We study monotone function-constrained variational inequalities (FCVIs) whose feasible region is the intersection of a projection-friendly set and several convex function constraints; both the operator and the constraint functions may be smooth, nonsmooth, and/or stochastic. Computing the projection operator is challenging for FCVIs. We introduce the adaptive operator extrapolation (AdOpEx) method, which employs an operator extrapolation on the Karush–Kuhn–Tucker operator of the FCVI in a smooth deterministic setting. Because this operator is not uniformly Lipschitz continuous in the Lagrange multipliers, we employ an adaptive two-timescale algorithm leading to bounded multipliers and achieving the optimal [Formula: see text] convergence rate. For the nonsmooth and stochastic VIs, we introduce design changes to the AdOpEx method and propose a novel P-OpEx method that takes a partial extrapolation. It converges at the rate of [Formula: see text] when both the operator and constraints are stochastic or nonsmooth. This method has suboptimal dependence on the noise and Lipschitz constants of function constraints. We propose a constraint extrapolation approach leading to the OpConEx method that improves this dependence by an order of magnitude. All our algorithms also extend to solving saddle point problems with jointly convex function constraints that couple the primal and dual variables. Within this structured class of problems, our methods preserve their respective complexity guarantees, establishing what we believe to be the first such comprehensive complexity results. Funding: D. Boob and M. Khalafi were partially supported by the National Science Foundation [Grants 2245705 and 2340858]. D. Boob was partially supported by the Office of Naval Research [Grant N000142412749]. Q. Deng was partially supported by the National Natural Science Foundation of China [Grants 12571325 and 72394364/72394360] and the Natural Science Foundation of Shanghai [Grant 24ZR1421300].
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A Primal-Dual Approach to Constrained Markov Decision Processes with Applications to Queue Scheduling and Inventory Management
In many operations management problems, we need to make decisions sequentially to minimize the cost, satisfying certain constraints. One modeling approach to such problems is the constrained Markov decision process (CMDP). In this work, we develop a data-driven primal-dual algorithm to solve CMDPs. Our approach alternatively applies regularized policy iteration to improve the policy and subgradient ascent to maintain the constraints. Under mild regularity conditions, we show that the algorithm converges at rate [Formula: see text], where T is the number of iterations, for both the discounted and long-run average cost formulations. Our algorithm can be easily combined with advanced deep learning techniques to deal with complex large-scale problems with the additional benefit of straightforward convergence analysis. When the CMDP has a weakly coupled structure, our approach can further reduce the computational complexity through an embedded decomposition. We apply the algorithm to two operations management problems: multiclass queue scheduling and multiproduct inventory management. Numerical experiments demonstrate that our algorithm, when combined with appropriate value function approximations, generates policies that achieve superior performance compared with state-of-the-art heuristics. This paper was accepted by Baris Ata, stochastic models and simulation. Funding: Y. Chen was supported by the Hong Kong Research Grants Council, Early Career Scheme Fund [Grant 26508924], and partially supported by a grant from the National Natural Science Foundation of China [Grant 72495125]. J. Dong was supported by the National Science Foundation [Grant 1944209]. Supplemental Material: The data files are available at https://doi.org/10.1287/mnsc.2022.03736 .
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- Award ID(s):
- 1944209
- PAR ID:
- 10591738
- Publisher / Repository:
- INFORMS
- Date Published:
- Journal Name:
- Management Science
- ISSN:
- 0025-1909
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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