ILOG CPLEX 11.0 User's Manual

Choosing an Optimizer for Your LP ProblemILOG CPLEX offers several different optimizers for linear programming problems. Each ofthese optimizers is available whether you call ILOG CPLEX from within your ownapplication using Concert or the Callable Library, or you use the Interactive Optimizer.The choice of LP optimizer in ILOG CPLEX can be specified through a parameter, namedRootAlg in the C++, Java, and .NET APIs, CPX_PARAM_LPMETHOD in the Callable Library,and named lpmethod in the Interactive Optimizer. In Concert Technology, the LP method iscontrolled by the RootAlg parameter (which also controls related aspects of QP and MIPsolutions, as explained in the corresponding chapters of this manual). In this chapter, thisparameter will be referred to uniformly as LPMethod.The LPMethod parameter sets which optimizer will be used when you solve a model in oneof the following ways:◆◆cplex.solve (Concert Technology)CPXlpopt (Callable Library)◆ optimize (Interactive Optimizer)The choices for LPMethod are summarized in Table 9.1.Table 9.1 Settings of the LPMethod Parameter for Choosing an OptimizerSetting ofLPMethod MeaningSee Section0 Default Setting Automatic Selection of Optimizer on page 1731 Primal Simplex Primal Simplex Optimizer on page 1742 Dual Simplex Dual Simplex Optimizer on page 1733 Network Simplex Network Optimizer on page 1744 Barrier Barrier Optimizer on page 1745 Sifting Sifting Optimizer on page 1746 Concurrent Dual,Barrier, and PrimalConcurrent Optimizer on page 175172 ILOG CPLEX 11.0 — USER’ S MANUAL