Liyuan Cao

First- and Second-Order High Probability Complexity Bounds for Trust-Region Methods with Noisy Oracles

  • Liyuan Cao
  • Albert S. Berahas
  • Katya Scheinberg
    • Categories Nonlinear Optimization, Unconstrained Optimization Tags , , ,

    In this paper, we present convergence guarantees for a modified trust-region method designed for minimizing objective functions whose value is computed with noise and for which gradient and Hessian estimates are inexact and possibly random. In order to account for the noise, the method utilizes a relaxed step acceptance criterion and a cautious trust-region radius … Read more

    A Theoretical and Empirical Comparison of Gradient Approximations in Derivative-Free Optimization

  • Albert S. Berahas
  • Liyuan Cao
  • Katya Scheinberg
  • Krzysztof Choromanski
    • Categories Nonlinear Optimization, Unconstrained Optimization Tags , , , ,

    In this paper, we analyze several methods for approximating gradients of noisy functions using only function values. These methods include finite differences, linear interpolation, Gaussian smoothing and smoothing on a unit sphere. The methods differ in the number of functions sampled, the choice of the sample points, and the way in which the gradient approximations … Read more