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Many inverse problems in nuclear fusion and high-energy astrophysics research, such as the optimization of tokamak reactor geometries or the inference of black hole parameters from interferometric images, necessitate high-dimensional…

机器学习 · 计算机科学 2025-05-09 Jonathan Gorard , Ammar Hakim , Hong Qin , Kyle Parfrey , Shantenu Jha

Traditional Markov Chain Monte Carlo methods suffer from low acceptance rate, slow mixing and low efficiency in high dimensions. Hamiltonian Monte Carlo resolves this issue by avoiding the random walk. Hamiltonian Monte Carlo (HMC) is a…

天体物理学 · 物理学 2008-11-26 Amir Hajian

We quantify the information content of the non-linear matter power spectrum, the halo mass function, and the void size function, using the Quijote $N$-body simulations. We find that these three statistics exhibit very different degeneracies…

This paper deals with the time-varying high dimensional covariance matrix estimation. We propose two covariance matrix estimators corresponding with a time-varying approximate factor model and a time-varying approximate characteristic-based…

计量经济学 · 经济学 2019-10-29 Jaeheon Jung

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…

统计理论 · 数学 2013-10-31 Rongmao Zhang , Liang Peng , Ruodu Wang

We propose new methods for multivariate linear regression when the regression coefficient matrix is sparse and the error covariance matrix is dense. We assume that the error covariance matrix has equicorrelation across the response…

统计方法学 · 统计学 2025-08-13 Daeyoung Ham , Bradley S. Price , Adam J. Rothman

This paper studies the problem of estimating the covariance of a collection of vectors using only highly compressed measurements of each vector. An estimator based on back-projections of these compressive samples is proposed and analyzed. A…

机器学习 · 统计学 2019-01-16 Martin Azizyan , Akshay Krishnamurthy , Aarti Singh

Super-sample covariance (SSC) is an important effect for cosmological analyses that use the deep structure of the cosmic web; it may, however, be nontrivial to include it practically in a pipeline. We solve this difficulty by presenting a…

Accurate covariance matrices for two-point functions are critical for inferring cosmological parameters in likelihood analyses of large-scale structure surveys. Among various approaches to obtaining the covariance, analytic computation is…

宇宙学与河外天体物理 · 物理学 2021-02-23 Xiao Fang , Tim Eifler , Elisabeth Krause

This paper explores a variety of topics related to the question of testing the equality of covariance matrices in multivariate linear models, particularly in the MANOVA setting. The main focus is on graphical methods that can be used to…

统计方法学 · 统计学 2018-05-16 Michael Friendly , Matthew Sigal

The covariance matrix plays a fundamental role in many modern exploratory and inferential statistical procedures, including dimensionality reduction, hypothesis testing, and regression. In low-dimensional regimes, where the number of…

统计方法学 · 统计学 2024-11-12 Philippe Boileau , Nima S. Hejazi , Mark J. van der Laan , Sandrine Dudoit

We constrain the basic comological parameters using the first observations by the Very Small Array (VSA) in its extended configuration, together with existing cosmic microwave background data and other cosmological observations. We estimate…

Estimating large covariance and precision matrices are fundamental in modern multivariate analysis. The problems arise from statistical analysis of large panel economics and finance data. The covariance matrix reveals marginal correlations…

统计方法学 · 统计学 2015-04-17 Jianqing Fan , Yuan Liao , Han Liu

Current and upcoming cosmological observations allow us to probe structures on smaller and smaller scales, entering highly nonlinear regimes. In order to obtain theoretical predictions in these regimes, large cosmological simulations have…

In many astrophysical settings covariance matrices of large datasets have to be determined empirically from a finite number of mock realisations. The resulting noise degrades inference and precludes it completely if there are fewer…

天体物理仪器与方法 · 物理学 2017-01-11 Benjamin Joachimi

We explore a variety of statistics of clusters selected with cosmic shear measurement by utilizing both analytic models and large numerical simulations. We first develop a halo model to predict the abundance and the clustering of weak…

宇宙学与河外天体物理 · 物理学 2015-09-16 Masato Shirasaki , Takashi Hamana , Naoki Yoshida

The problem of testing changes in covariance has received increasing attention in recent years, especially in the context of high-dimensional testing. A number of approaches have been proposed, all limited to the two-sample problem and…

统计方法学 · 统计学 2016-09-06 Yi-Hui Zhou

We find a simple, accurate model for the covariance matrix of the real-space cosmological matter power spectrum on slightly nonlinear scales (k~0.1-0.8 h/Mpc at z=0), where off-diagonal matrix elements become substantial. The model includes…

宇宙学与河外天体物理 · 物理学 2011-06-30 Mark C. Neyrinck