39 research outputs found

    Fast algorithms for integral equations.

    Get PDF
    by Wing-Fai Ng.Thesis (M.Phil.)--Chinese University of Hong Kong, 1996.Includes bibliographical references (leaves 7-8).Abstract --- p.1-2Introduction --- p.3-6References --- p.7-8Paper I --- p.9-32Paper II --- p.33-6

    Fast algorithm for ill-conditioned toeplitz and toeplitz-like systems.

    Get PDF
    by Hai-Wei Sun.Thesis (Ph.D.)--Chinese University of Hong Kong, 1996.Includes bibliographical references.Abstracts --- p.1Summary --- p.3Introduction --- p.3Summary of the papers A-C --- p.5Paper A --- p.19Paper B --- p.34Paper C --- p.6

    A fast and well-conditioned spectral method for singular integral equations

    Get PDF
    We develop a spectral method for solving univariate singular integral equations over unions of intervals by utilizing Chebyshev and ultraspherical polynomials to reformulate the equations as almost-banded infinite-dimensional systems. This is accomplished by utilizing low rank approximations for sparse representations of the bivariate kernels. The resulting system can be solved in O(m2n){\cal O}(m^2n) operations using an adaptive QR factorization, where mm is the bandwidth and nn is the optimal number of unknowns needed to resolve the true solution. The complexity is reduced to O(mn){\cal O}(m n) operations by pre-caching the QR factorization when the same operator is used for multiple right-hand sides. Stability is proved by showing that the resulting linear operator can be diagonally preconditioned to be a compact perturbation of the identity. Applications considered include the Faraday cage, and acoustic scattering for the Helmholtz and gravity Helmholtz equations, including spectrally accurate numerical evaluation of the far- and near-field solution. The Julia software package SingularIntegralEquations.jl implements our method with a convenient, user-friendly interface

    Fast Numerical Methods for Non-local Operators

    Get PDF
    [no abstract available

    Fast numerical methods for non-local operators

    Full text link

    Numerical solution of integral equation of the second kind.

    Get PDF
    by Chi-Fai Chan.Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.Includes bibliographical references (leaves 53-54).Abstract also in Chinese.Chapter Chapter 1 --- INTRODUCTION --- p.1Chapter §1.1 --- Polynomial Interpolation --- p.1Chapter §1.2 --- Conjugate Gradient Type Methods --- p.6Chapter §1.3 --- Outline of the Thesis --- p.10Chapter Chapter 2 --- INTEGRAL EQUATIONS --- p.11Chapter §2.1 --- Integral Equations --- p.11Chapter §2.2 --- Numerical Treatments of Second Kind Integral Equations --- p.15Chapter Chapter 3 --- FAST ALGORITHM FOR SECOND KIND INTEGRAL EQUATIONS --- p.20Chapter §3.1 --- Introduction --- p.20Chapter §3.2 --- The Approximation --- p.24Chapter §3.3 --- Error Analysis --- p.35Chapter §3.4 --- Numerical Examples --- p.40Chapter §3.5 --- Concluding Remarks --- p.51References --- p.5

    Some fast algorithms in signal and image processing.

    Get PDF
    Kwok-po Ng.Thesis (Ph.D.)--Chinese University of Hong Kong, 1995.Includes bibliographical references (leaves 138-139).AbstractsSummaryIntroduction --- p.1Summary of the papers A-F --- p.2Paper A --- p.15Paper B --- p.36Paper C --- p.63Paper D --- p.87Paper E --- p.109Paper F --- p.12
    corecore