Derivative-Free Optimal Iterative Methods

Abstract In this study, we develop an optimal family of derivative-free iterative methods. Convergence analysis shows that the methods are fourth order convergent, which is also verified numerically. The methods require three functional evaluations during each iteration. Though the methods are independent of derivatives, computa- tional results demonstrate that the family of methods are efficient and demonstrate equal or better performance as compared with many well-known methods and the clas- sical Newton method. Through optimization we derive an optimal value for the free parameter and implement it adaptively, which enhances the convergence order without increasing functional evaluations.