Three-level extrapolated alternating direction implicit (E.A.D.I.) methods for the numerical solution of two-dimensional second order elliptic problems

This paper extends the theory concerning the three-level E.A.D.I. schemes to cover the numerical solution of more general (than the trivial first boundary value problem for Poisson's equation in a square) two-dimensional second order elliptic problems. Moreover numerical examples proving the validity of the theory developed are presented and general conclusions are drawn.