Delivery and pickup problem

Awaiting user input

Jantine Paasschens

• June 11, 2021 21:02

Hi, I am working on a pick up and delivery problem using Gurobi solver. As we have added all the constraints, the program should work but the problem is that each vehicle should travel one route starting and ending at the depot. The vehicle does this but there are several pickup/delivery points that are not included in the route. There are multiple routes that do not start or end at the depot and they are not included in the route per vehicle. We are not sure how to fix the problem, if needed I can send a screenshot of the output and the code.

Thank you in advance!

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• Official comment

  

  Simranjit Kaur

  Gurobi Staff

  • December 06, 2024 00:30

  This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum. Or why not try our AI Gurobot?.
• 

  Alison Cozad

  Gurobi Staff

  • July 02, 2021 19:59

  Perhaps you could try fixing the missing delivery/pickup points in the route and forcing the routes to start/end at the depot.  Then solve to see if the model remains feasible. 

  If the model turns out to be infeasible, you can use the tools described in the following links to see which constraint may be causing the issue: Diagnose and cope with infeasibility and How do I determine why my model is infeasible?

  If the model is still feasible, we can dig a bit deeper.  It would help if you can provide the math model, code, and some more detail on which variables are giving the unexpected results.

   

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