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In this paper, the Janashia-Lagvilava matrix spectral factorization algorithm, which is designed for power spectral density functions defined on the unit circle, is extended to the real line. The proposed algorithm can be used directly for…

Complex Variables · Mathematics 2024-02-12 Lasha Ephremidze

We consider three different ways of algorithmization of the Janashia-Lagvilava spectral factorization method. The first algorithm is faster than the second one, however, it is only suitable for matrices of low dimension. The second…

Numerical Analysis · Mathematics 2017-03-20 L. Ephremidze , F. Saied , I. Spitkovsky

Spectral factorization is a prominent tool with several important applications in various areas of applied science. Wiener and Masani proved the existence of matrix spectral factorization. Their theorem has been extended to the…

Complex Variables · Mathematics 2021-06-01 Lasha Ephremidze , Ilya M. Spitkovsky

Spectral factorization is a powerful mathematical tool with diverse applications in signal processing and beyond. The Janashia-Lagvilava method has emerged as a leading approach for matrix spectral factorization. In this paper, we extend a…

Complex Variables · Mathematics 2025-03-05 Ying Wang , Lasha Ephremidze , Ronaldo Garcıa Reyes , Pedro Valdes-Sosa

In the present paper, we estimate the convergence rate in the Janashia-Lagvilava spectral factorization algorithm (see Studia Mathematica, 137, 1999, 93-100) under the restriction on a spectral density matrix that its inverse is integrable.

Complex Variables · Mathematics 2007-11-19 Lasha Ephremidze , Nobuhiko Fujii

The restriction imposed on the J-matrix method of using specific L2 bases is lifted without compromising any of the advantages that it offers. This opens the door to a wider range of application of the method to physical problems beyond the…

Atomic Physics · Physics 2009-11-07 H. A. Yamani , A. D. Alhaidari , M. S. Abdelmonem

Spectral inference provides fast algorithms and provable optimality for latent topic analysis. But for real data these algorithms require additional ad-hoc heuristics, and even then often produce unusable results. We explain this poor…

Machine Learning · Computer Science 2016-11-02 Moontae Lee , David Bindel , David Mimno

In this paper, we enhance a recent algorithm for approximate spectral factorization of matrix functions, extending its capabilities to precisely factorize rational matrices when an exact lower-upper triangular factorization is available.…

Complex Variables · Mathematics 2023-12-07 Lasha Ephremidze , Gennady Mishuris , Ilya Spitkovsky

In a recent paper a class of infinite Jacobi matrices with discrete character of spectra has been introduced. With each Jacobi matrix from this class an analytic function is associated, called the characteristic function, whose zero set…

Spectral Theory · Mathematics 2015-10-07 F. Stampach , P. Stovicek

A new method of matrix spectral factorization is proposed which reliably computes an approximate spectral factor of any matrix spectral density that admits spectral factorization

Complex Variables · Mathematics 2009-09-30 Gigla Janashia , Edem Lagvilava , Lasha Ephremidze

We investigate the effects of the regularization procedure used in the J-Matrix method. We show that it influences the convergence, and propose an alternative regularization approach. We explicitly perform some model calculations to…

Nuclear Theory · Physics 2007-05-23 J. Broeckhove , V. Vasilevsky , F. Arickx , A. Sytcheva

Non-negative matrix factorization (NMF) is a prob- lem with many applications, ranging from facial recognition to document clustering. However, due to the variety of algorithms that solve NMF, the randomness involved in these algorithms,…

Numerical Analysis · Mathematics 2018-12-17 Connor Sell , Jeremy Kepner

The J-matrix method was developed to handle regular short-range scattering potentials. Its accuracy, stability, and convergence properties compare favorably with other successful scattering methods. Recently, we extended the method to the…

Quantum Physics · Physics 2015-04-08 A. D. Alhaidari , H. Bahlouli , S. Al-Marzoug , M. S. Abdelmonem

The spectral factorization mapping $F\to F^+$ puts a positive definite integrable matrix function $F$ having an integrable logarithm of the determinant in correspondence with an outer analytic matrix function $F^+$ such that $F =…

Complex Variables · Mathematics 2019-07-31 Lasha Ephremidze , Eugene Shargorodsky , Ilya Spitkovsky

Para-Hermitian polynomial matrices obtained by matrix spectral factorization lead to functions useful in control theory systems, basis functions in numerical methods or multiscaling functions used in signal processing. We introduce a fast…

Numerical Analysis · Mathematics 2023-12-12 Vasil Kolev , Todor Cooklev , Fritz Keinert

This paper is concerned with the factorization and equivalence problems of multivariate polynomial matrices. We present some new criteria for the existence of matrix factorizations for a class of multivariate polynomial matrices, and obtain…

Symbolic Computation · Computer Science 2020-10-15 Dong Lu , Dingkang Wang , Fanghui Xiao

In this paper, we introduce and provide a short overview of nonnegative matrix factorization (NMF). Several aspects of NMF are discussed, namely, the application in hyperspectral imaging, geometry and uniqueness of NMF solutions,…

Numerical Analysis · Computer Science 2017-03-03 Nicolas Gillis

Sparse matrix factorization is the problem of approximating a matrix $\mathbf{Z}$ by a product of $J$ sparse factors $\mathbf{X}^{(J)} \mathbf{X}^{(J-1)} \ldots \mathbf{X}^{(1)}$. This paper focuses on identifiability issues that appear in…

Machine Learning · Computer Science 2021-11-18 Léon Zheng , Elisa Riccietti , Rémi Gribonval

We use the tools of the J-matrix method to evaluate the S-matrix and then deduce the bound and resonance states energies for singular screened Coulomb potentials, both analytic and piecewise differentiable. The J-matrix approach allows us…

Quantum Physics · Physics 2011-06-27 M. S. Abdelmonem , I. Nasser , H. Bahlouli , U. Al-Khawaja , A. D. Alhaidari

A spectral factorization theorem is proved for polynomial rank-deficient matrix-functions. The theorem is used to construct paraunitary matrix-functions with first rows given.

Complex Variables · Mathematics 2010-08-19 Lasha Ephremidze , Edem Lagvilava
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