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Multi-Trip VRPTW


#1

Hi Jspriters,

I am trying to model the multi-trip, multi-vehicle VRPTW using jsprit. I am aware that the tutorial: https://www.graphhopper.com/blog/2016/07/21/how-to-model-multiple-delivery-routes-with-a-single-vehicle/ provides an idea. It seems defining services as shipments might make the algorithm run slower. Is there anyway to model the problem differently (using jsprit)? My problem has hundreds of customers and 10-20 vehicles and hence I am afraid defining these many shipments might not be the best way. Please enlighten me. Thank you for your time.


#2

I had a similar problem, but didn’t notice significant drop in calculation time.
In 2 to 5 minutes i got good results.
If all vehicles are the same, you can avoid involving them in the algorithm by setting

FleetSize.INFINITE


#3

Thanks traveler a lot for your response. I thought defining each service as a shipment is a bit overkill and I was thinking about defining for each vehicle (e.g. veh1) a number of vehicle_routes (e.g. veh1a, veh1b, veh1c…) which are essentially the same vehicle except that there are hard constraints requiring:

veh1a.end <= veh1b.start etc.

but I don’t know where/how to start. I would appreciate if anyone has any suggestion. Thank you.


#4

Hi everyone,

I have the same problem as deliveryboy. When I defined shipments the algorithm runs much slower. I was wondering if you have been successful to fix this problem.