Search for dissertations about: "Lanczos algorithm"

Showing result 1 - 5 of 10 swedish dissertations containing the words Lanczos algorithm.

  2. 1. Adaptive Solvers for High-Dimensional PDE Problems on Clusters of Multicore Processors

    Author : Magnus Grandin; Sverker Holmgren; Michael Thuné; Michael Bader; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; adaptive mesh refinement; anisotropic refinement; exponential integrators; Lanczos algorithm; hybrid parallelization; time-dependent Schrödinger equation; Scientific Computing; Beräkningsvetenskap;

    Abstract : Accurate numerical solution of time-dependent, high-dimensional partial differential equations (PDEs) usually requires efficient numerical techniques and massive-scale parallel computing. In this thesis, we implement and evaluate discretization schemes suited for PDEs of higher dimensionality, focusing on high order of accuracy and low computational cost. READ MORE

  4. 2. A Richardson Leja Lanczos algorithm to compute interior eigenvalues of very large matrices

    Author : Sonia Gupta; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : .... READ MORE

  5. 3. Subspace Computations via Matrix Decompositions and Geometric Optimization

    Author : Lennart Simonsson; Axel Ruhe; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Numerical Analysis; Rank-revealing UTV; Jacobi-Davidson algorithm; Decomposition; Grassmann type algorithms; Numerical analysis; Numerisk analys;

    Abstract : This thesis is concerned with the computation of certain subspaces connected to a given matrix, where the closely related problem of approximating the matrix with one of lower rank is given special attention. To determine the rank and obtain bases for fundamental subspaces such as the range and null space of a matrix, computing the singular value decomposition (SVD) is the standard method. READ MORE

  6. 4. Singular Value Computations for Toeplitz Matrices and Subspace Tracking

    Author : Eva Lundström; Henk van der Vorst; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : This thesis addresses the problem of computing the largest singular values and corresponding singular vectors of a Toeplitz matrix. These are often requested in signal processing and system identification to extract the signal from the noise. READ MORE

  7. 5. Experimental Studies of the Neutron Deficient Atomic Nuclei 88Ru and 87Tc, and the Diagonalization of the General Pairing Hamiltonian

    Author : Xiaoyu Liu; Bo Cederwall; Chong Qi; Jelena Vesic; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Atomic; Subatomic and Astrophysics; Atomär fysik; subatomär fysik och astrofysik;

    Abstract : This doctoral thesis consists of two parts: the experimental study of the neutron-deficient atomic nuclei 88Ru and 87Tc, and the computational study on the diagonalization of general pairing Hamiltonian. In the first part, which constitutes the main content of the thesis, the low-lying excited states in the N = Z nucleus 88Ru and N = Z + 1 nucleus 87Tc were studied via fusion-evaporation reactions induced by 115 MeV 36 Ar ions bombarding6 mg/cm 2 thick metallic 54 Fe target foils at the Grand Accélérateur Nationald’Ions Lourds (GANIL), Caen, France. READ MORE