Ziyu He

Adaptive Importance Sampling Based Surrogation Methods for Bayesian Hierarchical Models, via Logarithmic Integral Optimization

  • Ziyu He
  • Junyi Liu
  • Jong-Shi Pang
    • Categories Constrained Nonlinear Optimization, Nonsmooth Optimization, Stochastic Programming Tags , ,

    We explore Maximum a Posteriori inference of Bayesian Hierarchical Models (BHMs) with intractable normalizers, which are increasingly prevalent in contemporary applications and pose computational challenges when combined with nonconvexity and nondifferentiability. To address these, we propose the Adaptive Importance Sampling-based Surrogation method, which efficiently handles nonconvexity and nondifferentiability while improving the sampling approximation of the … Read more

    Comparing Solution Paths of Sparse Quadratic Minimization with a Stieltjes Matrix

  • Ziyu He
  • Shaoning Han
  • Andrés Gómez
  • Ying Cui
  • Jong-Shi Pang
    • Categories Nonsmooth Optimization, Quadratic Programming, Statistics Tags , , ,

    This paper studies several solution paths of sparse quadratic minimization problems as a function of the weighing parameter of the bi-objective of estimation loss versus solution sparsity. Three such paths are considered: the “L0-path” where the discontinuous L0-function provides the exact sparsity count; the “L1-path” where the L1-function provides a convex surrogate of sparsity count; … Read more