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Coordinate descent methods have considerable impact in global optimization because global (or, at least, almost global) minimization is affordable for low-dimensional problems. Coordinate descent methods with high-order regularized models for smooth nonconvex box-constrained minimization are introduced in this work. High-order stationarity asymptotic convergence and first-order stationarity worst-case evaluation complexity bounds are established. The computer work that is necessary for obtaining first-order ε -stationarity with respect to the variables of each coordinate-descent block is O (ε - (p + 1) / p) whereas the computer work for getting first-order ε -stationarity with respect to all the variables simultaneously is O (ε - (p + 1)) . Numerical examples involving multidimensional scaling problems are presented. The numerical performance of the methods is enhanced by means of coordinate-descent strategies for choosing initial points. [ABSTRACT FROM AUTHOR]

At each iteration of a block coordinate descent method one minimizes an approximation of the objective function with respect to a generally small set of variables subject to constraints in which these variables are involved. The unconstrained case and the case in which the constraints are simple were analyzed in the recent literature. In this paper we address the problem in which block constraints are not simple and, moreover, the case in which they are not defined by global sets of equations and inequations. A general algorithm that minimizes quadratic models with quadratic regularization over blocks of variables is defined and convergence and complexity are proved. In particular, given tolerances δ > 0 and ε > 0 for feasibility/complementarity and optimality, respectively, it is shown that a measure of (δ , 0) -criticality tends to zero; and the number of iterations and functional evaluations required to achieve (δ , ε) -criticality is O (ε - 2) . Numerical experiments in which the proposed method is used to solve a continuous version of the traveling salesman problem are presented. [ABSTRACT FROM AUTHOR]