Search for dissertations about: "method of conjugate gradients"

Showing result 1 - 5 of 7 swedish dissertations containing the words method of conjugate gradients.

  2. 1. On Methods for Solving Symmetric Systems of Linear Equations Arising in Optimization

    Author : Tove Odland; Anders Forsgren; William W. Hager; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; symmetric system of linear equations; method of conjugate gradients; quasi-Newton method; unconstrained optimization; unconstrained quadratic optimiza- tion; Krylov subspace method; unnormalized Lanczos vectors; minimum-residual method; symmetriska linjära ekvationssystem; konjugerade gradientmetoden; kvasi- Newtonmetoder; optimering utan bivillkor; kvadratisk optimering utan bivillkor; Kry- lovunderrumsmetoder; icke-normaliserade Lanczosvektorer; minimum-residualmetoden; Mathematics; Matematik;

    Abstract : In this thesis we present research on mathematical properties of methods for solv- ing symmetric systems of linear equations that arise in various optimization problem formulations and in methods for solving such problems.In the first and third paper (Paper A and Paper C), we consider the connection be- tween the method of conjugate gradients and quasi-Newton methods on strictly convex quadratic optimization problems or equivalently on a symmetric system of linear equa- tions with a positive definite matrix. READ MORE

  4. 2. Parallelizing the Method of Conjugate Gradients for Shared Memory Architectures

    Author : Henrik Löf; Jarmo Rantakokko; Erik Hagersten; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Beräkningsvetenskap; Scientific Computing;

    Abstract : Solving Partial Differential Equations (PDEs) is an important problem in many fields of science and engineering. For most real-world problems modeled by PDEs, we can only approximate the solution using numerical methods. Many of these numerical methods result in very large systems of linear equations. READ MORE

  5. 3. Approaches to accelerate methods for solving systems of equations arising in nonlinear optimization

    Author : David Ek; Anders Forsgren; Jacek Gondzio; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Nonlinear optimization; mathematical programming; interior-point methods; approximate solutions to systems of linear equations; method of conjugate gradients; quasi-Newton methods; modified Newton methods; Ickelinjär optimering; matematisk programmering; inre-punktsmetoder; approximativa lösningar till linjära ekvationssystem; konjugerade gradientmetoden; kvasi-Newtonmetoder; modifierade Newtonmetoder.; Optimization and Systems Theory; Optimeringslära och systemteori;

    Abstract : Methods for solving nonlinear optimization problems typically involve solving systems of equations. This thesis concerns approaches for accelerating some of those methods. In our setting, accelerating involves finding a trade-off between the computational cost of an iteration and the quality of the computed search direction. READ MORE

  6. 4. Iterative and Adaptive PDE Solvers for Shared Memory Architectures

    Author : Henrik Löf; Jarmo Rantakokko; Sverker Holmgren; Erik Hagersten; Mark Bull; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; partial differential equations; iterative methods; finite elements; conjugate gradients; adaptive mesh refinement; multigrid; cc-NUMA; distributed shared memory; OpenMP; page migration; TLB shoot-down; bandwidth minimization; reverse Cuthill-McKee; migrate-on-next-touch; affinity; temporal locality; chip multiprocessors; CMP; Beräkningsvetenskap; Scientific Computing;

    Abstract : Scientific computing is used frequently in an increasing number of disciplines to accelerate scientific discovery. Many such computing problems involve the numerical solution of partial differential equations (PDE). READ MORE

  7. 5. Three-dimensional forward modelling and inversion of controlled-source electromagnetic data using the edge-based finite-element method

    Author : Paula Rulff; Thomas Kalscheuer; Michael Becken; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Applied geophysics; Controlled-source electromagnetics; Numerical modelling; Finite-element method; Geophysical inversion; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

    Abstract : Electromagnetic geophysical methods are applied to investigate anomalous subsurface structures exhibiting contrasts in electrical resistivity, as for example in mineral exploration or geothermal areas. When evaluating electromagnetic data, one big challenge is to account for full three-dimensional measurement setups and subsurface scenarios. READ MORE