Questions tagged [or-tools]

Questions related to or-tools, Google's open-source software suite for optimization

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OptionalIntervalVar enforced but not working OR-TOOLS

I'm using OptionalIntervalVar and then maximizing the starts. The optimal solution is not affecting the other variables that creates the ...
Diego R. Troncoso's user avatar
6 votes
0 answers
161 views

Modelling issue with precedence constraint in OR-Tools

I'm trying to solve an RCPSPDc model It is infeasible, although Ilog Cplex solves it, so I think I have a modelling issue. I have more constraints but the precedence is the one that makes it ...
Diego R. Troncoso's user avatar
6 votes
0 answers
89 views

Data Formulation for Mixed-Integer-Programming Models

Until now, I have used the Gurobi, CPLEX and OR-Tools (GCO) interface to formulate mixed-integer-programming models. Recently, I have discovered MiniZinc and want to utilize it to formulate big ...
Georgios's user avatar
  • 1,193
5 votes
1 answer
121 views

Numerically stable way to optimize a lexicographical preference between two objective functions?

I am solving a mixed-integer program whose decision variables are $x \in \{0, 1\}^n$ and $y \in \mathbb{R}^m$, where $0 \leq y_j \leq u_j$ for constant upper bounds. My primary objective function is ...
Max's user avatar
  • 534
4 votes
0 answers
902 views

Google-OR tools vs Pyomo and other commercial Solvers for solving a simple maximum flow problem

I have implemented a Pyomo model for solving maximum flow problem as a subroutine of an algorithm. However, the approach does not scale very well because Pyomo does not provide a very good way to re-...
Pia MiA's user avatar
  • 392
4 votes
0 answers
106 views

Modelling issue with rcpsp and boolean expressions

I'm trying to solve an RCPSPDc problem in OR-Tools with CP-SAT solver. In my RCPSPDc model (with discount rate) i want to set this objective: $$\max_{s}\sum_{j\in J}\text{profit}_{j}\cdot \frac{1}{(1+...
Diego R. Troncoso's user avatar
3 votes
0 answers
43 views

Adding synchronisation constraint in Prize-collecting VRPTW

I am solving a Prize Collecting VRPTW. In my problem, each node represents a visit that needs to be made within a certain time window, and the "prize" for each node is the time spent at the ...
orman's user avatar
  • 33
3 votes
0 answers
273 views

Or-tools : CVRP multiple time window with multiple location

I am using or-tools to solve a CVRP with multiple time window, and multiple location. Meaning that a customer can move during the day. I can't achieve to add constraint like if i deliver the customer ...
Cyprien's user avatar
  • 31
3 votes
0 answers
183 views

Can Pyomo be linked with Google's GLOP or CP-SAT solvers?

Pyomo can be linked with several solvers Open source and commercial ones. I was wondering if Pyomo can be linked with Google's GLOP or CP-SAT solvers?
Optimization team's user avatar
3 votes
0 answers
547 views

Incorporating OR-Tools in a CMake Project

I'm trying to incorporate or-tools into my cmake project. I've tried some of the suggestions given by the project maintainers, who give a few different ways to integrate or-tools in the readme and in ...
Connor's user avatar
  • 431
3 votes
0 answers
448 views

Circuit constraints in ortools

I am looking to assign tasks to people. Each successive task should be started after the first one is finished and should be started at the same location as the preceding task. While the time ...
Srikanth Shastry's user avatar
3 votes
0 answers
112 views

Availability of library for solving generalized network flow problems

I need to solve a large-scale generalized network flow problem. For reference, it is a pure network-flow model with the exception that arcs have a positive coefficient applied to flow on them. In my ...
Suleyman Karabuk's user avatar
3 votes
0 answers
320 views

Add Variables in Bulk for ortools

I am using the Python ortools to solve large LPs where the number of variables and constraints are in the hundred thousands ($10^5$). Surprisingly, it takes longer ...
Zachzhao's user avatar
  • 131
3 votes
0 answers
110 views

Production planning for a video game economy

I'm a software developer who likes to play a video game that has a complex economy. I realized that the type of problem I'm trying to solve mimics real life operations research problems, and I am ...
0x1F602's user avatar
  • 139
3 votes
0 answers
50 views

High-mix manufacturing capacity

I'm not an expert in OR but I would like to determine what is the maximum manufacturing capacity of a plant (or how much a plant can produce of mix products). Each person in the plant has a known set ...
Otmane Zizi's user avatar
3 votes
0 answers
192 views

Power of variable or tools

I'm working with OR Tools in Python and I need to define the objective function an expression of the variables. In particular, the objective function is $$\frac{c_j}{1.7^{s_j}}$$ with $c_j$ ...
Clopen's user avatar
  • 131
2 votes
1 answer
106 views

Rearrange 'x' piles of items into eight possible locations/bins based on item colour and length

I have an optimisation problem that I believe is a variant of the 'bin packing problem with precedence', but I'm unsure of if that is the correct paradigm to work with and I'm not having a huge amount ...
Jon Knott's user avatar
2 votes
1 answer
142 views

Control load per trip in multi trip VRP in ORTools

I have implemented multitrip VRP in ortools (To be specific, solved CVRPTW with virtual depots). Maximum number of trips per vehicle is limited to 2. I want to put a hard constraint that load carried ...
mufassir's user avatar
  • 201
2 votes
0 answers
191 views

Big M and convergence of LP to IP

I have been working on an applied problem with Big M constraints (due to several security issues in the company, I cannot write the formulation I am working on). While solving with a partially LP-...
Applicable Math's user avatar
2 votes
0 answers
138 views

Multiple Depot/Crew Office Bus Driver Scheduling Modelling

I'm working on Bus Driver Schedule with multiple add-on constraints that are complex and hence trying to figure out how this can be achieved. Reference of Bus Driver Scheduling using OR-Tools:- https:/...
Brainiac's user avatar
2 votes
0 answers
453 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 ...
Rajith Thennakoon's user avatar
1 vote
0 answers
67 views

Vehicle Routing Problem OR-tools - Distance between solutions / vehicles

I have an alternative problem which I reckon can be solved using OR-tools. For this problem, apart from the distance between nodes within a solution, I also need the distance between the n-th node of ...
Jigeli's user avatar
  • 11
1 vote
0 answers
82 views

How to cmpute IIS using the Or-Tools solver?

I'm trying to solve a MIP using Google Or-Tools, but it's showing that the model is infeasible. I'd like to know if there is a convenient way to analyze which constraint or variable bounds are causing ...
Ying's user avatar
  • 105
1 vote
1 answer
648 views

OR-Tools: Nonlinear constraints?

I have inherited a reasonably simple ortools-based optimizer (Python) with linear relationships that I need to non-linear-ize, and I have no idea how to do that. The relevant part of my problem looks ...
Matthias Urlichs's user avatar
1 vote
0 answers
101 views

Minimizing total number of banners used in the cover buildings problem modelled

I was watching a video about Google OR-Tools where they were solving this cover building problem from Codility challenges using constraint programming. In short, you have a list of building heights, e....
dabadaba's user avatar
  • 111
1 vote
0 answers
378 views

Adding sequence constraints to the assignment problem- Python

This is an online assignment problem and yet can be considered as an assignment problem with a sequence. Assume that workers are coming into the system sequentially and I want to assign a task to them ...
Dr. Turkuaz's user avatar
1 vote
0 answers
303 views

Set Covering and Column Generation

I need some set covering and column generation examples in OR-Tools python. If anyone can provide or direct me to some resources that would be great..!
user3237357's user avatar
1 vote
0 answers
223 views

Modified bus scheduling problem question in ortools

Has been crossposted in stackoverflow. I want to solve the bus scheduling problem using ortools with some minor modifications. In my case, the max number of drivers is known. The modifications I would ...
azal's user avatar
  • 153
1 vote
0 answers
206 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: ...
Luiz Picanço's user avatar
0 votes
1 answer
119 views

Or-Tools:glop or clp to solve a LP

I have a linear programming problem where I use Or-Tools interface in Java for modeling. When using SCIP, I sometimes encounter memory errors and the solving time is relatively long. Later, I changed ...
Ying's user avatar
  • 105
0 votes
0 answers
131 views

Mixed Integer Programming - Model Formulation for A Resource Allocation Problem

There are a number of orders, which needs to be shipped. For each order, there may be 1 to 3 route options. The problem here is to find out the best allocation (combination) of orders among these ...
Jack's user avatar
  • 137
-1 votes
1 answer
253 views

[OR-Tools][CP-SAT] Implement an indicator function in a constraint

Good morning ! I would like to implement this constraint using CP-SAT (see image below). x_i,j is a boolean variable, a and b are given. The problem is that I don't know how to implement the ...
Arthursbr's user avatar
-1 votes
2 answers
149 views

Reformulate this constraint optimization problem such that I do not have to divide 2 variables?

I have a constraint optimization problem as follows: I need to assign $m$ tasks to $n$ days, with $n \geq m$. Each day can host 0 to $m$ tasks. Each task either belongs to type $A$ or $B$. I want to ...
Waldo's user avatar
  • 19