Two Modified Polak–Ribière–Polyak-Type Nonlinear Conjugate Methods with Sufficient Descent Property

In this article, we propose a new conjugate gradient type formula for computing unconstrained optimization problems. Its form is similar to the original PRP formula and it inherits all nice properties of the PRP method. By utilizing the technique of the three-term PRP method in Zhang [Citation20] and modified PRP method in Yu [Citation17], we propose two modified methods of the new formula. The two modified methods all can generate sufficient...