Minimal forward checking

Abstract

Forward Checking (FC) is a highly regarded complete search algorithm used to solve constraint satisfaction problems. In this paper a lazy variant of FC called minimal forward checking (MFC) is introduced. MFC is a natural marriage of incremental FC and backchecking. Given a variable selection heuristic which does not depend on domain size MPC's worst case performance on any CSP instance is the number of constraint checks performed by FC. Experiments using hard random problems are presented which show that MFC outperforms FC especially for problems with large domain sizes and/or a large number of variables.<>