Solution of large weighted equicut problems

Given a weighted undirected graph, the equicut problem consists of finding a partition of the vertex set into two subsets of equal cardinality such that the sum of the weights of the edges belonging to the cut defined by the partition is minimized. The problem is NP-hard and has several practical applications. In recent years a number of algorithms based on metaheuristic techniques have been proposed. In this work we first present a survey of the algorithms from the literature, then we propose a new tabu search algorithm and compare it with the other heuristics through extensive computational experiments on several classes of graphs with up to 4000 nodes and 320 000 edges. The results show that our approach easily determines the optimal solution for small graphs and its average performances are greatly superior to those of the other approximating algorithms.