We study the vehicle routing problem with simultaneous pickup and delivery and handling costs. A fleet of vehicles operates from a single depot to service all customers, which need a a delivery or a pickup, but usually both. All delivery items originate from the depot, and all pickup items go to the depot. The items on the vehicles are organized as linear stacks where only the last loaded item of each stack is accessible (LIFO). Handling operations are required if the delivery items are not the last loaded ones.
We take exactly the situation as described in Hornstra et al. (2020). With one exception: there are multiple linear stacks. The last item of each stack is directly accessible from the rear of the truck, regardless of the length of this stack and regardless the length of the other stacks. The truck capacity is Q, and there are σ stacks, hence maximum length of a stack is Q/σ. When loading items, it can be decided which stack(s) to put the item(s) in. Also when reconfiguring, a choice of stack must be made.
A full report on our solution to this problem is made available in
heuristic/report.pdf.
For the heuristic, see heuristic/README.md. For the validator, see
validator/README.md. Both assume the packages listed in the Pipfile are
available.
- Hornstra, Richard P., Allyson Silva, Kees Jan Roodbergen, and Leandro C. Coelho. 2020. "The vehicle routing problem with simultaneous pickup and delivery and handling costs". Computers and Operations Research. 115.