questions about how to model CVRP constraints

[moonlioght]

Hello,

Fisrt of all , I really admire your work and repository. I am very curious about how to model the condition that a vehicle meets the needs of all customers by repeatedly shipping goods into a MIP constraint? I'm having some difficulty with this. If it is convenient, can you provide the Gurobi code. Maybe I can find the answer from it.

[wouterkool]

Hi! Thanks for your compliments. I'm not sure what you mean exactly, if you refer to split delivery VRP, I don't have a solution for modelling that as a MIP which is the reason why in the paper we don't have Gurobi as a baseline for SDVRP.

[moonlioght]

Thanks for the quick reply, I was referring to Capacitated VRP.
Because in Capacitated VRP, a vehicle with capacity D is set to serve all the customer nodes. So what if we ensure that all customer nodes can be served? What I understand is that when serving each route, the vehicle is in a full state (that is, the capacity is D).
That is what I mentioned above by repeatedly filling the vehicle to meet the needs of all customers.


My confusion is how to convert this setting into MIP constraints and implement it with Gurobi？

[wouterkool]

Hi,

I do not have an implementation for Gurobi as the number is reported from https://arxiv.org/pdf/1802.04240.pdf, see 'Optimal' in table 2 in appendix C.2. However, you can find some implementations here: https://github.com/ruthmair/vrp/blob/main/cvrp.ipynb. I didn't test them but they are made by Gurobi staff so I think they are good.

[moonlioght]

Thanks very much!