A spectral PRP conjugate gradient methods for nonconvex optimization problem based on modified line search

In this paper, a new spectral PRP conjugate gradient algorithm isdeveloped for solving nonconvex unconstrained optimization problems.The search direction in this algorithm is proved to be a sufficientdescent direction of the objective function independent of linesearch. To rule out possible unacceptably short step in the Armijoline search, a modified Armijo line search strategy is presented.The obtained step length is improved by employing the...