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Visar resultat 1 - 5 av 11 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Parallelization of dynamic algorithms for electronic structure calculations

   Författare :Anton G. Artemov; Emanuel H. Rubensson; Maya Neytcheva; Bo Kågström; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; parallelization; task-based programming; matrix algorithms; sparse matrices; inverse factorization; localized computations; density matrix methods; electronic structure calculations; Scientific Computing; Beräkningsvetenskap;

   Sammanfattning : The aim of electronic structure calculations is to simulate behavior of complex materials by resolving interactions between electrons and nuclei in atoms at the level of quantum mechanics. Progress in the field allows to reduce the computational complexity of the solution methods to linear so that the computational time scales proportionally to the size of the physical system. LÄS MER

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

   Författare :Petia Boyanova; Maya Neytcheva; Oleg Iliev; Uppsala universitet; []
   Nyckelord :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;

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

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

   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

5. 4. Robust Preconditioners Based on the Finite Element Framework

   Författare :Erik Bängtsson; Maya Neytcheva; Per Lötstedt; Svetozar Margenov; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; FEM; iterative solution method; algebraic multilevel preconditioner; sparse approximate inverse; block preconditioner; Schur complement approximation; nonsymmetric saddle point matrix; isostatic glacial adjustment; pre-stress advection; elasticity; viscoelasticity; in compressible solid; ABAQUS; BEM DDM; Scientific Computing; Beräkningsvetenskap;

   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

7. 5. Numerical Approximation of Reaction and Diffusion Systems in Complex Cell Geometry

   Författare :Qasim Ali Chaudhry; Michael Hanke; Maya Gueorguieva Neytcheva; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Complex Cell Geometry; Reaction and Diffusion System; Metabolism in Biological Cells; Homogenization; Compartment Modelling; Numerical analysis; Numerisk analys;

   Sammanfattning : The mathematical modelling of the reaction and diffusion mechanism of lipophilic toxic compounds in the mammalian cell is a challenging task because of its considerable complexity and variation in the architecture of the cell. The heterogeneity of the cell regarding the enzyme distribution participating in the bio-transformation, makes the modelling even more difficult. LÄS MER