In this paper, we represent an inexact inverse subspace iteration method for computing a few eigenpairs of the generalized eigenvalue problem Ax = Bx [Q. Ye and P. Zhang, Inexact inverse subspace iteration for generalized eigenvalue problems, Linear Algebra and its Application, 434 (2011) 1697-1715 ]. In particular, the linear convergence property of the inverse subspace iteration is preserved.

In this paper we investigate the regularization properties of semiiterative regularization methods in Hilbert scales for linear ill-posed problems and perturbed data. It is well known that Landweber iteration can be remarkably accelerated by polynomial acceleration methods leading to the notion of optimal speed of convergence, which can be obtained by several efficient two-step methods, e.g., t...