Table of Contents
Fetching ...

Global Optimisation of Black-Box Functions with Generative Models in the Wasserstein Space

Tigran Ramazyan, Mikhail Hushchyn, Denis Derkach

TL;DR

A new uncertainty estimator for gradient-free optimisation of black-box simulators using deep generative surrogate models that is more robust to the shape of both the black box function and the stochastic response of the black box than state-of-the-art methods.

Abstract

We propose a new uncertainty estimator for gradient-free optimisation of black-box simulators using deep generative surrogate models. Optimisation of these simulators is especially challenging for stochastic simulators and higher dimensions. To address these issues, we utilise a deep generative surrogate approach to model the black box response for the entire parameter space. We then leverage this knowledge to estimate the proposed uncertainty based on the Wasserstein distance - the Wasserstein uncertainty. This approach is employed in a posterior agnostic gradient-free optimisation algorithm that minimises regret over the entire parameter space. A series of tests were conducted to demonstrate that our method is more robust to the shape of both the black box function and the stochastic response of the black box than state-of-the-art methods, such as efficient global optimisation with a deep Gaussian process surrogate.

Global Optimisation of Black-Box Functions with Generative Models in the Wasserstein Space

TL;DR

A new uncertainty estimator for gradient-free optimisation of black-box simulators using deep generative surrogate models that is more robust to the shape of both the black box function and the stochastic response of the black box than state-of-the-art methods.

Abstract

We propose a new uncertainty estimator for gradient-free optimisation of black-box simulators using deep generative surrogate models. Optimisation of these simulators is especially challenging for stochastic simulators and higher dimensions. To address these issues, we utilise a deep generative surrogate approach to model the black box response for the entire parameter space. We then leverage this knowledge to estimate the proposed uncertainty based on the Wasserstein distance - the Wasserstein uncertainty. This approach is employed in a posterior agnostic gradient-free optimisation algorithm that minimises regret over the entire parameter space. A series of tests were conducted to demonstrate that our method is more robust to the shape of both the black box function and the stochastic response of the black box than state-of-the-art methods, such as efficient global optimisation with a deep Gaussian process surrogate.
Paper Structure (13 sections, 2 theorems, 22 equations, 9 figures, 5 tables, 1 algorithm)

This paper contains 13 sections, 2 theorems, 22 equations, 9 figures, 5 tables, 1 algorithm.

Key Result

Lemma 1

(Existence of a minimum at the boundary, lanzetti2022firstorder) There exists a worst-case probability measure $\mu^*$ attaining the supremum (eq:unc_1) such that $\mathbb{W}(\nu, \mu^*) = \varepsilon$.

Figures (9)

  • Figure 1: Experiment results - comparison of EGO and WU-GO. See Section 4.1 for more details.
  • Figure 2: SHiP Muon Shield optimisation results.
  • Figure 3: Ablation study for optimal values of $\kappa$.
  • Figure 4: Experiment results - comparison of LCB and WU-GO.
  • Figure 5: Starting SHiP muon shield configuration.
  • ...and 4 more figures

Theorems & Definitions (5)

  • Definition 1
  • Definition 2
  • Lemma 1
  • Lemma 2
  • proof