Preconditioners
Mostrando 1-9 de 9 artigos, teses e dissertações.
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1. A New Hybrid Preconditioner for the Interior Point Method
RESUMO Este trabalho visa melhorar o cálculo da direção de busca no Método de Pontos Interiores primal-dual usando métodos iterativos precondicionados. Trata-se de uma abordagem híbrida que combina o precondicionador Fatoração Controlada de Cholesky e o precondicionador Separador. Esta abordagem tem mostrado bons resultados, entretanto, nesses préco
TEMA (São Carlos). Publicado em: 16/09/2019
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2. PRECONDITIONING ISSUES IN THE NUMERICAL SOLUTION OF NONLINEAR EQUATIONS AND NONLINEAR LEAST SQUARES
Second order methods for optimization call for the solution of sequences of linear systems. In this survey we will discuss several issues related to the preconditioning of such sequences. Covered topics include both techniques for building updates of factorized preconditioners and quasi-Newton approaches. Sequences of unsymmetric linear systems arising in Ne
Pesqui. Oper.. Publicado em: 2014-12
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3. Heuristics for implementation of a hybrid preconditioner for interior-point methods
This article presents improvements to the hybrid preconditioner previously developed for the solution through the conjugate gradient method of the linear systems which arise from interior-point methods. The hybrid preconditioner consists of combining two preconditioners: controlled Cholesky factorization and the splitting preconditioner used in different pha
Pesquisa Operacional. Publicado em: 2011-12
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4. Preconditioners for higher order finite element discretizations of H(div)-elliptic problem
In this paper, we are concerned with the fast solvers for higher order finite element discretizations of H(div)-elliptic problem. We present the preconditioners for the first family and second family of higher order divergence conforming element equations, respectively. By combining the stable decompositions of two kinds of finite element spaces with the abs
Computational & Applied Mathematics. Publicado em: 2010
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5. Métodos de fronteira imersa em mecânica dos fluidos / Immersed boundary methods in fluid mechanics
No desenvolvimento de códigos paralelos, a biblioteca PETSc se destaca como uma ferramenta prática e útil. Com o uso desta ferramenta, este trabalho apresenta um estudo sobre resolvedores de sistemas lineares aplicados a escoamentos incompressíveis de fluidos em microescala, além de uma análise de seu comportamento em paralelo. Após um estudo dos dive
Publicado em: 2010
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6. Matrix differential equations and inverse preconditioners
In this article, we propose to model the inverse of a given matrix as the state of a proper first order matrix differential equation. The inverse can correspond to a finite value of the independent variable or can be reached as a steady state. In both cases we derive corresponding dynamical systems and establish stability and convergence results. The applica
Computational & Applied Mathematics. Publicado em: 2007
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7. The algebric multigrid method for solving linear systems issued from the finite element method. / O método multigrid algébrico na resolução de sistemas lineares oriundos do método dos elementos finitos.
Este trabalho propõe uma nova abordagem, baseada em wavelets, para o método Multigrid Algébrico (WAMG). Nesta nova abordagem, a Transformada Discreta Wavelet é aplicada na matriz de coeficientes do sistema linear gerando uma aproximação dessa matriz em cada nível do processo de multiresolução. As vantagens da nova abordagem, que incluem maior facili
Publicado em: 2007
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8. SIMULAÇÃO DO ESCOAMENTO DE ÁGUA E ÓLEO EM MEIOS POROSOS / WATER AND OIL FLOW SIMULATION IN POROUS MEDIA
Many problems arising from real world can be represented by systems of partial diferential equations (PDE´s). However, the resulting discrete equations produce large and frequently bad conditioned matrices. This work implements the mixed finite element method to numerically solve a system of PDE´s coming from a multiphase flow in porous media model and imp
Publicado em: 2002
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9. SimulaÃÃo de reservatÃrio de petrÃleo em arquiteturas paralelas com memÃria distribuida
New codes have been developed for the solution of large scale models in reservoir simulations with high performance computing. This work shows the development of a petroleum reservoir simulator using distributed memory models for parallel computers. A two phase oil/water Black-Oil model was implemented and the resulting equations are discretized by ânite di
Publicado em: 2002