Questions tagged [cbc]

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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
4 votes
2 answers
1k views

Which solvers should I use to solve large, but extremely sparse LP problems with 100-500 thousand variables?

I would like to solve the following type of LP problems: where M and N are very large numbers, they are on the order of a few hundreds of thousands and tens of thousands, respectively. As is clear ...
TobiR's user avatar
  • 143
2 votes
0 answers
65 views

How to rewrite a constraint with sum of convex and concave components to satisfy DCP rule?

suppose that decision variable is X with N dimensions, and one type of the constraint is ...
Allen Zhang's user avatar
1 vote
1 answer
290 views

How to save log file from pulp , log including algorithms used by the solver?

How to save log file from pulp , log including algorithms used by the solver ? while this is printed in the python IDE console, looking to save it as a txt file .
21vs's user avatar
  • 471
0 votes
1 answer
141 views

Pyomo.solvers on anaconda mac Ventura 13.0.1 (22A400)

I am facing difficulties to install pyomo.solvers for anaconda I do need glpk cbc ipopt for my anaconda I tried the following ...
Optimization team's user avatar
3 votes
1 answer
591 views

How do I turn off preprocessing in pulp?

there is an inbuilt preprocessing in CBC solver , which affects the optimality of my solution , I get the optimal output by turning this off in command prompt . How do I turn this off using pulp ?
21vs's user avatar
  • 471
6 votes
1 answer
519 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
142 views

Pyomo: Compute IIS, remove corresponding constraint and resolve

I am using pyomo together with a bunch of solvers (gurobi, cbc, etc.). I am able to compute the IIS (with gurobi, not cbc), and write it in a *.ilp file. What I ...
Meth's user avatar
  • 424
7 votes
1 answer
892 views

Problem is infeasible with Gurobi, feasible with cbc (but can't access objective value)

I am solving a MILP with cbc and gurobi (via pyomo). Gurobi states that the model is infeasible. As to cbc the solver status states that a feasible and optimal solution is found, but then it fails to ...
Meth's user avatar
  • 424
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
  • 446
2 votes
0 answers
215 views

Pyomo Trouble - Number of Constraints in Output is 0 When It Should Be > 5000

I have an MILP program written in Pyomo and I am using CBC as a solver. Below is a description of my problem: The model works fine when it is run on my local computer The output is the following in ...
Devon Elizabeth's user avatar
4 votes
1 answer
122 views

CBC stalling after approximately 10 seconds

I'm using CBC with PuLP to solve a small unit commitment problem. I'm finding that with certain combinations of input parameters, CBC simply stalls. With other input parameters, it solves, usually ...
Daniel's user avatar
  • 41
6 votes
0 answers
222 views

Provide basic solution to CLP

I'm using Pyomo to formulate an LP with approx 500,000 constraints and 200,000 decision variables. The LP is solved using CLP. Some instances fail to return even a feasible solution after many ...
Arjan Dijkstra's user avatar
5 votes
1 answer
433 views

Best way to solve an allocation problem

I have the following problem: I have products with different attributes (price, weight, category) and I have a list of clients. Every client has an "affinity value" with every product, the ...
RenanSchwyz's user avatar
4 votes
1 answer
258 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
  • 141
3 votes
1 answer
173 views

Pyomo CBC 1.#j error

I am using to solve my model Pyomo/CBC combination. But rarely, CBC Gap shows 1.#j and pyomo generate an error. Hence, it doesn't get solution. How can I solve this problem? Screen output: ...
kur ag's user avatar
  • 805