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20192025
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math.NA2025

Outlier-free isogeometric discretizations for Laplace eigenvalue problems: closed-form eigenvalue and eigenvector expressions

Noureddine Lamsahel, Carla Manni, Ahmed Ratnani +2

We derive explicit closed-form expressions for the eigenvalues and eigenvectors of the matrices resulting from isogeometric Galerkin discretizations based on outlier-free spline su…

math.NA2022

A smoothing analysis for multigrid methods applied to tempered fractional problems

D. Ahmad, M. Donatelli, M. Mazza +2

We consider the numerical solution of time-dependent space tempered fractional diffusion equations. The use of Crank-Nicolson in time and of second-order accurate tempered weighted…

math.NA2022

Fast algebraic multigrid for block-structured dense and Toeplitz-like-plus-Cross systems arising from nonlocal diffusion problems

Minghua Chen, Rongjun Cao, Stefano Serra-Capizzano

Algebraic multigrid (AMG) is one of the most efficient iterative methods for solving large sparse system of equations. However, how to build/check restriction and prolongation oper…

math.NA2022

Fast Toeplitz eigenvalue computations, joining interpolation-extrapolation matrix-less algorithms and simple-loop theory

M. Bogoya, S. E. Ekström, S. Serra-Capizzano

Under appropriate technical assumptions, the simple-loop theory allows to deduce various types of asymptotic expansions for the eigenvalues of Toeplitz matrices generated by a func…

math.NA2020

Multilevel symmetrized Toeplitz structures and spectral distribution results for the related matrix-sequences

Paola Ferrari, Isabella Furci, Stefano Serra-Capizzano

In recent years, motivated by computational purposes, the singular value and spectral features of the symmetrization of Toeplitz matrices generated by a Lebesgue integrable functio…

math.NA2020

Asymptotic spectra of large (grid) graphs with a uniform local structure

Andrea Adriani, Davide Bianchi, Stefano Serra-Capizzano

We are concerned with sequences of graphs having a grid geometry, with a uniform local structure in a bounded domain , . We assume to be Lebesgu…