Sökning: "Krylov methods"

Visar resultat 6 - 10 av 23 avhandlingar innehållade orden Krylov methods.

1. 6. Information Retrieval Using Krylov Subspace Methods

   Författare :Katarina Blom; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : In this dissertation we discuss how simple Krylov subspace methods can be used for information retrieval (IR). The dissertation consists of two parts. The first part gives a background of IR and introduces the vector space model for IR and the Krylov subspace methods that we use. The second part consists of four articles. LÄS MER

3. 7. Krylov methods for nonlinear eigenvalue problems and matrix equations

   Författare :Giampaolo Mele; Elias Jarlebring; Raf Vandebril; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical Analysis; Numerisk analys;

   Sammanfattning : Nonlinear eigenvalue problems (NEPs) arise in many fields of science and engineering. Such problems are often defined by large matrices, which have specific structures, such as being sparse, low-rank, etc. Like the linear eigenvalue problem, the eigenvector appears in a linear form, whereas the eigenvalue appears in a nonlinear form. LÄS MER

4. 8. Parameter-free Krylov subspace iteration methods for the Euler and Navier–Stokes equations

   Författare :Karl Hörnell; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical Analysis; Numerisk analys;

   Sammanfattning : .... LÄS MER

5. 9. On Methods for Solving Symmetric Systems of Linear Equations Arising in Optimization

   Författare :Tove Odland; Anders Forsgren; William W. Hager; KTH; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

7. 10. Efficient Solvers for Space-Time Discontinuous Galerkin Spectral Element Methods

   Författare :Lea Miko Versbach; Numerisk analys; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Discontinuous Galerkin Method; Spectral Element Method; Finite Volume Method; Implicit Schemes; Preconditioner; Multigrid Method; Space-Time; Lobatto IIIC Method; Local Fourier Analysis;

   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