Improving Novelty Search with a Surrogate Model and Accuracy Objectives to Build High-Performing Ensembles of Classifiers
摘要
Neuroevolution combined with Novelty Search to promote behavioural diversity is capable of constructing high-performing ensembles for classification. However, using gradient descent to train evolved architectures during the search can be computationally prohibitive. We have proposed a method to overcome this limitation by using a surrogate model which estimates the behavioural distance between two neural network architectures, required to calculate novelty scores. This has demonstrated a speedup of 10 times over previous work, significantly improving on previous reported results on three benchmark datasets from Computer Vision—CIFAR-10, CIFAR-100, and SVHN. This method makes an explicit search for diversity considerably more tractable for the same bounded resources. Here we investigate a range of search methods that span the full spectrum of favouring accuracy, diversity, or different combinations of both. Surprisingly, we show that multiple unique combinations between a diversity metric and accuracy give rise to similar results. This enables us to posit the existence of a diversity-accuracy duality in ensembles of classifiers, which suggests that there might not be a need to find a trade-off between the two.