[Help-glpk] presolve doubt in MIP problem

[João Campos]

To whom it may concern:

My name is João Campos and I am trying to solve an optimization problem in which all my decision variables are boolean. However, my objective function is not an integer.

In order to solve my problem using the Java API, I enabled the presolver and I used the routine
glp_intopt. I solved the problem using different mip_gap values and there are some questions I would like to make:

-Is it possible to obtain the solution given by the MIP presolver?

-Does the presolve uses the mip_gap value?

-For the same model, for high mip_gap values (0.1; 0.2; 0.3; 0.4; 0.5) the final solutions are the same. Is it because the presolver finds a solution close to the final one so the solver does not take too long to find the final solution?

I would be grateful if these questions could be answered.

Yours faithfully,

João Campos