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
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0answers
43 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
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1answer
80 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 ...
3
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1answer
65 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
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2answers
110 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
134 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
50 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
67 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
194 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
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1answer
129 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
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2answers
121 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
100 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
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1answer
116 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
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1answer
155 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 ...
5
votes
1answer
247 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 ...
14
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2answers
215 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
134 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
435 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
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0answers
59 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
633 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 ...
17
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3answers
575 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
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0answers
63 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
239 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 ...
8
votes
1answer
534 views

Incorrect solution for Vehicle Routing Problem in or-tools

I am trying to understand how the Vehicle Routing Problem is solved in OR-Tools. Using the example given here, I have tried to solve the following distance matrix with 9 separate vehicles: ...
7
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1answer
135 views

Program can't stop when using callback of usercut in CPLEX to solve a branch-and-cut problem

When I tried to use Java to call CPLEX and use callback functions to solve a VRP problem with branch-and-cut, some problems emerged. I took out the subtour elimination constraint from the original ...
11
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2answers
160 views

Difficulties with finding equivalent problem on literature

I'm working with a sort of pickup delivery problem right now. We need to assign vehicles to routes and requests to those vehicles. Each request has its due date, client and may be delivered in one of ...
9
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2answers
128 views

CVRP With Unconstrained Fleet Size: Upper Bound on Optimal Fleet Size

Given a CVRP where the number of trucks is not constrained, is there an upper bound on the number of trucks used in an optimal solution in terms of number of customers, some distances, capacities, and ...
9
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3answers
234 views

Vehicle routing benchmark instances

I recently started working on the classical split delivery vehicle routing problem (SDVRP). I appreciate if someone could let me know where to download benchmark instances for this problem? I am also ...
11
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5answers
713 views

What is the following VRP?

I am researching a Vehicle Routing Problem for a safety insurance company that provides roadside assistance. The company does not have a depot, as in classical VRP, and has a set of heterogeneous ...
23
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6answers
1k views

How to compare two different formulations of a problem?

I somewhat know how to compare two MILP formulations of a problem that both use the same set of decision variables (as in the classical MTZ vs DFJ formulations of the TSP). I was wondering how two ...
21
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5answers
977 views

Solving pricing problem heuristically in column generation algorithm for VRP

In the set covering/column generation approach for the VRP (Balinski and Quandt (1964), or e.g. this tutorial), the basic idea is: Generate some routes. Solve the set covering problem using those ...
9
votes
1answer
232 views

Stochastic VRP: Sources of uncertainty and modeling approaches

In one of the archived research topics of mine, I tried to model and solve SVRPs using Multiple Tandem Queues. I have two related questions: What are the sources for uncertainty in Stochastic VRPs? ...
9
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1answer
94 views

Two-commodity flow formulation for an asymmetric cost VRP

The two-commodity flow formulation is introduced by Baldacci et al. (2004). It is known for its good performance and providing a tight lower bound. I searched the literature, but couldn't find any ...
10
votes
2answers
192 views

Fast validation of time windows in a routing problem

When solving a routing problem with time windows, unless you go for the arc-based math program that describes it, you have to check time windows "manually." For example, generating routes with any ...
9
votes
1answer
145 views

Capacitated VRP-TW: Gehring & Homberger instances

I am trying to benchmark our vehicle routing solver against Gehring & Homberger instances. However, I got bit puzzled by the route duration constraint (maximum driving / maximum working time). In ...
17
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6answers
2k views

List of Implementations for common OR problems

For the TSP there famously is the concord solver (http://www.math.uwaterloo.ca/tsp/concorde.html) which is argubly the fastest exact solver for the TSP. There are many other problems that also show ...
21
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5answers
389 views

Solving ATSP problem for large-scale problem

I want to solve the Asymmetric TSP for a large-scale problem for an industrial application where the company cannot buy a commercial software license. For their applications, it is very important to ...