Sökning: "block preconditioner"
Visar resultat 1 - 5 av 11 avhandlingar innehållade orden block preconditioner.
1. Robust Preconditioners Based on the Finite Element Framework
Sammanfattning : Robust preconditioners on block-triangular and block-factorized form for three types of linear systems of two-by-two block form are studied in this thesis. The first type of linear systems, which are dense, arise from a boundary element type of discretization of crack propagation problems. LÄS MER
2. Efficient Solvers for Space-Time Discontinuous Galerkin Spectral Element Methods
Sammanfattning : In this thesis we study efficient solvers for space-time discontinuous Galerkin spectral element methods (DG-SEM). These discretizations result in fully implicit schemes of variable order in both spatial and temporal directions. LÄS MER
3. On Numerical Solution Methods for Block-Structured Discrete Systems
Sammanfattning : The development, analysis, and implementation of efficient methods to solve algebraic systems of equations are main research directions in the field of numerical simulation and are the focus of this thesis. Due to their lesser demands for computer resources, iterative solution methods are the choice to make, when very large scale simulations have to be performed. LÄS MER
4. Developments in preconditioned iterative methods with application to glacial isostatic adjustment models
Sammanfattning : This study examines the block lower-triangular preconditioner with element-wise Schur complement as the lower diagonal block applied on matrices arising from an application in geophysics. The element-wise Schur complement is a special approximation of the exact Schur complement that can be constructed in the finite element framework. LÄS MER
5. Robust preconditioned iterative solution methods for large-scale nonsymmetric problems
Sammanfattning : We study robust, preconditioned, iterative solution methods for large-scale linear systems of equations, arising from different applications in geophysics and geotechnics.The first type of linear systems studied here, which are dense, arise from a boundary element type of discretization of crack propagation in brittle material. LÄS MER