Solve

Step 11: Create an instance of IloCP

Add the following code after the comment //Create an instance of IloCP

    IloCP cp(model);

You now use the member function IloCP::solve, which solves the problem contained in the model by using constructive search and constraint propagation. The search for an optimal solution in this problem could potentiality take a long time, so you place a fail limit on the solve process. The search will stop when the fail limit is reached, even if optimality of the current best solution is not guaranteed.

Step 12: Search for a solution

Add the following code after the comment //Search for a solution

    cp.setParameter(IloCP::FailLimit, 10000);
    if (cp.solve()) {

The member function IloCP::solve returns a Boolean value of type IloBool. If a solution is found, the value IloTrue is returned.

After a solution has been found, you can use the member functions IloCP::getObjValue and IloCP::domain to examine the solution. The stream IloAlgorithm::out is the communication stream for general output. The code for displaying the solution has been provided for you:

      cp.out() << "Solution with objective " << cp.getObjValue() << ":" << std::endl;
      for (IloInt i=0; i<allTasks.getSize(); ++i) {
        if (cp.isPresent(allTasks[i]))
          cp.out() << cp.domain(allTasks[i]) << std::endl;
      }

Step 13: Compile and run the program

Compile and run the program. You should get the following results:

Solution with objective 357:
H0-masonry-Joe [1: 0 -- 35 --> 35]
H0-carpentry-Joe [1: 170 -- 15 --> 185]
H0-plumbing-Jack [1: 65 -- 40 --> 105]
H0-ceiling-Jack [1: 50 -- 15 --> 65]
H0-roofing-Joe [1: 215 -- 5 --> 220]
H0-painting-Jim [1: 65 -- 10 --> 75]
H0-windows-Joe [1: 250 -- 5 --> 255]
H0-facade-Joe [1: 265 -- 10 --> 275]
H0-garden-Jim [1: 220 -- 5 --> 225]
H0-moving-Jim [1: 275 -- 5 --> 280]
H1-masonry-Joe [1: 35 -- 35 --> 70]
H1-carpentry-Joe [1: 140 -- 15 --> 155]
H1-plumbing-Jack [1: 215 -- 40 --> 255]
H1-ceiling-Jack [1: 105 -- 15 --> 120]
H1-roofing-Joe [1: 225 -- 5 --> 230]
H1-painting-Jim [1: 120 -- 10 --> 130]
H1-windows-Joe [1: 240 -- 5 --> 245]
H1-facade-Joe [1: 275 -- 10 --> 285]
H1-garden-Jim [1: 255 -- 5 --> 260]
H1-moving-Jim [1: 285 -- 5 --> 290]
H2-masonry-Joe [1: 105 -- 35 --> 140]
H2-carpentry-Joe [1: 155 -- 15 --> 170]
H2-plumbing-Jack [1: 175 -- 40 --> 215]
H2-ceiling-Joe [1: 185 -- 15 --> 200]
H2-roofing-Joe [1: 230 -- 5 --> 235]
H2-painting-Jim [1: 200 -- 10 --> 210]
H2-windows-Joe [1: 245 -- 5 --> 250]
H2-facade-Joe [1: 255 -- 10 --> 265]
H2-garden-Jim [1: 235 -- 5 --> 240]
H2-moving-Jim [1: 265 -- 5 --> 270]
H3-masonry-Joe [1: 70 -- 35 --> 105]
H3-carpentry-Joe [1: 200 -- 15 --> 215]
H3-plumbing-Jack [1: 255 -- 40 --> 295]
H3-ceiling-Jack [1: 120 -- 15 --> 135]
H3-roofing-Joe [1: 220 -- 5 --> 225]
H3-painting-Jim [1: 135 -- 10 --> 145]
H3-windows-Joe [1: 235 -- 5 --> 240]
H3-facade-Joe [1: 295 -- 10 --> 305]
H3-garden-Jim [1: 295 -- 5 --> 300]
H3-moving-Jim [1: 305 -- 5 --> 310]
H4-masonry-Jack [1: 0 -- 35 --> 35]
H4-carpentry-Jim [1: 103 -- 15 --> 118]
H4-plumbing-Jack [1: 135 -- 40 --> 175]
H4-ceiling-Jack [1: 35 -- 15 --> 50]
H4-roofing-Jack [1: 295 -- 5 --> 300]
H4-painting-Jim [1: 93 -- 10 --> 103]
H4-windows-Joe [1: 305 -- 5 --> 310]
H4-facade-Jack [1: 300 -- 10 --> 310]
H4-garden-Jim [1: 300 -- 5 --> 305]
H4-moving-Jim [1: 310 -- 5 --> 315]

The complete program can be viewed online in the <Install_dir>/cpoptimizer/examples/src/cpp/sched_optional.cpp file.