The combination of approximate solutions for accelerating the convergence
The General Neville-Aitken-Algorithm and Some Applications.
Two Composition Methods for Solving Certain Systems of Linear Equations.
Two step extrapolation and optimum choice of relaxation factor of the extrapolated S.O.R. method
Limits of the extrapolation coefficients are rational functions of several poles with the largest moduli of the resolvent operator and therefore good estimates of these poles could be calculated from these coefficients. The calculation is very easy for the case of two coefficients and its practical effect in finite dimensional space is considerable. The results are used for acceleration of S.O.R. method.