Search for dissertations about: "preconditioned iterative method"

Showing result 1 - 5 of 14 swedish dissertations containing the words preconditioned iterative method.

  2. 1. Domain Decomposition and Preconditioned Iterative Methods for the Helmholtz Equation

    Author : Elisabeth Larsson; Kurt Otto; Bengt Fornberg; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Helmholtz equation; domain decomposition; preconditioned iterative method; fast transforms; parallelization; Numerical Analysis; Numerisk analys;

    Abstract : New preconditioned iterative solution methods for the Helmholtz equation are constructed. To evaluate the performance of the methods, two-dimensional problems with a waveguide geometry are used as model problems. Second- and fourth-order accurate finite difference discretizations are used. READ MORE

  4. 2. Implementation of the spectral element method and iterative solution techniques for 3D controlled-source electromagnetic modelling

    Author : Michael Weiss; Thomas Kalscheuer; Michael Becken; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Controlled source electromagnetis; Electromagnetic theory; Numerical modelling; Applied geophysics; Geo-Electromagnetics; Spectral element method; Iterative solution methods; Preconditioning;

    Abstract : Controlled-source electromagnetic methods are imaging techniques applied at/on the surface of the Earth which record the electromagnetic field in order to assess the electrical conductivity distribution of the Earth’s subsurface, along with anomalies in this material property, as well as to characterise and interpret structures in Earth’s crust. Extracting information from the recorded electromagnetic data requires inverse modelling algorithms. 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. Computational Solid Wave Propagation Numerical Techniques and Industrial Applications

    Author : Torbjörn Ekevid; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wave propagation; multigrid; adaptivity; parallel; FEM; iterative; SBFEM;

    Abstract : For wave propagation and many other physical phenomena, the dynamic effects are vital. In industrial applications, such problems are very complex and generally have to be treated by means of numerical methods. READ MORE

  7. 5. Developments in preconditioned iterative methods with application to glacial isostatic adjustment models

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

    Abstract : This study examines the block lower-triangular preconditioner with element-wise Schur complement as the lower diagonal block applied on matrices arising from an application in geophysics. The element-wise Schur complement is a special approximation of the exact Schur complement that can be constructed in the finite element framework. READ MORE