车辆路线问题 - 如何完成/确定何时访问某些位置？

Question

I have VRP problem. I have vehicles starting positions and I have distance matrix. I want solution to be terminated/finished when certain locations are visited.

So I don't want it to actually visit each index of location_matrix but if visiting different index beside "MUST VISITS" make for better solution then I have no problem. Because you know sometimes going from directly 1 to 3 is slower than 1-2-3. (visiting 2 which is not necessary but make it for shortcut)

I defined a dummy depot which cost 0, I used this for end because if you use starts you have to define ends. And I put ends 000 which are basically ending position. You might ask why you didnt put your "JOB" locations. But this means they have to end there. So it doesn't seem optimal because example one vehicle could be really near to both of "JOB" locations but if it terminates / ends because it has END defined vehicle would stop.

I have no idea how to make this work. Basically what I want that if certain locations are visited once just terminate - that's the solution. So if jobs are (1,3,5) and Vehicle 1 visited 1,3 and Vehicle 2 just visited 2 it should be finished.

If I use solver in ortools It will be like TSP problem which will try to visit each location in distance_matrix. I don't exactly want this. It could visit if results better solution(does it make sense?) but it should be focusing on "JOB" locations and how to go them faster

Answer 1

Potential approach: Compute a new distance matrix with only the "MUST VISIT" locations, and run a VRP with this matrix.

• Compute a distance matrix with only the "MUST VISIT" locations.
• Each cell contains the shortest path between two "MUST VISIT" locations.
• Store all the pairwise shortest paths found.
• Run a regular VRP on this distance matrix.
• Reconstruct the full path using the shortest paths found earlier.