National Repository of Grey Literature 33 records found  beginprevious20 - 29next  jump to record: Search took 0.01 seconds. 
Numerical comparison of different choices of interface weights in the BDDC method
Čertíková, M. ; Burda, P. ; Šístek, Jakub
Balancing Domain Decomposition by Constraints (BDDC) belongs to the class of primal substructuring Domain Decomposition (DD) methods. DD methods are iterative methods successfully used in engineering to parallelize solution of large linear systems arising from discretization of second order elliptic problems. Substructuring DD methods represent an important class of DD methods. Their main idea is to divide the underlying domain into nonoverlapping subdomains and solvemany relatively small, local problems on subdomains instead of one large problem on the whole domain. In primal methods, it has to be specified how to distribute interface residuals among subdomains and how to obtain global, interface values of solution from local values on adjacent subdomains. Usually a weighted average is used with some simple choice of weights.
Programs and Algorithms of Numerical Mathematics 15
Vejchodský, Tomáš ; Chleboun, J. ; Přikryl, Petr ; Segeth, Karel ; Šístek, Jakub
The book contains papers presented at the international seminar Programs and algorithms of numerical Mathematics 15 (PANM 15), held in Dolni Maxov, Czech Republic, June 6-11, 2010. It is the fifteen volume in the series of the PANM proceedings. The topics of contributions include numerical methods for fluid flow modelling, the finite element method, a posteriori error estimates, topics from numerical linear atgebra, etc.
Some remarks on averaging in the BDDC method
Čertíková, M. ; Burda, P. ; Novotný, J. ; Šístek, Jakub
In this paper, we introduce a general framework for derivation of the averaging operator, from hich the standard choices are recovered by simplifications. Then, an alternative approach derived by another simplification is proposed and tested on a 2D example.
Approaches to parallel implementation of the BDDC method
Šístek, Jakub ; Burda, P. ; Čertíková, M. ; Novotný, J.
During past several years, we have implemented and tested various approaches to domain decomposition methods, especially the Balancing Domain Decomposition Method by Constraints (BDDC). The goal of this paper is to summarize our experience with parallel implementation of such algorithms and to suggest ways to an implementation of the BDDC method that would be efficient on very large number of cores of computers of near future.
On selections of constraints for the BDDC method
Čertíková, M. ; Šístek, Jakub ; Novotný, J. ; Burda, P.
The Balancing Domain Decomposition by Constraints (BDDC) method is an iterative substructuring domain decomposition method which uses a coarse space. The choice of coarse constraints on continuity has strong influence on convergence of the method. The goal of this paper is to compare the performance of several algorithms for selection of the coarse constraints applied to both test and industrial 3D linear elasticity problems and confront results obtained for typical test problems with results for industrial problems.
Fluid flow in cavity solved by finite element method
Burda, P. ; Novotný, J. ; Šístek, Jakub
The problem of singularities caused by boundary conditions is studied in the flow of lid driven cavity. The asymptotic behaviour near the singularity points is used together with the apriori error estimates of the finite element solution, in order to design the finite element mesh adjusted to singularity. A posteriori error estimates are used as the principal tool for error analysis. Thus we obtain very precise solution in the vicinity of the singularity. Numerical results are presented.
Study of using corners for BDDC in 3D
Čertíková, M. ; Burda, P. ; Novotný, J. ; Šístek, Jakub
Existing algorithms for selection of corners in BDDC are atudied and a new algorithm is proposed. This combines advantages of previous algorithms. The new algorithm is applied to a benchmark and an industrial problem of linear elasticity.
Application of the BDDC method to the Stokes problem
Šístek, Jakub ; Burda, P. ; Mandel, J. ; Novotný, J. ; Sousedík, B.
Application of BDDC method to problems of Stokes flow is explored. BDDC is applied to several 3D problems and is shown to be a competitive method.
Implementace metody BDDC založená na forntálním a multifrontálním řešiči
Šístek, Jakub ; Novotný, Jaroslav ; Burda, Pavel ; Čertíková, Marta
A parallel implementation of the BDDC method is presented. It is based on frontal solver for subdomain problems, while the coarse problem is solved by a multifrontal algorithm. Results for an industrial problem of mine reel are included.
Modelování problémů proudění nestlačitelné tekutiny metodou konečných prvků
Burda, P. ; Novotný, Jaroslav ; Šístek, Jakub ; Damašek, Alexandr
We deal with modelling of flows in channels with abrupt changes of the diameter. We use a posteriori error estimates and adaptive strategy. We obtain solution with desired precision also in the vicinity of the corner, though there is a singularity.

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