Model-based optimization (MBO) is a smart approach to tuning the hyperparameters of machine learning algorithms with less CPU time and manual effort than standard grid search approaches. The core idea behind MBO is to directly evaluate fewer points within a hyperparameter space, and to instead use a “surrogate model” which estimates what the result of your objective function would be in new locations by interpolating (not linearly) between the observed results in a small sample of initial evaluations. Many methods can be used to construct the surrogate model. This post will focus on implementing the bayesian method of Gaussian Process (GP) smoothing (aka “kriging”) which is borrowed from – and particularly well-suited to – spatial applications.
