 2020-06-29 Martin Jørgensen , Marc Peter Deisenroth , Hugh Salimbeni

Autism Spectrum Disorder is a condition characterized by a typical brain development leading to impairments in social skills, communication abilities, repetitive behaviors, and sensory processing. There have been many studies combining…

Image and Video Processing · Electrical Eng. & Systems 2024-05-28 Junlin Song , Yuzhuo Chen , Yuan Yao , Zetong Chen , Renhao Guo , Lida Yang , Xinyi Sui , Qihang Wang , Xijiao Li , Aihua Cao , Wei Li