Results 21 to 30 of about 5,336 (304)
Circulant preconditioners for mean curvature-based image deblurring problem
Journal of Algorithms & Computational Technology, 2021 The mean curvature-based image deblurring model is widely used to enhance the quality of the deblurred images. However, the discretization of the associated Euler–Lagrange equations produces a nonlinear ill-conditioned system which affects the ...
Shahbaz Ahmad, Faisal Fairag
doaj +1 more source
Nuclear Engineering and Technology, 2022 In this paper, a new multi-group neutron-gamma transport calculation code system STRAUM-MATXST for complicated geometrical problems is introduced and its development status including numerical tests is presented.
MyeongHyeon Woo, Ser Gi Hong
doaj +1 more source
Mixed-dimensional auxiliary space preconditioners [PDF]
, 2020 This work introduces nodal auxiliary space preconditioners for discretizations of mixed-dimensional partial differential equations. We first consider the continuous setting and generalize the regular decomposition to this setting.
Budisa, Ana +5 more
core +1 more source
Axioms, 2018 This work studies limited memory preconditioners for linear symmetric positive definite systems of equations. Connections are established between a partial Cholesky factorization from the literature and a variant of Quasi-Newton type preconditioners ...
Benedetta Morini
doaj +1 more source
Preconditioning Large Indefinite Linear Systems
Sultan Qaboos University Journal for Science, 2011 After briefly recalling some relevant approaches for preconditioning large symmetric linear systems, we describe a novel class of preconditioners. Our proposal is tailored for large indefinite linear systems, which arise very frequently in many different
Giovanni Fasano, Massimo Roma
doaj +1 more source
Preconditioners for nonconforming discretizations [PDF]
Mathematics of Computation, 1996 We prove an abstract norm equivalence for a two-level method, which allows us to reduce the construction of preconditioners for nonconforming finite element discretizations to known cases of conforming elements.
openaire +1 more source
Abstract robust coarse spaces for systems of PDEs via generalized eigenproblems in the overlaps [PDF]
, 2013 Coarse spaces are instrumental in obtaining scalability for domain decomposition methods for partial differential equations (PDEs). However, it is known that most popular choices of coarse spaces perform rather weakly in the presence of heterogeneities ...
Hauret, P. +12 more
core +1 more source
A Multipole Approach for Preconditioners [PDF]
, 2002 A new class of approximate inverse preconditioners is presented for solving large linear systems with an iterative method. It is at the intersection of multipole, multigrid and SPAI methods. The method consists in approximating the inverse of a matrix by a block constant matrix, instead of approximating it by a sparse matrix as in SPAI methods. It does
Ph. Guillaume, A. Huard, C. Le Calvez
openaire +1 more source
Block preconditioners for linear systems arising from multiscale collocation with compactly supported RBFs [PDF]
, 2014 Symmetric collocation methods with RBFs allow approximation of the solution of a partial differential equation, even if the right-hand side is only known at scattered data points, without needing to generate a grid.
Pestana, Jennifer +3 more
core +1 more source
Generating Approximate Inverse Preconditioners for Sparse Matrices Using CUDA and GPGPU
Journal of Algorithms & Computational Technology, 2011 The problem of numerical solution of sparse matrix-based linear systems arises from many scientific applications. Iterative solvers and corresponding preconditioning techniques are usually adopted.
Shiming Xu +3 more
doaj +1 more source