An Evaluation Function for Lines of Action

Lines of Action (LOA) is a two-person zero-sum chess-like connection game. Building an evaluation function for LOA is a difficult task because not much knowledge about the game is available. In this paper the evaluation function of the tournament program MIA is explained. This evaluator consists of the following nine features: concentration, centralisation, centre-of-mass position, quads, mobility, walls, connectedness, uniformity, and player to move. These features have resulted in the evaluator MIA IV. The evaluator is tested in a tournament against other LOA evaluators, which have performed well at the previous Computer Olympiads. Experiments show that MIA IV defeats them with large margins. It turns out that the evaluator even performs better at deeper searches.