On the Convergence Rate of Symmetric Single-Step Method ISS for Simultaneous Bounding Polynomial Zeros

A new modified method ISS for the simultaneous bounding all the zeros of a polynomial is formulated in this paper. The efficiency of this method is measured on the CPU times and the number of iterations after satisfying the convergence criteria where the results are obtained using five tested polynomials. The R-order of convergence of this method is at least 9.