Given a directed graph G(V,A), the p-Median problem consists of determining p nodes (the median nodes) minimizing the total distance from the other nodes of the graph. We present a Branch-and-Cut algorithm yielding provably good solutions for instances up to 3795 nodes (14,402,025 variables). Key ingredients of our approach are: lagrangian relaxation, a simple procedure to choose

## Citation

Math. Program., Ser. A (2006) Digital Object Identifier (DOI) 10.1007/s10107-005-0700-6