All Questions
40
questions
2
votes
1
answer
217
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 ...
CommunityBot
- 1
3
votes
1
answer
768
views
How to balance the workload of teachers in OR-Tools (maximization of the minimum)
I am very new to optimization and OR-Tools. I am trying to solve a very simple question.
Let's assume that we have $n$ students. Each student needs to be assigned to only one teacher as a supervisor. ...
- 2,865
2
votes
2
answers
1k
views
Cutting Stock Problem : Mixed Integer Programming
I am asked to solve the following problem:
The problem:
You were asked to repair a farm house with sheets of plywood.
You were given thirty sheets of plywood. (each size = 10ft x 10ft)
The house ...
- 2,130
10
votes
1
answer
2k
views
Floating points in OR-Tools
I'm trying to solve an RCPSPDc model (maximizing the net present value instead of a makespan). The objective function is: $\sum\limits_{j \in \text{Tasks}} e^{-\theta\cdot s_{j}}\cdot p_{j}$, where $...
- 2,865
6
votes
1
answer
1k
views
Constraint Programming OR-Tools finding Matrix Combinations
As a similar post of mine Find all Combinations of a Matrix I am trying to find matrix combinations with entries $>0$ meaning for a matrix
\begin{bmatrix}
0 & 1 & 3 \\
5 & 2 & 1 \\
...
- 2,865
2
votes
2
answers
182
views
Mixed Integer Programming: Iterative assignment problem
I have a real world problem, which is analogous to the below toy problem, which I call 'The Movie Theater Problem' (TMTP.)
In TMTP, movie viewers are assigned seats which principally balances two ...
- 2,865
3
votes
2
answers
194
views
Google OR returning different values depending on language
Lately, I have been working on a CP-SAT model for solving multi-resource flexible job shop problems.
I used the code (1) as an inspiration for building code (2) in Python which works well. Then I had ...
- 2,865
1
vote
0
answers
400
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 ...
- 2,865
3
votes
1
answer
612
views
Bin Packing with CP Solver
[ [0,5],
[0,4],
[1,6],
[2,4],
[3,6],
[3,2],
[4,5],
[5,5],
[6,4],
[7,3],
[8,2],
[8,3],
[9,5],
[10,3]]
...
- 2,865
6
votes
1
answer
367
views
Interface for Cbc - COIN-OR
I would like to code some IP/MIP models in python and test them with an open-source solver. As of now, I only know the Cbc - COIN-OR open-source solver.
I have already tried the or-tools interface, ...
- 2,865
4
votes
2
answers
613
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:
...
- 33.1k
1
vote
1
answer
167
views
Non integer linear objective in or-tools CP-SAT
It seems that or-tools' CP-SAT solvers allows for non-integer coefficients in a linear objective expression. Am I correct, or is it just that the solver doesn't check for integrity and rounds the ...
- 2,865
0
votes
1
answer
84
views
how the number of employees affects the married employee scheduling problem
My scheduling problem has a specific pattern of 2 days of work followed by 2 days off. Additionally, there is a week off after every 4 weeks of work. The scheduling matrix (P) has five different ...
- 2,865
1
vote
1
answer
276
views
Are there any hidden differences in OR-Tools' default parameters for a MIP model in Python vs C++?
or-tools-discuss cross post here.
As a disclaimer -- I am very aware that OR-Tools' Python code are just wrappers around their C++ source code. I'm just getting an odd discrepancy between a model ...
- 2,865
3
votes
1
answer
2k
views
Python, Google OR-Tools, OnlyEnforceIf() method
I am trying to solve a basic puzzle by using Google OR-Tools, this is my first try with OR-Tools and I am trying to learn. I completed almost everything and was ready to conclude the program until I ...
- 2,865