Questions tagged [coin-or]

For questions relating to the Computational Infrastructure for Operations Research (COIN-OR).

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Detect presolve status in pulp model

Hi I am running a model using pulp CBC and have few constraints in the model that may make the model infeasible if wrong input is given to the model. I can see while my model runs that in case of ...
Bhavya Budhia's user avatar
2 votes
1 answer
104 views

Structuring an MINLP solver

Folks, I am working on a project in which I have to code some C++ algorithms for smooth MINLPs. Such algorithms are Extended Cutting Plane, Extended Supporting Hyperplane, and Outer Approximation. I ...
Matheus Diógenes Andrade's user avatar
7 votes
1 answer
542 views

Using CBC CLI Arguments in Pyomo

I am currently using the cbc solver with Pyomo opt = SolverFactory('cbc') opt.solve(model) How can more options for Cbc be used,...
Athena Wisdom's user avatar
3 votes
0 answers
92 views

Extract/Inject Solutions (orig problem-space) during Search in MILP -> CoinOR Cbc

Task / Goal I'm considering adding some customized problem-specific local-search component on top of a general-purpose MILP solver (= improvement heuristic). The basic idea is the following: All new ...
sascha's user avatar
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29 votes
4 answers
14k views

What are the advantages of commercial solvers like Gurobi or Xpress over open source solvers like COIN-OR or CVXPY?

I come from an ML background, and occasionally have to dive into the OR world. I am trying to figure out whether I need to purchase a commercial solver license for a certain problem set. In the ML ...
Skander H.'s user avatar
  • 2,139
5 votes
1 answer
273 views

Deterministic termination criteria for CBC

I'm running CBC on problems for which not always an integer solution can be found in a given time, so the command line option sec 120 is set (2 minutes maximum). ...
orange's user avatar
  • 151
3 votes
1 answer
265 views

Manually indicate initial basis for coin-or lp solver CLP

I have a set partitioning formulation with each constraint being an equality constraint to meet the given demand (right-hand side of the constraint). For each constraint, I have a slack and a surplus ...
Sergei's user avatar
  • 31
8 votes
1 answer
735 views

Creating a Continuous Decision Variable between 0 and 1 in Python-MIP Interface

This task appears to be harder than it seems to me. I want to create a continuous variable $x \in [0,1]$. To test this, I did use the open-source Python-MIP interface which uses the CBC-Solver out ...
Georgios's user avatar
  • 1,193
8 votes
1 answer
1k views

How to set a maximum time to improve a solution with Pyomo and CBC

In relation to using CBC via Pyomo: I was wondering if anyone knew if it was possible to set a maximum allowed time to improve a solution, rather than a maximum total time. This way, if you've been ...
domdomdom's user avatar
  • 421
5 votes
2 answers
429 views

Installing COIN-OR solvers in Ubuntu (Azure)

For a side project, I'm looking to install COIN-OR project solvers on a Microsoft Azure Ubuntu VM. (I will be running Pyomo optimization models on this VM as well; using NEOS isn't cutting it.) ...
Ralph's user avatar
  • 371