Choosing a solver

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GAMS offers a number of choices to solve a model and the user may switch solvers at their discretion providing they have appropriate licenses. Mechanically, there are several ways to switch

•	One can just before the solve use an option command of the form

Option model type = solver name

where model type is the same model type as that used in the Solve statement and solver name is the name of one of the available solvers.

option lp=bdmlp;

option nlp=conopt;

option MIP=cplex;

•	One can call GAMS with the command line parameter

model type = solver name

as in

gams mymodel lp=bdmlp

When using the IDE this is placed in the GAMS command box in the upper right hand corner as discussed in the Running Jobs with GAMS and the GAMS IDE chapter.

•	One can choose the solver using the file/options/solvers dialogue in the IDE.

•	One can rerun gamsinst.exe or gamsinst.run at any time and alter the choice of default solver.

•	One can generate a list of all solvers and current default solvers in the LST file using the option Subsystems.

The solvers available depends on the license file.