An algorithm for minimizing the largest eigenvalue of an affine combination of symmetric matrices is presented. The nonsmooth problem is transformed into an equivalent smooth constrained problem, which is solved by a ...
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An algorithm for minimizing the largest eigenvalue of an affine combination of symmetric matrices is presented. The nonsmooth problem is transformed into an equivalent smooth constrained problem, which is solved by a predictor-corrector interior-point method taking full advantage of the differentiability and convexity. Some promising numerical results obtained from a preliminary implementation are included.
Mathematical models are considered as input-output systems. The input is data (technological coefficients, available energy, prices) and the output is the feasible set, the set of optimal solutions, and the optimal va...
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Mathematical models are considered as input-output systems. The input is data (technological coefficients, available energy, prices) and the output is the feasible set, the set of optimal solutions, and the optimal value. We study when output is a continuous function of input and identify optimal (minimal) realizations of mathematical models. These are states of the model having the property that every stable perturbation of input results in a locally worse (higher) value of the optimal value function. In input optimization we “optimize” mathematical model rather than a specific mathematical program.
We consider the problem of minimizing the sum of a convex-concave function and a convex function over a convex set (SFC). It can be reformulated as a univariate minimization problem, where the objective function is ev...
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We consider the problem of minimizing the sum of a convex-concave function and a convex function over a convex set (SFC). It can be reformulated as a univariate minimization problem, where the objective function is evaluated by solving convex optimization. The optimal Lagrangian multipliers of the convex subproblems are used to construct sawtooth curve lower bounds, which play a key role in developing the branch-and-bound algorithm for globally solving (SFC). In this paper, we improve the existing sawtooth-curve bounds to new wave-curve bounds, which are used to develop a more efficient branch-and-bound algorithm. Moreover, we can show that the new algorithm finds an epsilon\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\epsilon $$\end{document}-approximate optimal solution in at most O mml:mfenced close=")" open="("1 epsilon\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$O\left( \frac{1}{\epsilon }\right) $$\end{document} iterations. Numerical results demonstrate the efficiency of our algorithm.
Motivated by the convergence result of mirror-descent algorithms to market equilibria in linear Fisher markets, it is natural for one to consider designing dynamics (specifically, iterative algorithms) for agents to a...
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Motivated by the convergence result of mirror-descent algorithms to market equilibria in linear Fisher markets, it is natural for one to consider designing dynamics (specifically, iterative algorithms) for agents to arrive at linear Arrow-Debreu market equilibria. Jain (SIAM J. Comput. 37(1), 303-318,2007) reduced equilibrium computation in linear Arrow-Debreu markets to the equilibrium computation in bijective markets, where everyone is a seller of only one good and a buyer for a bundle of goods. In this paper, we design an algorithm for computing linear bijective market equilibrium, based on solving the rational convex program formulated by Devanur et al. The algorithm repeatedly alternates between a step of gradient-descent-like updates and a distributed step of optimization exploiting the property of such convex program. Convergence can be ensured by a new analysis different from the analysis for linear Fisher market equilibria.
In this paper we discuss recovering two signals from their convolution in 3 dimensions. One of the signals is assumed to lie in a known subspace and the other one is assumed to be sparse. Various applications such as ...
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In this paper we discuss recovering two signals from their convolution in 3 dimensions. One of the signals is assumed to lie in a known subspace and the other one is assumed to be sparse. Various applications such as super resolution, radar imaging, and direction of arrival estimation can be described in this framework. We introduce a method to estimate parameters of a signal in a low-dimensional subspace which is convolved with another signal comprised of some impulses in time domain. We transform the problem to a convex optimization in the form of a positive semi-definite program using lifting and the atomic norm. We demonstrate that unknown parameters can be recovered by lowpass observations. Numerical simulations show excellent performance of the proposed method.
This paper proposes and analyzes an inexact variant of the proximal generalized alternating direction method of multipliers (ADMM) for solving separable linearly constrained convex optimization problems. In this varia...
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This paper proposes and analyzes an inexact variant of the proximal generalized alternating direction method of multipliers (ADMM) for solving separable linearly constrained convex optimization problems. In this variant, the first subproblem is approximately solved using a relative error condition whereas the second one is assumed to be easy to solve. In many ADMM applications, one of the subproblems has a closed-form solution;for instance, l1 regularized convex composite optimization problems. The proposed method possesses iteration-complexity bounds similar to its exact version. More specifically, it is shown that, for a given tolerance rho>0, an approximate solution of the Lagrangian system associated to the problem under consideration is obtained in at most O(1/rho 2) (resp. O(1/rho) in the ergodic case) iterations. Numerical experiments are presented to illustrate the performance of the proposed scheme.
In this paper, we investigate the impact of the locations of the gateways on the performance of the internet. We consider the problem of determining i) the routing assignments for the intranet and internet traffic and...
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In this paper, we investigate the impact of the locations of the gateways on the performance of the internet. We consider the problem of determining i) the routing assignments for the intranet and internet traffic and ii) the number of gateways and their locations to interconnect existing data networks to minimize a linear combination of the average internet and intranet packet delays subject to a cost constraint on the amount to be spent to establish the gateways. This joint routing and topological design problem is important in the design of internets and should be solved before networks are actually interconnected. This problem is formulated as a nonlinear combinatorial optimization problem. When the gateway locations are fixed, the resulting routing problem is not a convex programming problem. This is unexpected since the routing problem in datagram networks is usually formulated as a convex program, We develop an algorithm based upon Lagrangian relaxation to solve this problem. In the computational experiments, the algorithm was shown to be effective in interconnecting i) two WAN's and ii) two grid networks. The experiments also showed that the algorithm finds better feasible solutions than an exchange heuristic.
This paper analyzes the iteration-complexity of a generalized alternating direction method of multipliers (G-ADMM) for solving separable linearly constrained convex optimization problems. This ADMM variant, first prop...
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This paper analyzes the iteration-complexity of a generalized alternating direction method of multipliers (G-ADMM) for solving separable linearly constrained convex optimization problems. This ADMM variant, first proposed by Bertsekas and Eckstein, introduces a relaxation parameter into the second ADMM subproblem in order to improve its computational performance. It is shown that, for a given tolerance epsilon>0, the G-ADMM with (0,2) provides, in at most O(1/epsilon 2) iterations, an approximate solution of the Lagrangian system associated to the optimization problem under consideration. It is further demonstrated that, in at most O(1/epsilon) iterations, an approximate solution of the Lagrangian system can be obtained by means of an ergodic sequence associated to a sequence generated by the G-ADMM with (0,2]. Our approach consists of interpreting the G-ADMM as an instance of a hybrid proximal extragradient framework with some special properties. Some preliminary numerical experiments are reported in order to confirm that the use of >1 can lead to a better numerical performance than =1 (which corresponds to the standard ADMM).
Binary non-linear programs belong to the class of combinatorial problems which are computationally hard even to approximate. This paper aims to explore some conditions on the problem structure, under which the resulti...
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Binary non-linear programs belong to the class of combinatorial problems which are computationally hard even to approximate. This paper aims to explore some conditions on the problem structure, under which the resulting problem can be well approximated. Particularly, we consider a setting when both objective function and constraint are low-rank functions, which depend only on a few linear combinations of the input variables, and provide polynomial time approximation schemes. Our result generalizes and unifies some existing results in the literature. (C) 2021 Elsevier B.V. All rights reserved.
We investigate recovery of nonnegative vectors from non-adaptive compressive measurements in the presence of noise of unknown power. In the absence of noise, existing results in the literature identify properties of t...
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We investigate recovery of nonnegative vectors from non-adaptive compressive measurements in the presence of noise of unknown power. In the absence of noise, existing results in the literature identify properties of the measurement that assure uniqueness in the non-negative orthant. By linking such uniqueness results to nullspace properties, we deduce uniform and robust compressed sensing guarantees for nonnegative least squares. No l(1)-regularization is required. As an important proof of principle, we establish that m x n random i.i.d. 0/1-valued Bernoulli matrices obey the required conditions with overwhelming probability provided that m = O(s log(n/s)). We achieve this by establishing the robust nullspace property for random 0/1-matrices-a novel result in its own right. Our analysis is motivated by applications in wireless network activity detection.
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