Semidiscrete least-squares methods for a parabolic boundary value problem

Semidiscrete-Least Squares Methods for a Parabolic Boundary Value Problem

In this paper some approximate methods for solving the initial-boundary value problem for the heat equation in a cylinder under homogeneous boundary conditions are analyzed. The methods consist in discretizing with respect to time and solving approximately the resulting elliptic problem for fixed time by least squares methods. The approximate solutions will belong to a finite-dimensional subspa...

Wavelet Least Squares Methods for Boundary Value Problems

Multilevel Boundary Functionals for Least-squares Mixed Finite Element Methods

For least-squares mixed nite element methods for the rst-order system formulation of second-order elliptic problems, a technique for the weak enforcement of boundary conditions is presented. This approach is based on least-squares boundary functionals which are equivalent to the H ?1=2 and H 1=2 norms on the trace spaces of lowest-order Raviart-Thomas elements for the ux and standard continuous...

Computational Investigations of Least-Squares Type Methods for the Approximate Solution of Boundary Value Problems

Several Galerkin schemes for approximate solution of linear elliptic boundary value problems are studied for such computational aspects as obtainable accuracy, sensitivity to parameters and conditioning of linear systems. Methods studied involve computing subspaces (e.g., splines) whose elements need not satisfy boundary conditions. A Poisson problem study on the square produces computed error ...

Harmonic and refined extraction methods for the singular value problem, with applications in least squares problems

For the accurate approximation of the minimal singular triple (singular value and left and right singular vector), we may use two separate search spaces, one for the left, and one for the right singular vector. In Lanczos bidiagonalization, for example, such search spaces are constructed. In [3], the author proposes a Jacobi–Davidson type method for the singular value problem, where solutions t...