2.1.1 First GRASP Algorithm
The first GRASP algorithm provides an initial solution for the capacitated vehicle routing problem, taking split delivery as second restriction. Within the construction phase a second GRASP algorithm is applied that solves the 3D bin packing problem which helps us to optimize packing in the vehicle, considering vehicle load weight and the order of delivery of the consignees.
This algorithm receives two entry parameters: a graph (conformed by the starting node and the consignee nodes) and the delivery vehicle list; the algorithm returns the delivery route to be followed by each vehicle.
For the construction of the first GRASP algorithm we use an objective function that has three entry parameters: the traveled distance of the edge, the traffic constant (a value between 1 and 5) and the cost function of the second GRASP algorithm . The objective function to be minimized is shown in equation 3.