Recently, there is an emerging trend to apply deep reinforcement learning solve the vehicle routing problem (VRP), where a learnt policy governs selection of next node for visiting. However, existing methods could not handle well pairing and precedence relationships in pickup delivery (PDP), which representative variant VRP. To address this challenging issue, we leverage novel neural network in...

In this work, the Multi-Depot Green VRP with Pickups and Deliveries (MDGVRP-PD) is studied. It a routing optimization problem in which objective to construct set of vehicle routes considering multiple depots one-to-one pickup delivery operations that minimize emissions through fuel consumption, depends on weight travel distance. problems, goods must be transported between single origin its asso...

The One-Commodity Pickup-and-Delivery Travelling Salesman Problem (1-PDTSP) is defined on a directed graph as follows. A node of the graph represents a depot and the other nodes represent customers. Every customer has a positive or negative demand of a product. The product is the same for all customers. Customers with positive demand are called pickups and customers with negative demand are cal...

Abstract: In order to solve the vehicle routing problem with pickup and delivery (VRPPD), this paper proposed an improved quantum genetic algorithm based on different constraint conditions. Firstly, a mathematical model was established aiming at minimizing the dispatching time and the total cost. Secondly, the paper proposes the improved quantum genetic algorithm and non dominated sorting strat...

In this paper, we study a variant of the well-known single-vehicle pickup and delivery problem where the demands can be unloaded/reloaded at any node. By proving new complexity results, we give the minimum information which is necessary to represent feasible solutions. Using this, we present integer linear programs for both the unitary and the general versions. We then show that the associated ...

In this paper, we consider a variant of the pickup and delivery problem where any demand may be dropped off elsewhere than at its destination, picked up later by the same or another vehicle, and so on until it has reached its destination. We discuss the complexity of this problem and present two mixed-integer linear programming formulations based on a space-time graph. We describe some valid in...

The Vehicle Routing Problem with Simultaneous Pickup-Delivery and Time Windows (VRPSPDTW) has attracted much research interest in the last decade, due to its wide application modern logistics. Since VRPSPDTW is NP-hard exact methods are only applicable small-scale instances, heuristics meta-heuristics commonly adopted. In this paper we propose a novel Memetic Algorithm efficienT local search Ex...