  This paper is a continuation to the study of generalized quasi contractive
operators, essentially due to Akhtar et al. [A multi-step implicit iterative
process for common fixed points of generalized C^{q}-operators in convex metric
spaces, Sci. Int., 25(4) (2013), 887-891], in spaces of nonpositive sectional
curvature. We aim to establish results concerning convergence characteristics
of the classical iterative algorithms such as Picard, Mann, Ishikawa and
Xu-Noor iterative algorithms associated with the proposed class of generalized
quasi contractive operators. Moreover, we adopt the concept introduced by
Berinde [Comparing Krasnosel'skii and Mann iterative methods for Lipschitzian
generalized pseudo-contractions, Int. Conference on Fixed Point Theory Appl.,
15-26, Yokohama Publ., Yokohama, 2004.] for a comparison of the corresponding
rates of convergence of these iterative algorithms in such setting of spaces.
The results presented in this paper improve and extend some recent
corresponding results in the literature.
