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We introduce a fast algorithm for Gaussian process regression in low dimensions, applicable to a widely-used family of non-stationary kernels. The non-stationarity of these kernels is induced by arbitrary spatially-varying vertical and…

Numerical Analysis · Mathematics 2025-03-28 P. Michael Kielstra , Michael Lindsey

We explore the use of galaxy bispectra with multitracer technique as a possible probe of primordial non-Gaussianities. We forecast future constraints on non-linearity parameters, $f_{\rm NL}^{\rm eq}$ and $f_{\rm NL}^{\rm orth}$, which…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-12 Daisuke Yamauchi , Shuichiro Yokoyama , Keitaro Takahashi

We propose a method to estimate non-Gaussian error bars on the matter power spectrum from galaxy surveys in the presence of non-trivial survey selection functions. The estimators are often obtained from formalisms like FKP and PKL, which…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Joachim Harnois-Deraps , Ue-Li Pen

The next generation of Department of Energy supercomputers will be capable of exascale computation. For these machines, far more computation will be possible than that which can be saved to disk. As a result, users will be unable to rely on…

Machine Learning · Computer Science 2025-07-23 Michael Grosskopf , Kellin Rumsey , Ayan Biswas , Earl Lawrence

3D Gaussian Splatting (3DGS) is widely used for novel view synthesis due to its high rendering quality and fast inference time. However, 3DGS predominantly relies on first-order optimizers such as Adam, which leads to long training times.…

Computer Vision and Pattern Recognition · Computer Science 2026-01-27 Hamza Pehlivan , Andrea Boscolo Camiletto , Lin Geng Foo , Marc Habermann , Christian Theobalt

This paper deals with Gibbs samplers that include high dimensional conditional Gaussian distributions. It proposes an efficient algorithm that avoids the high dimensional Gaussian sampling and relies on a random excursion along a small set…

Computation · Statistics 2016-04-20 Olivier Féron , François Orieux , Jean-François Giovannelli

Building on previous developments of a harmonic decomposition framework for computing the three-point correlation function (3PCF) of projected scalar fields over the sky, this work investigates how much cosmological information is contained…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-16 Sofia Samario-Nava , Alejandro Aviles , Juan Carlos Hidalgo

Large-scale Fourier modes of the cosmic density field are of great value for learning about cosmology because of their well-understood relationship to fluctuations in the early universe. However, cosmic variance generally limits the…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-05 Omar Darwish , Simon Foreman , Muntazir M. Abidi , Tobias Baldauf , Blake D. Sherwin , P. Daniel Meerburg

The nonlinear Fourier transform (NFT) has recently gained significant attention in fiber optic communications and other engineering fields. Although several numerical algorithms for computing the NFT have been published, the design of…

Signal Processing · Electrical Eng. & Systems 2019-10-17 Shrinivas Chimmalgi , Peter J. Prins , Sander Wahls

Correlations in the Lyman-$\alpha$ (Ly$\alpha$) forest, both as a function of line of sight separation (1D) and 3D separation, provide a unique window to the distribution of matter at redshifts not accessible by current galaxy surveys.…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-07 Martine Lokken , Andreu Font-Ribera , Patrick McDonald

We present an algorithm for quickly generating multiple realizations of N-body simulations to be used, for example, for cosmological parameter estimation from surveys of large-scale structure. Our algorithm uses a new method to resample the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Michael D. Schneider , Shaun Cole , Carlos S. Frenk , Istvan Szapudi

We present an algorithm that computes the multipole coefficients of the galaxy three-point correlation function (3PCF) without explicitly considering triplets of galaxies. Rather, centering on each galaxy in the survey, it expands the…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-04 Zachary Slepian , Daniel J. Eisenstein

We reconstruct the dark matter density field from spatially overlapping spectroscopic and photometric redshift catalogs through a forward modelling approach. Instead of directly inferring the underlying density field, we find the best…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-01 Benjamin Horowitz , Peter Melchior

We present $\mathcal{O}(N^2)$ estimators for the small-scale power spectrum and bispectrum in cosmological simulations. In combination with traditional methods, these allow spectra to be efficiently computed across a vast range of scales,…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-21 Oliver H. E. Philcox

Field-level inference has emerged as a promising framework to fully harness the cosmological information encoded in next-generation galaxy surveys. It involves performing Bayesian inference to jointly estimate the cosmological parameters…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-19 Hugo Simon , François Lanusse , Arnaud de Mattia

We study the covariance properties of real space correlation function estimators -- primarily galaxy-shear correlations, or galaxy-galaxy lensing -- using SDSS data for both shear catalogs and lenses (specifically the BOSS LOWZ sample).…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-30 Sukhdeep Singh , Rachel Mandelbaum , Uroš Seljak , Anže Slosar , Jose Vazquez Gonzalez

Structural parameters are normally extracted from observed galaxies by fitting analytic light profiles to the observations. Obtaining accurate fits to high-resolution images is a computationally expensive task, requiring many model…

Instrumentation and Methods for Astrophysics · Physics 2015-03-17 Benjamin R. Barsdell , David G. Barnes , Christopher J. Fluke

Higher-order spectra (Brillinger's polyspectra) offer powerful methods for solving critical problems in signal processing and data analysis. Despite their significant potential, their practical use has remained limited due to unresolved…

Data Analysis, Statistics and Probability · Physics 2025-07-24 Markus Sifft , Armin Ghorbanietemad , Fabian Wagner , Daniel Hägele

Many developments in Mathematics involve the computation of higher order derivatives of Gaussian density functions. The analysis of univariate Gaussian random variables is a well-established field whereas the analysis of their multivariate…

Computation · Statistics 2022-03-04 José E. Chacón , Tarn Duong

Gaussian time-series models are often specified through their spectral density. Such models present several computational challenges, in particular because of the non-sparse nature of the covariance matrix. We derive a fast approximation of…

Computation · Statistics 2012-11-20 Nicolas Chopin , Judith Rousseau , Brunero Liseo