Spitéri, Pierre and ZianeKhodja, Liane and Couturier, Raphaël Asynchronous parallel multisplitting mixed methods. (2019) In: 6th International Conference on Parallel, Distributed, GPU and Cloud Computing for Engineering (PARENG 2019), 4 June 2019  5 June 2019 (Pécs, Hungary).

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Official URL: https://doi.org/10.4203/ccp.112.15
Abstract
The present study is related to the analysis and application of mixed multisplitting methods to solve pseudo  linear stationary problems. These problems are stationary either intrinsically or as the result of the discretization of time evolution problems by implicit or semiimplicit time marching schemes. The considered problems are defined as an affine application AUF perturbed by an increasing diagonal operator. In the following A has the property of being a large dimensional Mmatrix, F is a vector, U is the unknown vector. Note that this type of problem occurs when solving elliptic, parabolic or hyperbolic second order boundaryvalue problems. Note also that the Mmatrix property is well verified after discretization by classical finite differences, finite volumes or finite elements provided that the angle condition is verified. In this case the problem will be solved by a specific method corresponding to a local linearization and to the implementation of the iterative Newton method. Thus, a large sparse linear system must be solved. This linear system is then associated with a fixed point problem and we intend to solve it by asynchronous parallel iterations. Taking into account the properties of the matrix A and the operator’s monotony properties, it is shown that fixed point applications are contractive with respect to an uniform weighted norm, which ensures on the one hand the existence and uniqueness of the solution of the algebraic system to be solved and on the other hand the convergence of asynchronous parallel iterations towards the solution of the problem. In addition, in order to unify the presentation and analysis of the algorithm behavior, we consider multisplitting methods that unify the presentation of subdomain methods, either to model subdomain methods without overlap, or to model subdomain methods with overlap such as Schwarz’s alternating method. These multisplitting methods are then applied to solve the target problem, the convergence analysis being still carried out by contraction techniques with respect to a weighted uniform norm. From an implementation point of view, we consider a mixed algorithm constituted by a two stage iterative algorithm, where the outer iteration is the multisplitting method and the inner iteration is the Krylov based iterative method, typically the GMRES method. As applications, we consider a diffusion convection problem perturbed by an increasing diagonal operator, the problem being solved by a mixed Newton  multisplitting method.
Item Type:  Conference or Workshop Item (Paper) 

Additional Information:  Thanks to Computational & Technology Resources. ISSN 17593433. The definitive version is available at: https://www.ctresources.info/ccp/paper.html?id=9282 
Audience (conference):  International conference proceedings 
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Institution:  French research institutions > Centre National de la Recherche Scientifique  CNRS (FRANCE) Université de Toulouse > Institut National Polytechnique de Toulouse  Toulouse INP (FRANCE) Université de Toulouse > Université Toulouse III  Paul Sabatier  UT3 (FRANCE) Université de Toulouse > Université Toulouse  Jean Jaurès  UT2J (FRANCE) Université de Toulouse > Université Toulouse 1 Capitole  UT1 (FRANCE) Other partners > Université Bourgogne FrancheComté  UBFC (FRANCE) 
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Deposited On:  16 Jul 2020 11:39 
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