Switching within a modeling language

How you migrate from a modeling system depends on which modeling system you're using. With the solver-independent systems — AIMMS, AMPL, GAMS and MPL — migrating is extremely easy: you simply need to install a license, set the solver to Gurobi, and set your parameters, if any. You can find detailed instructions below.

With the single-solver systems — OPL and Mosel — you will need to migrate your existing model code. Since these are both algebraic modeling languages, this migration is straightforward. You can read more about switching from OPL on our Switching from OPL webpage. Contact us for additional details.

Note: If you are using CPLEX or XPRESS outside of a modeling language please visit our switching from CPLEX page or our switching from XPRESS page.

This page covers three topics:

  1. Obtaining a Gurobi license
  2. Selecting Gurobi as your solver
  3. Converting parameter settings

Obtaining a Gurobi License

If you are using AMPL, we can sell you a license or provide an evaluation copy directly. Simply contact us at sales@gurobi.com. If you are using AIMMS, GAMS or MPL, you'll want to contact them directly and ask for a Gurobi License.


Selecting Gurobi as your solver

Depending on the modeling language, you will use either an IDE (AIMMS and MPL) or a change a line in the model file (AMPL and GAMS).

Modeling Language Change Required
AIMMS Select Gurobi via menu: Settings > Solver Confirguation
MPL Add Gurobi via menu: Options > Solver Menu
AMPL In model file, add: option solver gurobi_ampl;
GAMS In program file, add either: Option LP = Gurobi; or Option MIP = Gurobi;

If you do run into any issues or have any questions, we are happy to assist our academic users via our Gurobi Google Group and our commercial customers and prospective users via support@gurobi.com.


Converting parameter settings

The final step is to set the Gurobi parameters. Below is a table with information on where in each modeling language you can go to set the parameters. In addition, our switching from CPLEX™ and switching from XPRESS™ pages contain a detailed list of common parameters used by each of those engines, along with their corresponding Gurobi equivalent.

Modeling Language Action Required
AIMMS First, in menu select Settings > Project Options; second, in Option Tree select Specific Solvers > Gurobi then set the parameters via the GUI.
MPL First, in menu select Options > Gurobi Parameters then set the parameters via the GUI
AMPL In model file, add: option gurobi_options 'presolve 2';
GAMS Use command-line flags, options file or IDE

Additional information on migrating models can also be found in our Migrating an existing model to Gurobi file.


Conclusion

Switching to Gurobi from within a modeling language can be done relatively quickly and with no changes required to your model. If you do run into any issues or have any questions, we are happy to assist our academic users via our Gurobi Google Group and our commercial customers and prospective users via support@gurobi.com.