Change parameters

Examples:batchmode, callback, fixanddive, gc_pwl_func, lp, lpmethod, mip2, multiscenario, params, sensitivity, workforce_batchmode

This section illustrates the use of Gurobi parameters. Exampleparamsreads a MIP model from a file, then solves the model using four different values of theMIPFocusparameter, running for five seconds per value (MIPFocuschooses the high-level strategy that the MIP solver uses to solve the problem). It then chooses the parameter value that produced the smallest MIP gap, and continues solving the model until it achieves optimality.

The mechanics of setting a parameter are quite simple. To set theMIPFocusparameter in C, do the following:

error = GRBsetintparam(modelenv, "MIPFocus", i);

In C++:

m->set(GRB_IntParam_MIPFocus, i);

In Java:

m.set(GRB.IntParam.MIPFocus, i);

In C#:

m.Parameters.MIPFocus = i;

In Python:

m.Params.MIPFocus = i

We should add one quick comment about how parameter settings propagate between different models. When we set theTimeLimit在模型参数,然后做一个警察y of that model, the parameter setting is carried over to the copy. When we set theMIPFocusparameter on the copy, that parameter change has no effect on the other copies, nor on the original model.