Sharp estimates for the convergence rate of Orthomin(k) for a class of linear systems

Andrei Draganescu, Florin Spinu

In this work we show that the convergence rate of Orthomin($k$) applied to systems of the form $(I+\rho U)x=b$, where $U$ is a unitary operator and $0<\rho <1$, is less than or equal to…