Using Concert Technology in Java

ILOG CPLEX 11.0 Getting Started > Tutorials > Solving an LP with ILOG CPLEX > Using Concert Technology in Java

Using Concert Technology in Java

Here is a Java application using ILOG CPLEX with Concert Technology to solve the example. An expanded form of this example is discussed in detail in Concert Technology Tutorial for Java Users.

import ilog.concert.*;
import ilog.cplex.*;

public class Example {
  public static void main(String[] args) {
    try {
      IloCplex cplex = new IloCplex();

      double[]    lb = {0.0, 0.0, 0.0};
      double[]    ub = {40.0, Double.MAX_VALUE, Double.MAX_VALUE};
      IloNumVar[] x  = cplex.numVarArray(3, lb, ub);

      double[] objvals = {1.0, 2.0, 3.0};
      cplex.addMaximize(cplex.scalProd(x, objvals));

      cplex.addLe(cplex.sum(cplex.prod(-1.0, x[0]),
                            cplex.prod( 1.0, x[1]),
                            cplex.prod( 1.0, x[2])), 20.0);
      cplex.addLe(cplex.sum(cplex.prod( 1.0, x[0]),
                            cplex.prod(-3.0, x[1]),
                            cplex.prod( 1.0, x[2])), 30.0);

      if ( cplex.solve() ) {
        cplex.output().println("Solution status = " + cplex.getStatus());
        cplex.output().println("Solution value  = " + cplex.getObjValue());

        double[] val = cplex.getValues(x);
        int ncols = cplex.getNcols();
        for (int j = 0; j < ncols; ++j)
          cplex.output().println("Column: " + j + " Value = " + val[j]);
      }
      cplex.end();
    }
    catch (IloException e) {
      System.err.println("Concert exception '" + e + "' caught");
    }
  }
}

PREVIOUS NEXT