English
Related papers

Related papers: Comments on the Voigt function implementation in t…

200 papers

Recently, it has been recognised that very large spectroscopic surveys (several million spectra) are required to advance our understanding of Dark Energy (via baryonic wiggles) and the detailed history of our Local Group of galaxies (via…

Astrophysics · Physics 2009-11-13 Ian R. Parry

A fundamental problem in numerical analysis and approximation theory is approximating smooth functions by polynomials. A much harder version under recent consideration is to enforce bounds constraints on the approximating polynomial. In…

Numerical Analysis · Mathematics 2021-12-28 Larry Allen , Robert C. Kirby

This work presents a method of computing Voigt functions and their derivatives, to high accuracy, on a uniform grid. It is based on an adaptation of Fourier-transform based convolution. The relative error of the result decreases as the…

Data Analysis, Statistics and Probability · Physics 2007-05-23 Marcus H. Mendenhall

While nonlinear optical spectroscopy is becoming more commonly used to study the excited states of nonlinear-optical systems, a general theory of inhomogeneous broadening is rarely applied in lieu of either a simple Lorentzian or Gaussian…

Optics · Physics 2008-02-26 Robert J. Kruhlak , Mark G. Kuzyk

Variable Muckenhoupt weights are considered in variable exponent Lebesgue spaces. Applications are given for polynomial approximation in these spaces. Boundedness of averaging operator is proved to gain a transference result. Almost all…

Classical Analysis and ODEs · Mathematics 2021-09-02 Ramazam Akgün

One of the most useful techniques in astronomical instrumentation is image slicing. It enables a spectrograph to have a more compact angular slit, whilst retaining throughput and increasing resolving power. Astrophotonic components like the…

In this paper, we focus on the approximation of smooth functions $f: [-\pi, \pi] \rightarrow \mathbb{C}$, up to an unresolvable global phase ambiguity, from a finite set of Short Time Fourier Transform (STFT) magnitude (i.e., spectrogram)…

Numerical Analysis · Mathematics 2021-06-07 Mark Iwen , Michael Perlmutter , Nada Sissouno , Aditya Viswanathan

This paper studies approximate solutions of a linear fractional vector optimization problem without requiring boundedness of the constraint set. We establish necessary and sufficient conditions for approximating weakly efficient points of…

Optimization and Control · Mathematics 2024-12-12 Nguyen Thi Thu Huong

In this paper, we propose a new and simple approach to the approximation algorithms that are modified and improved from our published results. The computational and graphical examples are presented with the aid of Maple procedures.

Numerical Analysis · Mathematics 2025-06-24 Quan Le Phuong

The algorithm of modified wavelet analysis is discussed. It is based on the weighted least squares approximation. Contrary to the Gaussian as a weight function, we propose to use a compact weight function. The accuracy estimates using the…

Instrumentation and Methods for Astrophysics · Physics 2020-05-05 Ivan L. Andronov , Violetta P. Kulynska

Frequentist profile likelihoods have seen a resurgence in cosmology, offering an alternative to Bayesian methods as they can circumvent the impact of prior-volume effects. This paper presents Procoli, a fast and accessible package to obtain…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-26 Tanvi Karwal , Yashvi Patel , Alexa Bartlett , Vivian Poulin , Tristan L. Smith , Daniel N. Pfeffer

I describe an approach to fitting and comparison of radio spectra based on Bayesian analysis and realised using a new implementation of the nested sampling algorithm. Such an approach improves on the commonly used maximum-likelihood fitting…

Instrumentation and Methods for Astrophysics · Physics 2009-12-14 Bojan Nikolic

We describe an efficient algorithm for calculating the statistics of weak lensing by large-scale structure based on a tiled set of independent particle-mesh N-body simulations which telescope in resolution along the line of sight. This…

Astrophysics · Physics 2008-11-26 Martin White , Wayne Hu

The parent paper to this Addendum describes the optimisation theory on which VPFIT, a non-linear least-squares program for modelling absorption spectra, is based. In that paper, we show that Voigt function derivatives can be calculated…

Instrumentation and Methods for Astrophysics · Physics 2022-01-12 Chung-Chi Lee , John K. Webb , Robert F. Carswell

We strengthen the classical approximation theorems of Weierstrass, Runge and Mergelyan by showing the polynomial and rational approximants can be taken to have a simple geometric structure. In particular, when approximating a function $f$…

Complex Variables · Mathematics 2023-02-14 Christopher J. Bishop , Kirill Lazebnik

Given a graphical model (GM), computing its partition function is the most essential inference task, but it is computationally intractable in general. To address the issue, iterative approximation algorithms exploring certain local…

Machine Learning · Computer Science 2019-05-15 Sejun Park , Eunho Yang , Se-Young Yun , Jinwoo Shin

We present an approximation scheme for functions in three dimensions, that requires only their samples on the Cartesian grid, under the assumption that the functions are sufficiently concentrated in both space and frequency. The scheme is…

Numerical Analysis · Mathematics 2022-12-16 Rami Katz , Yoel Shkolnisky

The computation of Voronoi Diagrams, or their dual Delauney triangulations is difficult in high dimensions. In a recent publication Polianskii and Pokorny propose an iterative randomized algorithm facilitating the approximation of Voronoi…

Computational Geometry · Computer Science 2024-05-17 Alexander Sikorski , Martin Heida

We present recent evolutions of the detailed opacity code SCO-RCG which combines statistical modelings of levels and lines with fine-structure calculations. The code now includes the Partially-Resolved-Transition-Array model, which allows…

Solar and Stellar Astrophysics · Physics 2021-03-10 Jean-Christophe Pain , Franck Gilleron , Thomas Blenski