Questions tagged [vehicle-routing]

For questions related to optimization problems for routing vehicles through a set of nodes, especially the vehicle routing problem (VRP) and its variants.

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5
votes
2answers
153 views

Asymmetric time-constrained capacitated vehicle routing problem

I am trying to add some more constraints to the flow-based ADVRP model in Almoustafa et al. (2013)1 (pp.4). The mentioned model caps the travel distance, while I cap the travel time. Let $U$ represent ...
2
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2answers
87 views

OR-Tools: Partial Solution ignored due to “unknown rate is too large”

With SetHint() from the OR-tools linear solver I am trying to pass a feasible solution to my problem. But I receive the following warning: ...
2
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2answers
107 views

Trouble with optional nodes in a VRP model using Gurobi for python

I am currently working on a VRP problem where the vehicles are electric. This means that I have range restrictions, and charging stations as nodes which are optional to visit. In my model I have the ...
3
votes
1answer
64 views

Clustering problem involving multidepots and customers requiring commodities located exclusively in an specific depot

I'm trying to solve a clustering problem that's similiar to a VRP Pickup and Delivery problem with multiple depots and customers. Each customer demands a commodity that is exclusively found on one ...
3
votes
1answer
47 views

How to assign task, resources to trips

In a scheduling problem I want to assign the resources to tasks, each task has earliest start date, latest start date and duration. Also each resource has fixed number of available hours in a day. The ...
1
vote
1answer
98 views

Roulette mechanism with ALNS

I found in the literature that Adaptive Large Neighborhood Search (ALNS), which uses a roulette mechanism to select the best-performing operators, is the most efficient method. However, other ...
4
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1answer
113 views

How to improve the solution in ALNS metaheuristic

I am solving the CVRP with Adaptive Large Neighborhood Search (ALNS) . I used the following construction operators: GreedyInsertion and ...
1
vote
1answer
113 views

Why some decision variables don't get values in Cplex?

I use this code in the cplex and don't know why some decision variables don't get value, I attach my code below. I don't know my model is wrong or my code? I haven't error in the code but have some ...
4
votes
1answer
98 views

Incomplete initial solution for capacitated vehicle routing problem

I am solving Capacitated Vehicle Routing Problem (CVRP) with Adaptive Large Neighborhood Search (ALNS) metaheuristic. I start my algorithm with a random initial solution, but the solution I get is ...
2
votes
3answers
500 views

Random solution for capacitated vehcle routing problem (cvrp)

I'm currently solving the capacitated vehicle routing problem (cvrp) with the approached methods (metaheuristics). In order to do this I have to build a random initial solution. My question is when we ...
3
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1answer
136 views

Calculate the average of the objective function values ​resulting from metaheuristics after a defined number of executions

I am trying to solve the capacitated vehicle routing problem (CVRP) with the ALNS metaheuristic. To test the performance of my algorithm I run it 10 times and I want to calculate the average of the ...
1
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1answer
75 views

Difference between Solomon's problem instances

I am in the process of solving the VRP and I have a set of Solomon test instances to test my program. I actually found a test set with C101, C102, ..., ...
3
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1answer
143 views

VRP book recommendations

I am looking for a book recommendation on the VRP and variants. I am encountering VRP-like problems more and more in my work and would appreciate a reference.
2
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1answer
149 views

Working with large models

I am working with a variant of TSP, number of nodes that I need to test are in between 2500 to 3000 nodes, I am using docplex for modelling, I have a 8 gb Ram but it gets filled with only 400 nodes. ...
3
votes
1answer
78 views

To calculate the time needed for a vacuum robot to cover whole area

A vacuum robot runs on randomized direction when it is operating in a room. I want to know how long it takes to fully cover the whole area (or at least most part of the area) with given information: ...
2
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0answers
156 views

modify pickup and delivery problem to only delivery scenario in google OR-tools

I am using Google OR Tools for solving the capacitated vehicle routing problem.I want to implement optimization solution for delivery problem.For example there is one storage location which load all ...
7
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0answers
272 views

OR-TOOLS : delivery node with multiple possible pickup nodes

I am using ortools to model a VRP with pickup and delivery constraints, where pickups can be done at different nodes. For example, if node A has a demand, it must be picked at node B or C. Here is how ...
6
votes
1answer
184 views

OR-TOOLS : is it possible to partially fulfill a demand?

I am working on a vehicle routing problem with or-tools. Is it possible to partially fulfill a demand? I know it is possible to drop nodes with the disjunction constraints. But in this case, a node is ...
2
votes
1answer
159 views

VRPTW implementation

Does anybody have an example of the vehicle routing problem with time windows (VRPTW), implemented on Python with CPLEX library, AMPL, or MiniZinc? So far I've looked into ...
6
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0answers
57 views

Estimating multistop routing costs

In many OR problems, it is sometimes a good idea (or necessary) to relax routing constraints. An example of this occurs in the classical facility location problem, where a warehouse can send out a ...
1
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0answers
96 views

How to develop a vehicle routing optimization package? [closed]

I would like to know how vehicle routing software optimizes routes? In demos of this software, they provide the optimal (or a good) route in just a few seconds or minutes with several nodes (maybe 50 ...
4
votes
1answer
120 views

How to represent time window as constraint in a vehicle routing problem

Hi I am trying to solve a vehicle routing problem using Tabu search, I have successfully completed implementation of constraints for CVRP by giving penalties to objective function , how do I implement ...
6
votes
2answers
386 views

Branch and Price Algorithm

Can branch and price be a good solution approach for a routing problem with min-max objective function? For example, minimizing the max length of any vehicle route in a VRP. In the literature, I haven'...
4
votes
1answer
172 views

Column Generation algorithm

I want to solve a VRP with a column generation algorithm. The objective of the problem is makespan minimization. but there is a point in calculating the arrival time of the vehicle in each node. the ...
6
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1answer
166 views

Asymmetric vehicle routing benchmark instances

Is there a standard set of asymmetric capacitated vehicle routing problem (ACVRP) benchmark instances similar to CVRP (http://vrp.galgos.inf.puc-rio.br/index.php/en/)? The only thing I found were a ...
5
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0answers
81 views

Column generation approach for CVRP

I want to use a column generation based heuristic to solve a capacitated Vehicle Routing Problem. I know the basics of the algorithm but I don't have much experience in coding. is there any code about ...
3
votes
1answer
117 views

A Question on A tutorial on column generation and branch-and-price for vehicle routing problems by Dominique Feillet

I am reading A tutorial on column generation and branch-and-price for vehicle routing problems by Dominique Feillet to learn the column generation approach, but I have a problem. in section 3.3 ...
5
votes
1answer
208 views

Column Generation algorithm for vehicle routing problem

I want to solve a VRP with a column generation algorithm. The objective of the problem is makespan minimization. In more detail, I want to minimize the arrival time of the last vehicle in the depot. I ...
5
votes
0answers
81 views

Are there any good models for min-max vehicle routing problem?

I am trying to model a min-max VRP problem with multiple delivery vehicles and I have come up with a model using branch and cut but I do not think it is strong enough as it takes lot of time to ...
6
votes
1answer
96 views

CVRP with vehicles blocking each other

I have a standard CVRPTW (capacitated vehicle routing problem with time windows). The instance is given by a (not complete) graph $G$ with weighted $w$ directed edges $e \in E$, and I have a limited ...
4
votes
1answer
149 views

Is it possible to solve VRP using OR-Tools CpModel, instead of RoutingModel?

Is it possible to solve VRP using OR-Tools CpModel, instead of RoutingModel? I want to do synchronized VRP, which is combining vehicle routing and scheduling constraints
5
votes
2answers
212 views

Priority List Constraint

I used the Vehicle Routing Problem example that has the objective of minimizing total distance traveled for each vehicle. Suppose that each order to pick up for each vehicle at each node has a ...
2
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2answers
175 views

How to use tight upper and lower bounds to get to the optimal value via branch and bound?

I have algorithms that get me a tight upper (UB) and lower (LB) bound to a maximization binary integer program (a routing problem). My formulation is non-compact and requires the addition of sub-tour ...
1
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0answers
69 views

Fixed cost associated to SlackVar(waiting time cost) [CVRPTW]

I'm modeling a CVRPTW with some features: Each type of vehicle has a cost per km and a fixed cost per trip. To calculate these costs, I am using these methods for this: ...
4
votes
1answer
150 views

Adding a hard and soft upper bound constraint of number of locations to visit (VRP)

I went through the Vehicle Routing Problem example and was able to replicate it. On the example, there is a constraint added for vehicle maximum distance as shown below: ...
5
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3answers
206 views

Problem with binary decision variable constraints in VRP

I would like to create non-linear violation costs in my VRP. I already created my whole VRP with time windows in which I have these decision variable: ...
6
votes
1answer
247 views

Advanced Heuristics for MIP vehicle routing problem in PuLP

I am currently trying to speed up an MIP. An approach I was considering was to implement a cut callback heuristic with PuLP (one which rounds relaxed integer variables greater than .9 to 1). ...
4
votes
2answers
133 views

VRP app as a Minimum Viable Product

In this post, Geoffrey De Smet and EhsanK pointed out the opportunities of VRP variants (e.g. mixed pick up and deliveries). If I want to build a Minimum Viable Product (software as a service app). ...
2
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0answers
111 views

Montoya et al. 2017 benchmark Results

I am testing Montoya et al. 2017 dataset and trying to replicate the Result from this paper The electric vehicle routing problem with capacitated charging stations. I am unable to replicate the exact ...
4
votes
1answer
146 views

VRP benchmark instances with charging stations

Are there any benchmark instances for VRP with charging stations? I also have various delivery points with charging stations in the city(Multiple Vehicles). How can I compare my formulation?
4
votes
1answer
280 views

Solving vehicle routing problem in java

I am trying to solve vehicle routing problem in java and I am looking for libraries for the same. I did a POC using google or-tools and it seems to be solving all my use cases. I would like to know if ...
6
votes
1answer
497 views

Solution time out for VRPTW in or-tools

I am experimenting around with or-tools and somehow I can't get a solution for the VRPTW problem for any of the instances I have tested from Gehring & Homberger ...
16
votes
3answers
321 views

Customer clustering to solve very large-scale VRPs

I am looking for references that used customer aggregation to solve large-scale Vehicle Routing Problems. By aggregation, I mean clustering the customers together and representing them with one node ...
9
votes
1answer
239 views

How to remove or replace sub tour elimination constraints in the VRP variant models?

In many of vehicle routing problems variant (VRP), which can be formulated using MIPs, to avoid creating sub tour, we need to use sub tour elimination constraints (SEC). One of the known SEC is (I ...
5
votes
1answer
881 views

VRP package for R

I work almost exclusively in R and Rstudio, and have found it to be an excellent ecosystem for data analysis and OR, including discrete event simulation, Monte Carlo simulation, MILP, and the ...
5
votes
0answers
74 views

Understanding HardRouteConstraint

I am trying to understand the route constraints in jsprit. While I got the concept of HardActivityConstraint, I am unable to have clarity on HardRouteConstraint. Can someone, preferably with a simple ...
14
votes
2answers
663 views

Obtaining optimality gaps when using hybrid exact-heuristic approaches to vehicle routing problems

I'm starting to read about column generation-based approaches to vehicle routing problems (VRP). Let's say that I want to solve very large instances of an intricate VRP, I'm not looking to always ...
25
votes
5answers
1k views

What's the current status of the Vehicle Routing Problem in the logistics industry?

After a bit of reading I think I've been able to conclude that state-of-the-art VRP can get solutions for 100~500 stops. My question is around how this actually affects logistics (like Amazon for ...
8
votes
0answers
70 views

Multiple shipments with FILO order

I am trying to solve a problem statement with the help of jsprit. There is a depot. Identical items need to be delivered or picked up. An item can have two states: Bad or good. Bad items need to be ...
13
votes
1answer
285 views

Two-stage $k$-means clustering

The problem I am facing is clustering problem, needed for a Vehicular Routing Problem (VRP) I'm tackling. It is a heterogeneous VRP with Time Window (TW) and a capacity utilization constraint, i.e. a ...