Abstract
IDR(s)-R2 method based on the IDR Theorem have been proposed. On the other hand, computational cost reduction method by Slim Dense matrix P have been proposed. however, Slim Dense matrix P has possibility of becoming unstable because of majority of the element is assumed to be 0. Therefore, in this paper, we propose a device for building up a dense matrix P which is applicable commonly to a family of IDR(s) methods. Through numerical experiments, we clarify that the convergence of preconditioned IDR(s)-R2 method with the proposed structural of matrices P.
