Questions tagged [cbc]
The cbc tag has no usage guidance.
16
questions
0
votes
0
answers
70
views
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 ...
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 ...
- 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 ...
- 21
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 .
- 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 ...
- 1,277
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 ?
- 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,...
- 243
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 ...
- 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 ...
- 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 ...
- 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 ...
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 ...
- 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 ...
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 ...
- 53
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). ...
- 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:
...
- 805