An adaptive Chebyshev iterative method for nonsymmetric linear systems based on modified moments (Q1326468)

Three term recurrence relations in the Krylov space are considered when a linear system of equations with a nonsymmetric matrix \(A\) is to be solved. If the spectrum of \(A\) lies in an ellipse whose width is small, when compared with its distance from the origin, relations with fixed parameters may be used. Otherwise adaptive coefficients which depend on some modified moments are recommended. The connection with the nonsymmetric Lanczos method is discussed.