Strong Wolfe-Powell Line Search Research Articles

Good Characteristics of The New Spectral Conjugate Gradient Method for Unconstrained Optimization

The spectral conjugate gradient (SCG) method is an effective method to solve large-scale nonlinear unconstrained optimization problems. In this work, we propose a new SCG method in which performance is numerically analyzed. We established the descent property and global convergence conditions based on assumptions through the strongWolfe-Powell line search. Numerical results were performed using benchmark functions widely used in many conventional functions to evaluate the efficiency of the proposed method.Subject Classification: 90C30, 90C06, 65K05, 65K10.

Global Convergence Condition for a New Spectral Conjugate Gradient Method for Large-Scale Optimization

The spectral conjugate gradient (SCG) method is an effective method to solve large-scale nonlinear unconstrained optimization problems. In this work, a new spectral conjugate gradient method is proposed with a strong Wolfe-Powell line search (SWP). The idea of the new one is using the βBZA formula which is proposed by Baluch and et al., with suitable parameter φ denoted by (SCGBZA). Under the usual assumptions, the descent properties and overall global convergence of the proposed method (SCGBZA) are proved. The proposed method is numerically proven to be effective.

An Efficient Modified AZPRP Conjugate Gradient Method for Large-Scale Unconstrained Optimization Problem

To find a solution of unconstrained optimization problems, we normally use a conjugate gradient (CG) method since it does not cost memory or storage of second derivative like Newton’s method or Broyden–Fletcher–Goldfarb–Shanno (BFGS) method. Recently, a new modification of Polak and Ribiere method was proposed with new restart condition to give a so-call AZPRP method. In this paper, we propose a new modification of AZPRP CG method to solve large-scale unconstrained optimization problems based on a modification of restart condition. The new parameter satisfies the descent property and the global convergence analysis with the strong Wolfe-Powell line search. The numerical results prove that the new CG method is strongly aggressive compared with CG_Descent method. The comparisons are made under a set of more than 140 standard functions from the CUTEst library. The comparison includes number of iterations and CPU time.

A conjugate gradient method for distributed optimal control problems with nonhomogeneous Helmholtz equation

A conjugate gradient algorithm with strong Wolfe-Powell line search for distributed optimal control problem is proposed. The optimal system has been discussed in [1]. The proposed algorithm is employed to solve the problem in infinite dimensional function space. With low complexity, it is suitable for large-scale problem. The sufficient descent condition of conjugate gradient and the existence of iterative step are proved. The algorithm also has global convergence property and linear convergence rate. At last, numerical experiments are presented to illustrate the efficiency and the convergence rate of the proposed algorithm.

An efficient modified PRP-FR hybrid conjugate gradient method for solving unconstrained optimization problems

In this paper, a new hybrid conjugate gradient method for solving unconstrained optimization problems is proposed. The proposed method inherits the features of the PRP, FR and NPRP conjugate gradient methods. The method satisfies the sufficient descent property independent of any line search and its global convergence is established under the strong Wolfe-Powell line search conditions. Numerical results show that the new algorithm is very competitive.

A Nonlinear Conjugate Gradient Algorithm under Strong Wolfe-Powell Line Search for Large Scale Unconstrained Optimization Problems

The conventional conjugate gradient method solves linear and quadratic optimization problems but most real life problems consist of nonquadratic functions of several variables. In this work a nonlinear conjugate gradient algorithm for solving large scale optimization problems is presented. The new algorithm is a modification of the Fletcher-Reeves conjugate gradient method and it is proved to achieve global convergence under the strong Wolfe-Powell inexact line search technique. Computational experiments show that the new algorithm presented performs better than the Fletcher-Reeves exact line search algorithm in solving high dimensional nonlinear optimization problems.

Global Convergence of a New Coefficient Nonlinear Conjugate Gradient Method

Nonlinear conjugate gradient (CG) methods are widely used in optimization field due to its efficiency for solving a large scale unconstrained optimization problems. Many studies and modifications have been developed in order to improve the method. The method is known to possess sufficient descend condition and its global convergence properties under strong Wolfe-Powell search direction. In this paper, the new coefficient of CG method is presented. The global convergence and sufficient descend properties of the new coefficient are established by using strong Wolfe-Powell line search direction. Results show that the new coefficient is able to globally converge under certain assumptions and theories.

Global convergence analysis of a new hybrid conjugate gradient method for unconstrained optimization problems

In this paper, we propose a new hybrid conjugate gradient method for unconstrained optimization problems. The proposed method comprises of beta (DY), beta (WHY), beta (RAMI) and beta (New). The beta (New) was constructed purposely for this proposed hybrid method.The method possesses sufficient descent property irrespective of the line search. Under Strong Wolfe-Powell line search, we proved that the method is globally convergent. Numerical experimentation shows the effectiveness and robustness of the proposed method when compare with some hybrid as well as some modified conjugate gradient methods.

An efficient modified Polak–Ribière–Polyak conjugate gradient method with global convergence properties

The conjugate gradient (CG) method is one of the most popular methods for solving large-scale unconstrained optimization problems. In this paper, a new modified version of the CG formula that was introduced by Polak, Ribière, and Polyak is proposed for problems that are bounded below and have a Lipschitz-continuous gradient. The new parameter provides global convergence properties when the strong Wolfe-Powell (SWP) line search or the weak Wolfe-Powell (WWP) line search is employed. A proof of a sufficient descent condition is provided for the SWP line search. Numerical comparisons between the proposed parameter and other recent CG modifications are made on a set of standard unconstrained optimization problems. The numerical results demonstrate the efficiency of the proposed CG parameter compared with the other CG parameters.

An efficient modification of the Hestenes-Stiefel nonlinear conjugate gradient method with restart property

The conjugate gradient (CG) method is one of the most popular methods to solve nonlinear unconstrained optimization problems. The Hestenes-Stiefel (HS) CG formula is considered one of the most efficient methods developed in this century. In addition, the HS coefficient is related to the conjugacy condition regardless of the line search method used. However, the HS parameter may not satisfy the global convergence properties of the CG method with the Wolfe-Powell line search if the descent condition is not satisfied. In this paper, we use the original HS CG formula with a mild condition to construct a CG method with restart using the negative gradient. The convergence and descent properties with the strong Wolfe-Powell (SWP) and weak Wolfe-Powell (WWP) line searches are established. Using this condition, we guarantee that the HS formula is non-negative, its value is restricted, and the number of restarts is not too high. Numerical computations with the SWP line search and some standard optimization problems demonstrate the robustness and efficiency of the new version of the CG parameter in comparison with the latest and classical CG formulas. An example is used to describe the benefit of using different initial points to obtain different solutions for multimodal optimization functions.

A conjugate gradient method with strong Wolfe-Powell line search for unconstrained optimization

In this paper, a modified conjugate gradient method is presented for solving large-scale unconstrained optimization problems, which possesses the sufficient descent property with Strong Wolfe-Powell line search. A global convergence result was proved when the (SWP) line search was used under some conditions. Computational results for a set consisting of 138 unconstrained optimization test problems showed that this new conjugate gradient algorithm seems to converge more stable and is superior to other similar methods in many situations.

An Efficient Hybrid Conjugate Gradient Method with the Strong Wolfe-Powell Line Search

Conjugate gradient (CG) method is an interesting tool to solve optimization problems in many fields, such as design, economics, physics, and engineering. In this paper, we depict a new hybrid of CG method which relates to the famous Polak-Ribière-Polyak (PRP) formula. It reveals a solution for the PRP case which is not globally convergent with the strong Wolfe-Powell (SWP) line search. The new formula possesses the sufficient descent condition and the global convergent properties. In addition, we further explained about the cases where PRP method failed with SWP line search. Furthermore, we provide numerical computations for the new hybrid CG method which is almost better than other related PRP formulas in both the number of iterations and the CPU time under some standard test functions.

A Modified Conjugacy Condition and Related Nonlinear Conjugate Gradient Method

The conjugate gradient (CG) method has played a special role in solving large-scale nonlinear optimization problems due to the simplicity of their very low memory requirements. In this paper, we propose a new conjugacy condition which is similar to Dai-Liao (2001). Based on this condition, the related nonlinear conjugate gradient method is given. With some mild conditions, the given method is globally convergent under the strong Wolfe-Powell line search for general functions. The numerical experiments show that the proposed method is very robust and efficient.

A Conjugate Gradient Method for Unconstrained Optimization Problems

A hybrid method combining the FR conjugate gradient method and the WYL conjugate gradient method is proposed for unconstrained optimization problems. The presented method possesses the sufficient descent property under the strong Wolfe-Powell (SWP) line search rule relaxing the parameterσ<1. Under the suitable conditions, the global convergence with the SWP line search rule and the weak Wolfe-Powell (WWP) line search rule is established for nonconvex function. Numerical results show that this method is better than the FR method and the WYL method.

The proof of the sufficient descent condition of the Wei–Yao–Liu conjugate gradient method under the strong Wolfe–Powell line search

Abstract In [Z. Wei et al., The convergence properties of some conjugate gradient methods, Appl. Math. Comput. 183 (2006) 1341–1350], Wei et al. proposed a new conjugate gradient method called WYL method which has good numerical experiments. Under the sufficient descent condition and WWP line search, the given method’s convergent results have been established by Wei et al. So, the sufficient descent condition is important for the WYL method. In this paper, we prove that, by restricting the parameter σ 1 4 , under the SWP line search condition, the WYL method possess the sufficient descent condition which deduces the global convergent results of the WYL method under SWP line search.