A hybrid CG algorithm for nonlinear unconstrained optimization with application in image restoration

This paper presents a new hybrid conjugate gradient method for solving  nonlinear unconstrained optimization problems; it is based on a combination of RMIL  (Rivaie-Mustafa-Ismail-Leong)  and hSM  (hybrid Sulaiman- Mohammed) methods. The proposed algorithm enjoys the sufficient descent condition without depending on any line search; moreover, it is globally convergent under the usual and strong Wolfe line search assumptions.  The performance of the algorithm is demonstrated through numerical experiments on a set of ۱۰۰ test functions from [۱] and four image restoration problems with two noise levels. The numerical comparisons with four existing methods show that the proposed method is promising and effective.

Keywords:

Unconstrained optimization , Hybrid conjugate gradient , Global convergence , Image restoration