Computational and Applied Mathematics 2020 39:38
https://doi.org/10.1007/s40314-019-1014-2
A unified algorithm for solving variational inequality
and fixed point problems with application to the split
equality problem
L. O. Jolaoso
1
· A. Taiwo
1
· T. O. Alakoya
1
· O. T. Mewomo
1
Received: 3 May 2019 / Revised: 16 October 2019 / Accepted: 14 November 2019
© SBMAC - Sociedade Brasileira de Matemática Aplicada e Computacional 2019
Abstract
In this paper, we propose a new extragradient method consisting of the hybrid steepest
descent method, a single projection method and an Armijo line searching the technique
for approximating a solution of variational inequality problem and finding the fixed point of
demicontractive mapping in a real Hilbert space. The essence of this algorithm is that a single
projection is required in each iteration and the step size for the next iterate is determined in
such a way that there is no need for a prior estimate of the Lipschitz constant of the underlying
operator. We state and prove a strong convergence theorem for approximating common
solutions of variational inequality and fixed points problem under some mild conditions on
the control sequences. By casting the problem into an equivalent problem in a suitable product
space, we are able to present a simultaneous algorithm for solving the split equality problem
without prior knowledge of the operator norm. Finally, we give some numerical examples to
show the efficiency of our algorithm over some other algorithms in the literature.
Keywords Variational inequality · Extragradient method · Split equality problem ·
Hyrbid-steepest descent · Armijo line search
Mathematics Subject Classification 65K15 · 47J25 · 65J15 · 90C33
Communicated by Pablo Pedregal.
B O. T. Mewomo
mewomoo@ukzn.ac.za
L. O. Jolaoso
216074984@stu.ukzn.ac.za; lateefjolaoso89@gmail.com
A. Taiwo
218086816@stu.ukzn.ac.za
T. O. Alakoya
218086823@stu.ukzn.ac.za; timimaths@gmail.com
1
School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban,
South Africa
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