Solving Large Scale Uncapacitated Facility Location Problems

We investigate the solution of instances of the uncapacitated facility location problem with at most 3000 potential facility locations and similar number of customers. We use heuristics that produce a feasible integer solution and a lower bound on the optimum. In particular, we present a new heuristic whose gap from optimality was generally below 1%. The heuristic combines the volume algorithm and a recent approximation algorithm based on randomized rounding. Our computational experiments show that our heuristic compares favorably against DUALOC.