Convergence of Mean-Field Langevin Stochastic Descent-Ascent for Distributional Minimax Optimization

  • Rui Gao
    • Categories Stochastic Programming

    We study convergence properties of the discrete-time Mean-Field Langevin Stochastic Descent-Ascent (MFL-SDA) algorithm for solving distributional minimax optimization. These problems arise in various applications, such as zero-sum games, generative adversarial networks and distributionally robust learning. Despite the significance of MFL-SDA in these contexts, the discrete-time convergence rate remains underexplored. To address this gap, we establish … Read more

    A stochastic gradient method for trilevel optimization

  • Tommaso Giovannelli
  • Griffin D. Kent
  • Luis Nunes Vicente
    • Categories Multi-Criteria Optimization Tags , , ,

    With the success that the field of bilevel optimization has seen in recent years, similar methodologies have started being applied to solving more difficult applications that arise in trilevel optimization. At the helm of these applications are new machine learning formulations that have been proposed in the trilevel context and, as a result, efficient and … Read more

    An inexact alternating projection method with application to matrix completion

  • Stefania Bellavia
  • Simone Rebegoldi
  • Mattia Silei
    • Categories Nonlinear Optimization, Other Topics Tags , , , ,

    We develop and analyze an inexact regularized alternating projection method for nonconvex feasibility problems. Such a method employs inexact projections on one of the two sets, according to a set of well-defined conditions. We prove the global convergence of the algorithm, provided that a certain merit function satisfies the Kurdyka-Lojasiewicz property on its domain. The … Read more

    Steepest descent method using novel adaptive stepsizes for unconstrained nonlinear multiobjective programming

  • Pham Thi Hoai
    • Categories Convex Optimization, Multi-Criteria Optimization, Nonlinear Optimization Tags , , , ,

    We propose new adaptive strategies to compute stepsizes for the steepest descent method to solve unconstrained nonlinear multiobjective optimization problems without employing any linesearch procedure. The resulting algorithms can be applied to a wide class of nonconvex unconstrained multi-criteria optimization problems satisfying a global Lipschitz continuity condition imposed on the gradients of all objectives. In … Read more

    A Symmetric Primal-Dual method with two extrapolation steps for Composite Convex Optimization

  • Feng Ma
    • Categories Convex Optimization Tags , , ,

    Symmetry is a recurring feature in algorithms for monotone operator theory and convex optimization, particularly in problems involving the sum of two operators, as exemplified by the Peaceman–Rachford splitting scheme. However, in more general settings—such as composite optimization problems with three convex functions or structured convex-concave saddle-point formulations—existing algorithms often exhibit inherent asymmetry. In particular, … Read more

    A surplus-maximizing two-sided multi-period non-convex ISO auction market

  • Richard O'Neill
  • Yonghong Chen
    • Categories (Mixed) Integer Linear Programming, Applications - OR and Management Sciences, Other Topics Tags , , ,

    Since the inception of ISOs, Locational Marginal Prices (LMPs) alone were not market clearing or incentive compatible because an auction winner who offered its avoidable costs could lose money at the LMPs. ISOs used make-whole payments to ensure that market participants did not lose money. Make-whole payments were not public, creating transparency issues. Over time, … Read more

    Responsible Machine Learning via Mixed-Integer Optimization

  • Nathan Justin
  • Qingshi Sun
  • Andrés Gómez
  • Phebe Vayanos
    • Categories Applications - OR and Management Sciences, Integer Programming, Optimization in Data Science Tags , , , , , ,

    In the last few decades, Machine Learning (ML) has achieved significant success across domains ranging from healthcare, sustainability, and the social sciences, to criminal justice and finance. But its deployment in increasingly sophisticated, critical, and sensitive areas affecting individuals, the groups they belong to, and society as a whole raises critical concerns around fairness, transparency … Read more

    Alternating Methods for Large-Scale AC Optimal Power Flow with Unit Commitment

  • Matthew Brun
  • Thomas Lee
  • Dirk Lauinger
  • Xin Chen
  • Xu Andy Sun
    • Categories (Mixed) Integer Nonlinear Programming, Energy Tags , , ,

    Security-constrained unit commitment with alternating current optimal power flow (SCUC-ACOPF) is a central problem in power grid operations that optimizes commitment and dispatch of generators under a physically accurate power transmission model while encouraging robustness against component failures.  SCUC-ACOPF requires solving large-scale problems that involve multiple time periods and networks with thousands of buses within … Read more

    Fast Stochastic Second-Order Adagrad for Nonconvex Bound-Constrained Optimization

  • Stefania Bellavia
  • Serge Gratton
  • Benedetta Morini
  • Philippe L. Toint
    • Categories Bound-constrained Optimization, Data Science Algorithms, Nonlinear Optimization Tags , , , , , ,

    ADAGB2, a generalization of the Adagrad algorithm for stochastic optimization is introduced, which is also applicable to bound-constrained problems and capable of using second-order information when available. It is shown that, given  delta in (0,1) and epsilon in (0,1], the ADAGB2 algorithm needs at most O(epsilon^{-2}) iterations to ensure an epsilon-approximate first-order critical point of … Read more

    PDCS: A Primal-Dual Large-Scale Conic Programming Solver with GPU Enhancements

  • Zikai Xiong
    • Categories Cone Programming, Linear, Cone and Semidefinite Programming, Second-Order Cone Programming

    In this paper, we introduce the Primal-Dual Conic Programming Solver (PDCS), a large-scale conic programming solver with GPU enhancements. Problems that PDCS currently supports include linear programs, second-order cone programs, convex quadratic programs, and exponential cone programs. PDCS achieves scalability to large-scale problems by leveraging sparse matrix-vector multiplication as its core computational operation, which is … Read more