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Listar por autor "Mas Marí, José"

Mostrando ítems 1-20 de 21

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A Survey on Nikodým and Vitali-Hahn-Saks Properties

López Alfonso, Salvador; López-Pellicer, Manuel; Mas Marí, José (Y&#305lmaz Simsek, 2021)

[EN] Let ba(A) be the Banach space of the real (or complex) finitely additive measures of bounded variation defined on an algebra A of subsets of Omega and endowed with the variation norm. . A subset B of A is a Nikod ́ym ...
A two-level ILU preconditioner for electromagnetic applications

Cerdán Soriano, Juana Mercedes; Marín Mateos-Aparicio, José; Mas Marí, José (Elsevier, 2017)

[EN] Computational electromagnetics based on the solution of the integral form of Maxwell s equations with boundary element methods require the solution of large and dense linear systems. For large-scale problems the ...
An Algorithm for the Single-Input Pole Assignment Problem

Bru, Rafael; Mas Marí, José; Urbano Salvador, Ana María (Society for Industrial and Applied Mathematics, 1994)

[EN] B. N. Datta and K. Datta have proposed an efficient parallel algorithm for the single-input pole assignment problem when the spectrum set to be assigned is pairwise distinct and disjoint from the spectrum of the ...
An inverse LU preconditioner based on the Sherman-Morrison formula

Bru García, Rafael; Cerdán Soriano, Juana Mercedes; Marín Mateos-Aparicio, José; Mas Marí, José (Universitatea "Ovidius" Constanta, 2024-04-01)

[EN] An approximate inverse LU preconditioner is constructed based on the Sherman-Morrison formula. Applying recursively that inversion formula a multiplicative decomposition of the inverse of a matrix is obtained. This ...
Application of the Jacobi Davidson method for spectral low-rank preconditioning in computational electromagnetics problems

Mas Marí, José; Cerdán Soriano, Juana Mercedes; Malla Martínez, Natalia; Marín Mateos-Aparicio, José (Springer, 2015-01)

[EN] We consider the numerical solution of linear systems arising from computational electromagnetics applications. For large scale problems the solution is usually obtained iteratively with a Krylov subspace method. It ...
Balanced incomplete factorization preconditioner with pivoting

Marín Mateos-Aparicio, José; Mas Marí, José (Springer-Verlag, 2023-01)

[EN] In this work we study pivoting strategies for the preconditioner presented in Bru (SIAM J Sci Comput 30(5):2302-2318, 2008) which computes the LU factorization of a matrix A. This preconditioner is based on the Inverse ...
Block approximate inverse preconditioners for sparse nonsymmetric linear systems

Cerdán Soriano, Juana Mercedes; Faraj El Guelei, Táher; Malla Martínez, Natalia; Marín Mateos-Aparicio, José; Mas Marí, José (KENT STATE UNIVERSITY, ETNA, DEPT MATHEMATICS & COMPUTER SCIENCE, KENT, USA, OH, 44242-0001, 2010)

[EN] In this paper block approximate inverse preconditioners to solve sparse nonsymmetric linear systems with iterative Krylov subspace methods are studied. The computation of the preconditioners involves consecutive updates ...
Classes of general H-matrices

Bru, R.; Corral Ortega, Cristina; Gimenez Manglano, María Isabel; Mas Marí, José (Elsevier, 2008)

[EN] Let M(A) denote the comparison matrix of a square H-matrix A, that is, M(A) is an M-matrix. H-matrices such that their comparison matrices are non-singular are well studied in the literature. In this paper, we study ...
Conjuntos que determinan la acotación uniforme

López Alfonso, Salvador (Universitat Politècnica de València, 2016-12-16)

The classical Nykodym theorem (1933) asserts that a set H of countably additive complex measures defined on a sigma-algebra S which is bounded for each element of S, then H is uniformly bounded on S. It is well known that ...
Improved balanced incomplete factorization

Bru García, Rafael; Marín Mateos-Aparicio, José; Mas Marí, José; Tuma, Miroslav (Society for Industrial and Applied Mathematics, 2010)

[EN] . In this paper we improve the BIF algorithm which computes simultaneously the LU factors (direct factors) of a given matrix and their inverses (inverse factors). This algorithm was introduced in [R. Bru, J. Mar´ın, ...
Low-rank update of preconditioners for the nonlinear Richard's equation

Bergamaschi, Luca; Bru García, Rafael; Martínez Calomardo, Ángeles; Mas Marí, José; Putti, Mario (Elsevier, 2013-01-09)

Preconditioners for the Conjugate Gradient method are studied to solve the Newton system with symmetric positive definite (SPD) Jacobian. Following the theoretical work in Bergamaschi et al. (2011) [4] we start from a given ...
Low-rank updates of balanced incomplete factorization preconditioners

Cerdán Soriano, Juana Mercedes; Marín Mateos-Aparicio, José; Mas Marí, José (Springer-Verlag, 2017)

[EN] Let Ax = b be a large and sparse system of linear equations where A is a nonsingular matrix. An approximate solution is frequently obtained by applying preconditioned terations. Consider the matrix B = A + PQT where ...
Nikodym boundedness property for webs in sigma-algebras

López Alfonso, Salvador; Mas Marí, José; Moll López, Santiago Emmanuel (Springer-Verlag, 2016)

[EN] A subset B of an algebra A of subsets of Omega is said to have property N if a B-pointwise bounded subset M of ba(A ) is uniformly bounded on A , where ba(A ) is the Banach space of the real (or complex) finitely ...
On Updating Preconditioners for the Iterative Solution of Linear Systems

Guerrero Flores, Danny Joel (Universitat Politècnica de València, 2018-07-02)

El tema principal de esta tesis es el desarrollo de técnicas de actualización de precondicionadores para resolver sistemas lineales de gran tamaño y dispersos Ax=b mediante el uso de métodos iterativos de Krylov. Se ...
Pivoting in ISM factorizations

Mas Marí, José; Marín Mateos-Aparicio, José (Universitat Politècnica de València, 2022-07-15)

[EN] In this work we study pivoting strategies for the preconditioner presented Balanced Incomplete Preconditioner (SIAM J Sci Comput 30(5):2302¿2318, 2008) which computes the LU factorization of a matrix A. We present a ...
Preconditioned iterative methods for solving linear least squares problems

Bru García, Rafael; Marín Mateos-Aparicio, José; Mas Marí, José; Tuma, Miroslav (Society for Industrial and Applied Mathematics, 2014)

New preconditioning strategies for solving m × n overdetermined large and sparse linear least squares problems using the conjugate gradient for least squares (CGLS) method are described. First, direct preconditioning of ...
Preconditioners based on the ISM factorization

Bru García, Rafael; Cerdán Soriano, Juana Mercedes; Marín Mateos-Aparicio, José; Mas Marí, José; Tuma, Miroslav (Tipografia Universitatii Ovidius, 2015)

In this paper we survey our work on preconditioners based on the Inverse Sherman-Morrison factorization. The most important theoretical results are also summarized and some numerical conclusions are provided.
Preconditioners for nonsymmetric linear systems with low-rank skew-symmetric part

Cerdán Soriano, Juana Mercedes; Guerrero-Flores, Danny Joel; Marín Mateos-Aparicio, José; Mas Marí, José (Elsevier, 2018-12-01)

[EN] We present a preconditioning technique for solving nonsymmetric linear systems Ax = b, where the coefficient matrix A has a skew-symmetric part that can be well approximated with a skew-symmetric low-rank matrix. The ...
Preconditioners for rank deficient least squares problems

Cerdán Soriano, Juana Mercedes; Guerrero, D.; Marín Mateos-Aparicio, José; Mas Marí, José (Elsevier, 2020-07)

[EN] In this paper we present a method for computing sparse preconditioners for iteratively solving rank deficient least squares problems (LS) by the LSMR method. The main idea of the method proposed is to update an ...
Schur complement of general H-matrices

Bru García, Rafael; Corral Ortega, Cristina; Gimenez Manglano, María Isabel; Mas Marí, José (John Wiley & Sons, 2009)

[EN] It is well known that the Schur complement of some H-matrices is an H-matrix. In this paper, the Schur complement of any general H-matrix is studied. In particular, it is proved that the Schur complement, if it exists, ...