Default settings will result in a call to an optimizer that is appropriate to the class of problem you are solving. However you may wish to choose a different optimizer for special purposes. An LP or QP problem can be solved using any of the following CPLEX optimizers: Dual Simplex, Primal Simplex, Barrier, and perhaps also the Network Optimizer (if the problem contains an extractable network substructure). Pure network models are all solved by the Network Optimizer. MIP models are all solved by the Mixed Integer Optimizer, which in turn may invoke any of the LP or QP optimizers in the course of its computation. Table 2 summarizes these possible choices.