On a cubically convergent iterative method for matrix sign.

We propose an iterative method for finding matrix sign function. It is shown that the scheme has global behavior with cubical rate of convergence. Examples are included to show the applicability and efficiency of the proposed scheme and its reciprocal.

On a derivative-free variant of king's family with memory.

The aim of this paper is to construct a method with memory according to King's family of methods without memory for nonlinear equations. It is proved that the proposed method possesses higher R-order of convergence using the same number of functional evaluations as King's family. Numerical experiments are given to illustrate the performance of the constructed scheme.