AutoFolio: Algorithm Configuration for Algorithm Selection

Marius Lindauer, Holger H. Hoos, Frank Hutter, Torsten Schaub

Abstract: Algorithm selection (AS) techniques — which involve choosing from a set of algorithms the one expected to solve a given problem instance most efficiently — have substantially improved the state-of-the-art in solving many prominent AI problems, such as SAT, CSP, ASP, MAXSAT, and QBF.Although several AS procedures have been introduced,not too surprisingly, none of them dominates all others across all AS scenarios.Furthermore, these procedures have parameters whose optimal values vary across AS scenarios.This holds specifically for the machine learning techniques that form the core of current AS proceduresand for their hyperparameters. Therefore, to successfully apply AS to new problems, algorithms and benchmark sets, two questions need to be answered:(i) how to select an AS approach and (ii) how to set its parameters effectively.We address both of these problems simultaneously by using automated algorithm configuration.Specifically, we demonstrate that we can use algorithm configurators to automatically configure clasp folio 2,which implements a large variety of different AS approaches and their respective parameters in a single highly parameterized algorithm framework.We demonstrate that this approach, dubbed auto folio, can significantly improve the performance of clasp folio 2 on 11 out of the 12 scenarios from the Algorithm Selection Library and leads to new state-of-the-art algorithm selectors for 8 of these scenarios.