Sökning: "Saddle point matrix"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden Saddle point matrix.

  1. 1. Exact Results in Five-Dimensional Gauge Theories : On Supersymmetry, Localization and Matrix Models

    Författare :Anton Nedelin; Joseph Minahan; Ivan Kostov; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Supersymmetric localization; Matrix Models; Chern-Simons theory; Supersymmetric Field Theories; 2; 0 theories; Theoretical Physics; Teoretisk fysik;

    Sammanfattning : Gauge theories are one of the corner stones of modern theoretical physics. They describe the nature of all fundamental interactions and have been applied in multiple branches of physics. The most challenging problem of gauge theories, which has not been solved yet, is their strong coupling dynamics. LÄS MER

  3. 2. Analysis and Implementation of Preconditioners for Prestressed Elasticity Problems : Advances and Enhancements

    Författare :Ali Dorostkar; Maya Neytcheva; Thomas Huckle; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; FEM; Saddle point matrix; Preconditioning; Schur complement; Generalized Locally Toeplitz; Prestressed elasticity; Scientific Computing; Beräkningsvetenskap;

    Sammanfattning : In this work, prestressed elasticity problem as a model of the so-called glacial isostatic adjustment (GIA) process is studied. The model problem is described by a set of partial differential equations (PDE) and discretized with a mixed finite element (FE) formulation. LÄS MER

  4. 3. 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

  5. 4. Computational Techniques for Coupled Flow-Transport Problems

    Författare :Martin Kronbichler; Gunilla Kreiss; Jean-Luc Guermond; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Finite element method; saddle point systems; two-phase flow; level set method; phase field method; stabilization; contact line dynamics; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : This thesis presents numerical techniques for solving problems of incompressible flow coupled to scalar transport equations using finite element discretizations in space. The two applications considered in this thesis are multi-phase flow, modeled by level set or phase field methods, and planetary mantle convection based on the Boussinesq approximation. LÄS MER

  7. 5. Robust preconditioning methods for algebraic problems, arising in multi-phase flow models

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

    Sammanfattning : The aim of the project is to construct, analyse and implement fast and reliable numerical solution methods to simulate multi-phase flow, modeled by a coupled system consisting of the time-dependent Cahn-Hilliard and incompressible Navier-Stokes equations with variable viscosity and variable density. This thesis mainly discusses the efficient solution methods for the latter equations aiming at constructing preconditioners, which are numerically and computationally efficient, and robust with respect to various problem, discretization and method parameters. LÄS MER