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pro vyhledávání: '"Capizzano, A A"'
In recent years, there has been a renewed interest in preconditioning for multilevel Toeplitz systems, a research field that has been extensively explored over the past several decades. This work introduces novel preconditioning strategies using mult
Externí odkaz:
http://arxiv.org/abs/2409.20363
In the present study, we consider the Extra-Membrane-Intra model (EMI) for the simulation of excitable tissues at the cellular level. We provide the (possibly large) system of partial differential equations (PDEs), equipped with ad hoc boundary condi
Externí odkaz:
http://arxiv.org/abs/2409.13432
In recent years more and more involved block structures appeared in the literature in the context of numerical approximations of complex infinite dimensional operators modeling real-world applications. In various settings, thanks the theory of genera
Externí odkaz:
http://arxiv.org/abs/2409.06465
Here, we consider a more general class of matrix-sequences and we prove that they belong to the maximal $*$-algebra of generalized locally Toeplitz (GLT) matrix-sequences. Then, we identify the associated GLT symbols and GLT momentary symbols in the
Externí odkaz:
http://arxiv.org/abs/2407.00792
Autor:
Adriani, Andrea, Schiavoni-Piazza, Alec Jacopo Almo, Serra-Capizzano, Stefano, Tablino-Possio, Cristina
In the current note we consider matrix-sequences $\{B_{n,t}\}_n$ of increasing sizes depending on $n$ and equipped with a parameter $t>0$. For every fixed $t>0$, we assume that each $\{B_{n,t}\}_n$ possesses a canonical spectral/singular values symbo
Externí odkaz:
http://arxiv.org/abs/2405.20150
In the present study, we consider the numerical method for Toeplitz-like linear systems arising from the $d$-dimensional Riesz space fractional diffusion equations (RSFDEs). We apply the Crank-Nicolson (CN) technique to discretize the temporal deriva
Externí odkaz:
http://arxiv.org/abs/2404.10221
In the past decades, a remarkable amount of research has been carried out regarding fast solvers for large linear systems resulting from various discretizations of fractional differential equations (FDEs). In the current work, we focus on multigrid m
Externí odkaz:
http://arxiv.org/abs/2403.16352
Motivated by a recent work on a preconditioned MINRES for flipped linear systems in imaging, in this note we extend the scope of that research for including more precise boundary conditions such as reflective and anti-reflective ones. We prove spectr
Externí odkaz:
http://arxiv.org/abs/2402.12059
Autor:
Adriani, Andrea, Sormani, Rosita Luisa, Tablino-Possio, Cristina, Krause, Rolf, Serra-Capizzano, Stefano
The current study investigates the asymptotic spectral properties of a finite difference approximation of nonlocal Helmholtz equations with a Caputo fractional Laplacian and a variable coefficient wave number $\mu$, as it occurs when considering a wa
Externí odkaz:
http://arxiv.org/abs/2402.10569
Twenty years ago the anti-reflective numerical boundary conditions (BCs) were introduced in a context of signal processing and imaging, for increasing the quality of the reconstruction of a blurred signal/image contaminated by noise and for reducing
Externí odkaz:
http://arxiv.org/abs/2312.16485