The generalized superoptimal preconditioner
The authors study the preconditioner \(t_{F}(A)\) introduced by \textit{E. Tyrtyshnikov} [SIAM J. Matrix Anal. Appl. 13, No.~2, 459--473 (1992; Zbl 0774.65024)] in a general case by using the Moore-Penrose inverse. The paper also provides a spectral relation between the optimal and superoptimal preconditioned matrices in the general case.
scientific article; zbMATH DE number 5650031
scientific article