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Covariance matrices are essential cosmological probes of fundamental physics, providing information on numerous fundamental physical parameters and varying with any change in the underlying cosmology. However, this cosmology dependence,…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-21 Theodore Steele , Robert Smith , Roisin O'Connor

Cosmological large-scale structure analyses based on two-point correlation functions often assume a Gaussian likelihood function with a fixed covariance matrix. We study the impact on cosmological parameter estimation of ignoring the…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-21 Darsh Kodwani , David Alonso , Pedro Ferreira

Covariance matrices are important tools for obtaining reliable parameter constraints. Advancements in cosmological surveys lead to larger data vectors and, consequently, increasingly complex covariance matrices, whose number of elements…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-31 Tassia Ferreira , Valerio Marra

Cosmological parameter estimation requires that the likelihood function of the data is accurately known. Assuming that cosmological large-scale structure power spectra data are multivariate Gaussian-distributed, we show the accuracy of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Andy Taylor , Benjamin Joachimi , Thomas Kitching

A prescription is presented for the interpolation between multi-dimensional distribution templates based on one or multiple model parameters. The technique uses a linear combination of templates, each created using fixed values of the…

Data Analysis, Statistics and Probability · Physics 2014-10-29 Max Baak , Stefan Gadatsch , Robert Harrington , Wouter Verkerke

When inferring parameters from a Gaussian-distributed data set by computing a likelihood, a covariance matrix is needed that describes the data errors and their correlations. If the covariance matrix is not known a priori, it may be…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 Elena Sellentin , Alan F. Heavens

We describe a statistical model to estimate the covariance matrix of matter tracer two-point correlation functions with cosmological simulations. Assuming a fixed number of cosmological simulation runs, we describe how to build a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Christopher B. Morrison , Michael D. Schneider

Data analysis in cosmology requires reliable covariance matrices. Covariance matrices derived from numerical simulations often require a very large number of realizations to be accurate. When a theoretical model for the covariance matrix…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-21 Alessandra Fumagalli , Matteo Biagetti , Alexandro Saro , Emiliano Sefusatti , Anže Slosar , Pierluigi Monaco , Alfonso Veropalumbo

In cosmic shear likelihood analyses the covariance is most commonly assumed to be constant in parameter space. Therefore, when calculating the covariance matrix (analytically or from simulations), its underlying cosmology should not…

Astrophysics · Physics 2015-05-13 Tim Eifler , Peter Schneider , Jan Hartlap

Covariance matrices of random vectors contain information that is crucial for modelling. Specific structures and patterns of the covariances (or correlations) may be used to justify parametric models, e.g., autoregressive models. Until now,…

Methodology · Statistics 2025-02-11 Paavo Sattler , Dennis Dobler

It has been proposed that complex populations, such as those that arise in genomics studies, may exhibit dependencies among observations as well as among variables. This gives rise to the challenging problem of analyzing unreplicated…

Machine Learning · Statistics 2018-06-08 Michael Hornstein , Roger Fan , Kerby Shedden , Shuheng Zhou

Estimating a covariance matrix is central to high-dimensional data analysis. Empirical analyses of high-dimensional biomedical data, including genomics, proteomics, microbiome, and neuroimaging, among others, consistently reveal strong…

Methodology · Statistics 2024-12-05 Yifan Yang , Chixiang Chen , Shuo Chen

In this study, we investigate the impact of covariance within uncertainties on the inference of cosmological and astrophysical parameters, specifically focusing on galaxy stellar mass functions derived from the CAMELS simulation suite.…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-30 Yongseok Jo , Shy Genel , Joel Leja , Benjamin Wandelt

We propose new concepts in order to analyze and model the dependence structure between two time series. Our methods rely exclusively on the order structure of the data points. Hence, the methods are stable under monotone transformations of…

Statistics Theory · Mathematics 2015-02-02 Alexander Schnurr , Herold Dehling

Physical theories that depend on many parameters or are tested against data from many different experiments pose unique challenges to statistical inference. Many models in particle physics, astrophysics and cosmology fall into one or both…

Testing covariance structure is of importance in many areas of statistical analysis, such as microarray analysis and signal processing. Conventional tests for finite-dimensional covariance cannot be applied to high-dimensional data in…

Statistics Theory · Mathematics 2013-10-31 Rongmao Zhang , Liang Peng , Ruodu Wang

The accurate computation of the covariance matrix of fitted model parameters is a somewhat neglected task in Statistics. Algorithms are given for computing accurate covariance matrices derived from computing the Hessian matrix by numerical…

Computation · Statistics 2021-05-12 Rose Baker

The statistical properties of estimator using covariance matrix for the account of point-to-point correlations due to systematic errors are analyzed. It is shown that the covariance matrix estimator (CME) is consistent for the realistic…

High Energy Physics - Experiment · Physics 2007-05-23 Alekhin Sergey

Statistical inference of the dependence between objects often relies on covariance matrices. Unless the number of features (e.g. data points) is much larger than the number of objects, covariance matrix cleaning is necessary to reduce…

Risk Management · Quantitative Finance 2021-06-09 Christian Bongiorno , Damien Challet

In this paper we focus on the solution of shifted quasiseparable systems and of more general parameter dependent matrix equations with quasiseparable representations. We propose an efficient algorithm exploiting the invariance of the…

Numerical Analysis · Mathematics 2017-08-07 Paola Boito , Yuli Eidelman , Luca Gemignani
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