An Iteration Function Having Optimal Eighth-Order of Convergence for Multiple Roots and Local Convergence

Local Convergence of an Optimal Eighth Order Method under Weak Conditions

We study the local convergence of an eighth order Newton-like method to approximate a locally-unique solution of a nonlinear equation. Earlier studies, such as Chen et al. (2015) show convergence under hypotheses on the seventh derivative or even higher, although only the first derivative and the divided difference appear in these methods. The convergence in this study is shown under hypotheses...

Three-step iterative methods with optimal eighth-order convergence

In this paper, based on Ostrowski’s method, a new family of eighth-order methods for solving nonlinear equations is derived. In terms of computational cost, each iteration of these methods requires three evaluations of the function and one evaluation of its first derivative, so that their efficiency indices are 1.682, which is optimal according to Kung and Traub’s conjecture. Numerical comparis...

First-Order Convergence and Roots

Nešetřil and Ossona de Mendez introduced the notion of first order convergence, which unifies the notions of convergence for sparse and dense graphs. They asked whether if (Gi)i∈N is a sequence of graphs with M being their first order limit and v is a vertex of M , then there exists a sequence (vi)i∈N of vertices such that the graphs Gi rooted at vi converge to M rooted at v. We show that this ...

Convergence of an Implicit Iteration for Affine Mappings in Normed and Banach Spaces

An efficient family of weighted-Newton methods with optimal eighth order convergence

Based on Newton’s method, we present a family of three-point iterative methods for solving nonlinear equations. In terms of computational cost, the family requires four function evaluations and has convergence order eight. Therefore, it is optimal in the sense of Kung–Traubhypothesis andhas the efficiency index1.682which is better than that ofNewton’s and many other higher order methods. Some n...