ILOG CPLEX 11.0 User's Manual > Languages and APIs > ILOG Concert Technology for Java Users > Choosing an Optimizer > Solving a Single Continous Model

Solving a Single Continous Model

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To choose the optimizer to solve a single continous model, or the first continuous relaxation in a series, use

IloCplex.setParam(IloCplex.IntParam.RootAlg, alg)

where alg is an integer specifying the algorithm type. Table 2.3 shows you the available types of algorithms.

Table 2.3 Algorithm Types for RootAlg
alg 
Algorithm Type 
LP? 
QP? 
QCP? 
0 
IloCplex.Algorithm.Auto 
yes 
yes 
yes 
1 
IloCplex.Algorithm.Primal 
yes 
yes 
not available 
2 
IloCplex.Algorithm.Dual 
yes 
yes 
not available 
3 
IloCplex.Algorithm.Network 
yes 
yes 
not available 
4 
IloCplex.Algorithm.Barrier 
yes 
yes 
yes 
5 
IloCplex.Algorithm.Sifting 
yes 
not available 
not available 
6 
IloCplex.Algorithm.Concurrent 
yes 
yes 
not available 

You are not obliged to set this parameter. In fact, if you do not explicitly call IloCplex.setParam(IloCplex.IntParam.RootAlg, alg), ILOG CPLEX will use the default: IloCplex.Algorithm.Auto. In contrast, any invalid setting, such as a value other than those of the enumeration, will produce an error message.

The IloCplex.Algorithm.Sifting algorithm is not available for QP. IloCplex will default to the IloCplex.Algorithm.Auto setting when the parameter IloCplex.IntParam.RootAlg is set to IloCplex.Algorithm.Sifting for a QP.

Only the settings IloCplex.Algorithm.Auto and IloCplex.Algorithm.Barrier are available for a QCP.

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