Qiankun Shi

Curvature-oriented variance reduction methods for nonconvex stochastic optimization

  • Qiankun Shi
  • Shiji Zuo
  • liuyx
  • Xiao Wang
    • Categories Constrained Nonlinear Optimization, Nonlinear Optimization Tags , , , ,

    When pursuing an approximate second-order stationary point in nonconvex constrained stochastic optimization, is it possible to design a stochastic second-order method that achieves the same sample complexity order as in the unconstrained setting? To address this question in this paper, we first introduce Carme, a curvature-oriented variance reduction method designed for unconstrained nonconvex stochastic optimization. … Read more

    An Exact Penalty Method for Stochastic Equality-Constrained Optimization

  • Yawen Cui
  • Qiankun Shi
  • Xiao Wang
  • Xiantao Xiao
    • Categories Constrained Nonlinear Optimization, Nonlinear Optimization

    In this paper, we study a penalty method for stochastic equality-constrained optimization, where both the objective and constraints are expressed in general expectation form. We introduce a novel adaptive strategy for updating the penalty parameter, guided by iteration progress to balance reductions in the penalty function with improvements in constraint violation, while each penalty subproblem … Read more

    A momentum-based linearized augmented Lagrangian method for nonconvex constrained stochastic optimization

  • Qiankun Shi
  • Xiao Wang
  • Hao Wang
    • Categories Constrained Nonlinear Optimization, Nonlinear Optimization, Stochastic Programming Tags , , , , ,

    Nonconvex constrained stochastic optimization has emerged in many important application areas. Subject to general functional constraints it minimizes the sum of an expectation function and a nonsmooth regularizer. Main challenges arise due to the stochasticity in the random integrand and the possibly nonconvex functional constraints. To address these issues we propose a momentum-based linearized augmented … Read more