The Sweep method of Gillet and Miller [10] is considered to be an efficient construction method for the VRPs
We have adapted a sweep-first-assignment-second based approach to generate an MT-VRPB initial solution. Initially two sets of open-ended routes are constructed by sweeping through LH and BH nodes separately A distance/cost matrix for the assignment problem is created by including the distances between the end nodes of the open-ended routes. A dummy route containing the depot is also added to the matrix where a number of LH and BH routes are not equal. To produce combined LH–BH routes, the optimal matching is then obtained by solving an assignment problem using ILOG CPLEX 12.5 . optimiser coded with within Microsoft Visual Studio Environment