And I have not used it, nor am I involved in it. Just you can see the facilities for overrides etc. Whether it’s user-friendly and a complete model, I don’t know.
What starts out as a “if I could just change this one thing and solve my problems” affair soon degenerates into one of the most complicated and confusing problems imaginable. It’s no longer a purely mathematical problem, you’re throwing customer satisfaction, acts of God, management and operational judgement into the mix.
I’m currently running into this exact problem but it doesn’t seem like a proper solution has been described quite yet. Example:
Vehicle A -----------Service C-------------Service B
Vehicle A is “assigned” to Service B in a 1-job initial route due to a decision in a previous optimization. Service C gets added to the problem since that previous optimization and it’s between Vehicle A and Service B. Despite it being less efficient to do so, I’d like for Vehicle A to go to Service B before Service C. It was my understanding that this is how initial routes worked, but it appears that Service C can get added between Vehicle A and Service B.
Is there any way to treat the initial route ordering of Vehicle A -> Service B as “immutable”? I’ve set the THRESHOLD_ALPHA to 0.0 but that did not seem to help.
One approach that I’m considering is adding a HardRouteConstraint that takes the list of services added to initial routes in its constructor and returns NOT_FULFILLED whenever nextAct is one of the services added to the initial routes.
Thanks in advance for any direction that can be offered here! These discussions have been incredibly helpful.
Hi @adamlafave,
You are right that the “new” jobs (the jobs not in the initial routes) can be inserted before, between, or after the “old” jobs.
You are also right that the approach you described would work to disallow any “new” jobs to be inserted before an “old” job, only that it would be a HardActivityConstraint.
Best regards,
He
what if I’m trying to read previous solution from a file? I use XMLReader but when route has breaks it gives errors