Approximate root-free factorization techniques for solving elliptic difference equations in three spaces variables

AbstractExtended-to-the-limit sparse root-free factorization procedures are introduced for solving large sparse symmetric structured linear systems of algebraic equations, which are derived from the finite-difference discretization of self-adjoint elliptic PDEs in three space dimensions. Theoretical results on the rate of convergence of relevant approximate matrix-factorization semidirect methods for three space variables are also presented