Читать книгу Optimization and Machine Learning - Patrick Siarry - Страница 17

In the literature, several variants of the 2L-VRP have been defined, such as the 2L-CVRP with time constraints, the 2L-CVRP with backhaul constraints and the 2L-CVRP with pickup and delivery constraints. Some constraints are related to the loading configuration: (1) oriented loading, where items cannot be rotated; (2) sequential loading, where items should be loaded in reverse according to customer visits; (3) unrestricted loading, allowing items to be reloaded during the routing process; and (4) non-oriented or rotated loading, allowing items to be rotated 90° inside the vehicle. Four versions of the 2L-CVRP (2|SO|L, 2|SR|L, 2|UO|L and 2|UR|L) are designed.