Search for dissertations about: "block iteration"

Showing result 1 - 5 of 16 swedish dissertations containing the words block iteration.

2. 1. On Numerical Solution Methods for Block-Structured Discrete Systems

   Author : Petia Boyanova; Maya Neytcheva; Oleg Iliev; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Preconditioning techniques; Finite element method; Two-by-two block matrices; Optimal order methods; AMLI method; Cahn-Hilliard equation; Multiphase flow; Inexact Newton method; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Abstract : 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. READ MORE

4. 2. Algebraic Reconstruction Methods

   Author : Touraj Nikazad; Tommy Elfving; Constantin Popa; Linköpings universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; iterative methods; image reconstruction; ART; Cimmino; Kaczmarz; Landweber; sequential iteration; simultaneous iteration; block iteration; semi-convergence; relaxation parameters; stopping rules; discrepancy principle; Numerical analysis; Numerisk analys;

   Abstract : Ill-posed sets of linear equations typically arise when discretizing certain types of integral transforms. A well known example is image reconstruction, which can be modeled using the Radon transform. After expanding the solution into a finite series of basis functions a large, sparse and ill-conditioned linear system occurs. READ MORE

5. 3. Robust preconditioned iterative solution methods for large-scale nonsymmetric problems

   Author : Erik Bängtsson; Maya Neytcheva; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Scientific Computing; Beräkningsvetenskap;

   Abstract : 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. READ MORE

6. 4. The Use of Landweber Algorithm in Image Reconstruction

   Author : Touraj Nikazad; Tommy Elfving; George Baravdish; Linköpings universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; convex feasibility; projection methods; simultaneous algorithms; iterative methods; stopping rules; semi-convergence; Numerical analysis; Numerisk analys;

   Abstract : Ill-posed sets of linear equations typically arise when discretizing certain types of integral transforms. A well known example is image reconstruction, which can be modelled using the Radon transform. After expanding the solution into a finite series of basis functions a large, sparse and ill-conditioned linear system arises. READ MORE

7. 5. Aspects of the recursive projection method applied to flow calculations

   Author : Joakim Möller; Jesper Oppelstrup; Per Weinerfelt; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Datorteknik; applied mechanics; computer science; aerospace; Datorteknik; Computer engineering; Datorteknik;

   Abstract : In this thesis, we have investigated the Recursive Projection Method, RPM, as an accelerator for computations of both steady and unsteady flows, and as a stabilizer in a bifurcation analysis.The criterion of basis extraction is discussed. READ MORE