We present a new branch-and-cut algorithm for the well-known capacitated vehicle routing problem (CVRP). The algorithm uses a variety of cutting planes, including capacity, framed capacity, strengthened comb, multistar, partial multistar, extended hypotour inequalities, and classical Gomory mixed-integer cuts. For each of these classes of inequalities we describe our separation algorithms in detail. Also we describe the other important ingredients of our branch-and-cut algorithm, such as the branching rules, the node selection strategy, and the cut pool management. Computational results, for a large number of instances, show that the new algorithm is competitive. In particular, we solve three instances of Augerat to optimality for the first time.
This was eventually published as: J. Lysgaard, A.N. Letchford & R.W. Eglese (2004) A new branch-and-cut algorithm for the capacitated vehicle routing problem. Math. Program., 100(2), 423-445.