Vehicle routing with time window Implementation in Python

Question

I am working on a use case, in which I have multiple vehicles as depot,delivery boys and set of customers from diverse location to serve fresh food. Customers would place an order from an application,then delivery boy receives the order and get the food from Van and then deliver it with some promised delivery time(15 mins). I want to optimize this problem so that operational cost for traveling is reduced and delivery time is minimized. Just wanted to know is there any implementation in Python so solve VRPTW problem ? Please help

Answer 1

You can find implementation of Dijkstra shortest path algorithm in python.

An example implementation is

http://code.activestate.com/recipes/577506-dijkstra-shortest-path-algorithm/

Answer 2

read some research papers on vehicle routing problem. i've seen some of the papers provides a complete algorithm on vehicle routing, and they come in different ways by considering multiple criteria. hence, it's possible to implement one or more of the algorithms provided in these papers and do a test to use the optimal solution.

Answer 3

If you want to solve a routing problem, the very first thing to figure out is what variant of the vehicle routing problem you're solving. I'm going to assume the vans are stationary (i.e. you're not trying to optimise the positioning of the vans themselves as well). Firstly the problem is dynamic as it's happening in realtime - i.e. it's a realtime route optimisation problem. If the delivery people are pre-assigned to a single van, then this might be considered a dynamic multi-trip vehicle routing problem (with time windows obviously). Generally speaking though it's a dynamic pickup and delivery vehicle routing problem, as presumably the delivery people can pickup from different vans (so DPDVRPTW). You'd almost certainly need soft timewindows as well, making it a DPDVRP with soft time windows. Soft time windows are essential because in a realtime setting you generally want to deliver as fast as possible, and so want to minimise how late you are. Normal 'hard' time windows like in the VRPTW don't let you deliver after a certain time, but place no cost penalty on delivering before this time (i.e. they're binary). Therefore you can't use them to minimise lateness.

I'm afraid I don't know of any open source solver in python or any other language that solves the dynamic pickup and delivery vehicle routing problem with soft time windows.

This survey article has a good overview of the subject. We also published a white paper on developing realtime route optimisers, which is probably an easier read than the academic paper. (Disclaimer - I am the author of this white paper).