Research Article
A Modified Scaled Spectral-Conjugate Gradient-Based
Algorithm for Solving Monotone Operator Equations
Auwal Bala Abubakar ,
1,2
Kanikar Muangchoo ,
3
Abdulkarim Hassan Ibrahim ,
4
SundayEmmanuelFadugba ,
5
KazeemOlalekanAremu ,
2,6
andLateefOlakunleJolaoso
2
1
Department of Mathematical Sciences, Faculty of Physical Sciences, Bayero University, Kano, Kano, Nigeria
2
Department of Mathematics and Applied Mathematics, Sefako Makgatho Health Sciences University, Ga-Rankuwa,
Pretoria 0204, South Africa
3
Faculty of Science and Technology, Rajamangala University of Technology Phra Nakhon (RMUTP),
1381, Pracharat 1 Road, Wongsawang, Bang Sue, Bangkok 10800, ailand
4
KMUTT Fixed Point Research Laboratory, Room SCL 802 Fixed Point Laboratory, Science Laboratory Building,
Department of Mathematics, Faculty of Science, King Mongkut’s University of Technology onburi (KMUTT),
126 Pracha-Uthit Road, Bang Mod, rung Khru, Bangkok 10140, ailand
5
Department of Mathematics, Ekiti State University, Ado Ekiti 360001, Nigeria
6
Department of Mathematics, Faculty of Science, Usmanu Danfodio University Sokoto, Sokoto, Nigeria
Correspondence should be addressed to Kanikar Muangchoo; kanikar.m@rmutp.ac.th
Received 13 January 2021; Revised 11 April 2021; Accepted 13 April 2021; Published 26 April 2021
Academic Editor: Jen-Chih Yao
Copyright © 2021 Auwal Bala Abubakar et al. is is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
is paper proposes a modified scaled spectral-conjugate-based algorithm for finding solutions to monotone operator equations.
e algorithm is a modification of the work of Li and Zheng in the sense that the uniformly monotone assumption on the operator
is relaxed to just monotone. Furthermore, unlike the work of Li and Zheng, the search directions of the proposed algorithm are
shown to be descent and bounded independent of the monotonicity assumption. Moreover, the global convergence is established
under some appropriate assumptions. Finally, numerical examples on some test problems are provided to show the efficiency of
the proposed algorithm compared to that of Li and Zheng.
1. Introduction
We desire in this work to propose an algorithm to solve the
problem:
F(x)� 0, x ∈ C, (1)
where F: R
n
⟶ R
n
is monotone and Lipschitz continuous
and C ⊆ R
n
is nonempty, closed, and convex.
Solving problems of form (1) are becoming interesting in
recent years due to its appearance in many areas of science,
engineering, and economy, for example, in forecasting of
financial market [1], constrained neural networks [2], eco-
nomic and chemical equilibrium problems [3, 4], signal and
image processing [5, 6], phase retrieval [7, 8], power flow
equations [9], nonnegative matrix factorisation [10, 11], and
many more.
Some notable methods for finding solution to (1) are:
Newton’s method, quasi-Newton method, Gauss–Newton
method, Levenberg–Marquardt method, and their vari-
ants [12–15]. ese methods are prominent due to their
fast convergence property. However, their convergence is
local, and they require computing and storing of the
Jacobian matrix at each iteration. In addition, there is a
need to solve a linear equation at each iteration. ese and
other reasons make them unattractive especially for large-
scale problems. To avoid the above drawbacks, methods
that are globally convergent and also do not require
computing and storing of the Jacobian matrix were
Hindawi
Journal of Mathematics
Volume 2021, Article ID 5549878, 9 pages
https://doi.org/10.1155/2021/5549878