3.7.164. n-queens
A constraint that can be used for modelling the -queen problem. Place queens on an by chessboard in such a way that no queen attacks another. Two queens attack each other if they are located on the same column, on the same row or on the same diagonal. A constructive method for arbitrary was first given in [FalkowskiSchmitz86]. An effective heuristics for the -queen problem was given in [Kale90]. It consists of starting to place the queens in the centre of the chessboard so that they eliminate the maximum number of potential positions.