vrp | A Vehicle Routing Problem solver

We are trying to solve a VRP with Optaplanner. The score calculation runs via constraint streams.

Now I have two vehicles (A and B) and want to schedule two jobs (J1 and J2). The construction heuristic (FIRST_FIT_DECREASING) schedules J1 to A and J2 to B, what is correct so far.

Now the two jobs also have an attribute "customer", and I want to assign a penalty if the customer of the two jobs is the same but the vehicles are different.

For this purpose, I have created a constraint in the ConstraintProvider that filters all jobs via groupBy that have the same customer but different vehicles.

If I now switch on the FULL_ASSERT_MODE, an IllegalStateException occurs after scheduling J2, because the score that is calculated incrementally is different from the score for the complete calculation. I suspect this is because the VariableListener, which recalculates the times of the jobs, only tells the ScoreDirector about a change to Job J2 for my shadowvariables and therefore only changes the score part that is related to it.

How can I tell Optaplanner that the score for J1 must also be recalculated? I can't get to job J1 via the VariableListener to tell the ScoreDirector that the score has to be changed here.

Or does this problem require a different approach?

I've recently started learning and implementing services using AWS services. So, I guess I'm missing some small steps which I can't figure it.

I'm trying to implement the following diagram using the Cloudformation template. Everything is working fine unless. The Lambda and SQS queue are subscribed to the SNS topic successfully. Whenever a file is stored at the bucket, or even when I publish a message to the SNS topic manually, the lambda function is triggered successfully, but the message is not published to the SQS queue. I've also added the AWS::SQS::QueuePolicy to allow SNS to send messages to SQS, but it still does not work.

template.yml:

I am trying to solve a VRP using OR-tools in python. What i want to do is a vehicle that does multiple routes between a depo and pick-up destinations. It should pick items until its capacity is maxxed, go to depo and drop off and then continue with this until all items are picked.

I have searched the web and couldn't find anything. so i tried to combine the examples on OR-tools VRP without luck. So i wonder if there are any similar projects that can inspire.

How does one get googleortools to give back the actual cost of a vrp? This example only returns distance and loads but if I add more cost elements I would like it to show me cheapest outcome. https://developers.google.com/optimization/routing/cvrp

Thanks.

I'm currently using Python and the Google-Or-Tools to solve an VRP problem, that I am not sure how exactly to model. (If someone has a solution with another library/tool, absolutely interested as well)

Problem Statement:

I have basically the classical CVRP problem also described and modelled on the documentation page, but with one addition. So the basic CVRP problem is, I have a depot where cargo is loaded and vehicles start from / end at. Also I have locations where goods are to be delivered to, e.g. they have a demand. Now the addition is, that I not only dropoff goods at the specific locations but also want to pickup goods at the same locations, and eventually dropping them off at the depot again.

Since it is possible for a location to have more goods to pickup than to dropoff, I need to explicitly check this, too ... but I can't find a way so far to do this.

Example: So say I have one Depot node 0 and two location nodes (A,B).

• At location A I need to dropoff 10 units and pickup 11.
• At location B I need to dropoff 10 units and pickup 9.

Now for a vehicle with max capcity 20 the possible solution would be:

• 0 --> B --> A --> 0

First visiting A and then B would not work, since it would violate the capacity constraint in A.

What I've tried:

So to consider the basic dropoff capacity constraint I have the standard

I need to use VRP and take into account that a client wants to either have a pick-up or a delivery. I know VRPB satisfies these requirements but that waits until the truck is empty before picking up from clients.

Is the VRPC able to deal with a negative demand? Which would make it a delivery.

I'm trying to use OR-Tools' Routing Solver to solve a Multi Trip Capacitated VRP. What I need is

• one depot, route starts and ends here.
• one unloading location (different from the depot)
• set time window and demand for each node

So the vehicles should pick up the goods from each node until the capacity is filled. Then go to "unloading location", unload all their weight and keep collecting the demand from nodes until a time limit is reached or all the goods are collected. Then return back to the depot.

CVRP Reload Example seems very close but in my case, at the end of the route vehicles should visit the unloading location before the depot. In other words a vehicle can not go to the depot (starting, ending location) with load.

Example:

I'm using OR-tools VRP to create delivery routes. I have distance as a dimension, a dimension to constrain the number of delivery points per route and my code is very similar to the guide shared in https://developers.google.com/optimization/routing/vrp

The issue I have is that when using SetGlobalSpanCostCoefficient as below, the resulting routes have very short distances from the depot to the first delivery point and from the last delivery point to the depot, but instead, the distances between delivery points is high. Instead, when not using this SetGlobalSpanCostCoefficient the routes have very low distances between delivery points but the distance from and to the depot are higher.

I am struggling running a command using spawn on ubuntu. I am using vrp-cli module written with Rust, here is the code where i am trying to pass few arguments into spawn and run the command: