In this paper, a family of hybrid conjugate parameters with restart procedure is proposed. In which, we design a hybrid conjugate parameter by using two hybrid techniques, and set a restart procedure in its search dir...
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In this paper, a family of hybrid conjugate parameters with restart procedure is proposed. In which, we design a hybrid conjugate parameter by using two hybrid techniques, and set a restart procedure in its search direction according to the conjugate parameter. Under the usual assumptions and the weak Wolfe line search, we prove its sufficient descent property and global convergence. Finally, we choose a specific algorithm from this family and use an acceleration scheme to solve the large-scale unconstrained optimization problems and image restorations. These numerical results show that our algorithm is effective.
Conjugate Gradient (CG) methods are renowned for their efficiency and low memory requirements when solving optimization problems. However, certain formulations of CG methods that switch between two or more CG paramete...
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Conjugate Gradient (CG) methods are renowned for their efficiency and low memory requirements when solving optimization problems. However, certain formulations of CG methods that switch between two or more CG parameters often overlook specific values that could have been integrated. Moreover, the demonstration of the sufficient descent property in these methods usually relies on a strategy that assumes the possible exclusion of certain function values. To alleviate this assumption, this article introduces a structured Liu-Storey spectral CG method. This method extends the formulation of the spectral Fletcher conjugate descent method, enabling it to maintain fast convergence and inherit a good restart property. Therefore, the method ensures that the sufficient descent property holds without additional requirements and converges globally via some standard assumptions. Additionally, the method proves useful in solving robotic and image reconstruction models. Finally, it demonstrates robustness when compared to some standard algorithms.
The problem of collision detection plays an important role in many fields of science and engineering. This article presents a collision detection method for general convex objects bounded by pieces of implicit surface...
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The problem of collision detection plays an important role in many fields of science and engineering. This article presents a collision detection method for general convex objects bounded by pieces of implicit surfaces. There are two key ideas that underlie our method: one is the introduction of a new kind of pseudodistance, called the $\delta$-distance, for implicitly represented convex objects which has the desired properties of convexity and square differentiability;the other is the use of delta-distance functions to construct a virtual potential field in the real space, so that the problem of collision detection can be reduced to a problem of unconstrained convex optimization. The method is extended and applied to detect whether two objects collide when they are moving continuously along linearly translational trajectories, which is a special case of one of the continuous collision detection subproblems. We have implemented collision detection algorithms in C++ and conducted a large number of experiments, with test examples involving objects modeled by planar, quadric, superquadric, superellipsoidal, and hyperquadric surfaces, as well as pieces of them, in both stationary and linearly translational moving states. The experimental results show that our method has good performance and it is computationally efficient and widely applicable.
This paper deals with the adaptive trust region method with non-monotone line search. We first present a new inexact non-monotone line search and then apply it to the adaptive trust region framework. This method uses ...
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This paper deals with the adaptive trust region method with non-monotone line search. We first present a new inexact non-monotone line search and then apply it to the adaptive trust region framework. This method uses the advantage of the line search and non-monotone technique to increase the probability of acceptance of the trial step. The new algorithm exploits an adaptive radius in each iteration that contains first- and second-order information. The properties of global convergence and local superlinearity of the new algorithm are established under standard conditions. Numerical experiments on a set of test functions show the effectiveness of the proposed algorithm.
In this study, we present a spectral conjugate gradient method with a built-in restart feature tailored for unconstrained optimization problems. We introduce a selection of bounded spectral parameters, develop an inno...
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In this study, we present a spectral conjugate gradient method with a built-in restart feature tailored for unconstrained optimization problems. We introduce a selection of bounded spectral parameters, develop an innovative truncation strategy for the RMIL-type conjugate parameter, and establish a novel restart mechanism within our composite search direction. Regardless of the selected bounded spectral parameter and the line search employed, we demonstrate that our proposed search direction meets the sufficient descent property. Furthermore, we establish its global convergence under standard assumptions, including the use of the weak Wolfe line search to generate step size. Numerical comparisons with existing methods highlight the superior performance of our presented methods in addressing unconstrained optimization. Ultimately, we apply the method to solve image restoration problems.
Conjugate gradient (CG) methods are a popular class of iterative methods for solving linear systems of equations and nonlinear optimization problems. Motivated by the construction of some modern CG methods, we propose...
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Conjugate gradient (CG) methods are a popular class of iterative methods for solving linear systems of equations and nonlinear optimization problems. Motivated by the construction of some modern CG methods, we propose two modified CG methods, named DHS* and DPRP*. Under the strong Wolfe line search (SWLS), the two presented methods are proven to be sufficient descent and globally convergent. Preliminary numerical results show that the DHS* and DPRP* methods are effective for the given test problems.
We present a new diagonal quasi-Newton method for solving unconstrained optimization problems based on the weak secant equation. To control the diagonal elements, the new method uses new criteria to generate the Hessi...
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We present a new diagonal quasi-Newton method for solving unconstrained optimization problems based on the weak secant equation. To control the diagonal elements, the new method uses new criteria to generate the Hessian approximation. We establish the global convergence of the proposed method with the Armijo line search. Numerical results on a collection of standard test problems demonstrate the superiority of the proposed method over several existing diagonal methods.
We know many conjugate gradient algorithms (CG) for solving unconstrained optimization problems. In this paper, based on the three famous Liu-Storey (LS), Fletcher-Reeves (FR) and Polak-Ribiere-Polyak (PRP) conjugate ...
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We know many conjugate gradient algorithms (CG) for solving unconstrained optimization problems. In this paper, based on the three famous Liu-Storey (LS), Fletcher-Reeves (FR) and Polak-Ribiere-Polyak (PRP) conjugate gradient methods, a new hybrid CG method is proposed. Furthermore, the search direction satisfies the sufficient descent condition independent of the line search. Likewise, we prove, under the strong Wolfe line search, the global convergence of the new method. In this respect, numerical experiments are performed and reported, which show that the proposed method is efficient and promising. In virtue of this, the application of the proposed method for solving regression models of COVID-19 is provided.
In this paper, we studied a two member family of diagonal conjugate gradient like methods for unconstrained minimization problems. The proposed search directions of the methods are obtained by incorporating a diagonal...
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In this paper, we studied a two member family of diagonal conjugate gradient like methods for unconstrained minimization problems. The proposed search directions of the methods are obtained by incorporating a diagonal Hessian approximation approach with the modifications of the Polak-Ribiere-Polyak and Liu-Storey parameters. The resulting directions guarantees the sufficient decrease of the objective function free from any line search. The global convergence of the proposed methods using both the Wolfe and Armijotype line search conditions without the convexity assumption on the function is provided. Furthermore, the R-linear convergence rate of the methods are analyzed under Wolfe line search condition. Numerical experiments demonstrated the performance of the method on general unconstrained minimization problems and image restoration problem.
In this paper, a three-dimensional subspace conjugate gradient method is proposed, in which the search direction is generated by minimizing the approximation model of the objective function in a three-dimensional subs...
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In this paper, a three-dimensional subspace conjugate gradient method is proposed, in which the search direction is generated by minimizing the approximation model of the objective function in a three-dimensional subspace. The approximation model is not unique and is alternative between quadratic model and conic model by the specific criterions. The strategy of initial stepsize and nonmonotone line search are adopted, and the global convergence of the presented algorithm is established under mild assumptions. In numerical experiments, we use a collection of 80 unconstrained optimization test problems to show the competitive performance of the presented method.
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