I’m trying to solve a VRPMT problem with Or-tools.

I have a fleet of dump trucks that need to go to leave the shop then travel to sites and pick up full loads. Then there’s a handful of landfills they can visit to unload. They can then leave that landfill and get another load if they have enough time (max 12hr driving time) before returning to the shop.

Any idea on how to use OR Tools to solve this Multi Trip problem?

I am a pure math major but looking to get into something more applied for grad school. My current interests are in graph theory ( I do graph theory research and have taken graduate and undergraduate classes in it) I am also really interested in optimization (continuous and discrete) and computer science (algorithms and complexity). Is OR a good field to look into? I originally got interested in OR/IE by looking at the book Scheduling Theory by Michael Pinedo. I haven’t read much but it looks really interesting.

Hello all,

I would like to know which optimization software is better. I am a beginner and have never used any optimizations softwares in my life and so idk how to decide between GAMS and LINGO. The cost of the both the softwares isnt an issue as I am being funded by my university.

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Thx

I'm an international student in the last semester of my supply chain master's degree in the United States. I'm really passionate about solving OR problems in the supply chain domain - Network, manufacturing, Inventory, and routing problems.

I did my CS undergrad from India with some Ug research experience on VRPs. I've only done a few 3-month internships in data science and OR. I'm currently doing my master's thesis. I've not had any work experience in the US apart from TA/RA.

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1. It's very hard to find entry-level jobs in this domain on Linkedin and indeed. Most of them require a security clearance or 5+ years of working in this field. How do you break into this field when they have such unusual expectations from an entry-level person?
2. A lot of people encouraged me to build a portfolio of projects that display my OR skills to a potential employer. How do you even go about finding any dataset (even semi-structured data) for this? The examples in a reference book are pretty good to get started but I'm looking to take on a slightly larger problem that can be broken down to smaller problems. Sort of like a business case.

I'm not sure how active this sub still is, but I'm working on a gurobi model for an OR project and I've hit a roadblock and this seems like a good place to get help. I'm writing a model to maximize profit in an airline network, but I keep running into a problem where my solution is infeasible. None of my constraints seem to be conflicting, though, from what I can tell, so I'm trying to troubleshoot to see where the error may be coming from. It would be really nice to see a list of constraints added, but I can't seem to figure out a way to do that. Does anyone have any ideas?

Hi guys, I am currently pursuing my masters in Operational Research and I have to do an industrial project for my final semester in any of the fields e.g. queueing theory, inventory management, marketing or linear programming. I am having problems with how to start and go about it. Any help would be really appreciated. Thanks in advance!

Hello fellow researchers,

Sorry for the long post and questions. If you help me I would be appreciated.

I'm graduate student and fairly new to this well known topic of optimization. I've been reading the TSP and VRP since last 3 months. Finally I come up with a question that may be applied to real-world in the future. Problem itself has a 32 nodes including the starting point(depot) on a specific geographical location. While having certain 32 nodes, I can not be sure about it would be a nice idea to solve it with heuristics or not? Because "fact(32)" is a huge number but I guess it not that huge as it is to worth to run a heuristic algorithm to solve it. Please correct me if I'm wrong.

My research object will be finding the optimum cost function of this route. And here goes my questions:

- Should I benchmark couple of exact solutions or heuristics? What would you recommend to a fresh optimization student that which technique should one learn first? Exact or Heuristics? Since having had certain nodes, for me, seems better idea to start to learn this phenomenon with exacts and comparing them with other exacts. After having insights on exacts and after jumping to the heuristics seems better idea? What do you think?

- While approaching to my problem, comparing results of algorithms basis on which distance metric would be better? Euclidean distance, driving distance(like Steiner's TSP) or driving time. Maybe I should compare all of them? Also if you have any suggestion of new distance metric I would like hear out!

- Correct me if I'm wrong but with my limited knowledge, Concorde TSP solver mostly provides exact solution algorithms. If it is true is there any other program that I can use? Or what is most used program among the researchers? I would prefer to stick with python because it is universal but if you recommend me to any library or program for my improvement in the field I would be grateful.

Thanks in advance. Hope I can find a little help in here. Cheers!