We propose a novel Bayesian approach to solve stochastic optimization problems that involve finding extrema of noisy, nonlinear functions. Previous work has focused on representing possible functions explicitly, which leads to a two-step procedure of first, doing inference over the function space and second, finding the extrema of these functions. Here we skip the representation step and directly model the distribution over extrema. To this end, we devise a non-parametric conjugate prior based on a kernel regressor. The resulting posterior distribution directly captures the uncertainty over the maximum of the unknown function. Given t observations of the function, the posterior can be evaluated efficiently in time O(t2) up to a multiplicative constant. Finally, we show how to apply our model to optimize a noisy, non-convex, high-dimensional objective function.
['Pedro A. Ortega', 'Jordi Grau-Moya', 'Tim Genewein', 'David Balduzzi', 'Daniel A. Braun']
A Nonparametric Conjugate Prior Distribution for the Maximizing Argument of a Noisy Function