Questions tagged [cbc]

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3 votes
1 answer
262 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 ?
  • 459
6 votes
1 answer
201 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,...
3 votes
0 answers
68 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 ...
  • 414
7 votes
1 answer
513 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 ...
  • 414
3 votes
0 answers
87 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 ...
  • 213
2 votes
0 answers
127 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 ...
4 votes
1 answer
94 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 ...
  • 41
6 votes
0 answers
165 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 ...
5 votes
1 answer
319 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 ...
4 votes
1 answer
174 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). ...
  • 141
3 votes
1 answer
167 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: ...
  • 746