The map coloring example can also be greatly simplified by the use of IloSingleMove and IloImprove. The local search part of the code can now be written as follows:

    IloNHood nhood = IloFlip(env, AllVars);
    IloGoal move = IloSingleMove(env, soln, nhood, IloImprove(env));
    while (solver.solve(move)) {
      solver.out() << "Move made:    Objective value = "
                   << soln.getObjectiveValue() << endl;
    }

For reference, the entire example using IloSingleMove is given below:

#include <ilsolver/iimls.h>
 
ILOSTLBEGIN
 
typedef enum { COLOR_DIRECT, COLOR_DELTAS,
               COLOR_NHOOD, COLOR_SINGLEMOVE } ColorType;
 
const char* Names[] = {"blue", "white"}; 
 
void print(IloSolver solver, const char* name, IloIntVar var) { 
  solver.out() << name << Names[(IloInt)solver.getValue(var)] << endl;
}
 
int main() {
  IloEnv env;
  try {
    IloModel model(env);
    
    IloIntVar Belgium(env, 0, 1), Denmark(env, 0, 1), 
              France(env, 0, 1), Germany(env, 0, 1), 
              Netherlands(env, 0, 1), Luxembourg(env, 0, 1);
    IloIntVarArray AllVars(env);
    AllVars.add(Belgium);
    AllVars.add(Denmark);
    AllVars.add(France);
    AllVars.add(Germany);
    AllVars.add(Netherlands);
    AllVars.add(Luxembourg);
    model.add(AllVars);
    model.add(France != Belgium); 
    model.add(France != Germany); 
    model.add(Belgium != Netherlands); 
    model.add(Germany != Netherlands); 
    model.add(Germany != Denmark); 
    IloIntVar quality(env, 0, 20000);
    model.add(quality == 257 * (France != Luxembourg)
                      + 9043 * (Luxembourg != Germany)
                      +  568 * (Luxembourg != Belgium));
    IloObjective obj = IloMaximize(env, quality);
    IloSolver solver(model);
    IloGoal generate = IloGenerate(env, AllVars);
    if (!solver.solve(generate)) {
      throw "Could not find an initial solution";
    }
    IloSolution soln(env, "Colors");
    soln.add(AllVars);
    soln.add(obj);
    soln.store(solver);
    solver.out() << "1st solution: Objective value = "
                 << soln.getObjectiveValue() << endl;
    IloNHood nhood = IloFlip(env, AllVars);
    IloGoal move = IloSingleMove(env, soln, nhood, IloImprove(env));
    while (solver.solve(move)) {
      solver.out() << "Move made:    Objective value = "
                   << soln.getObjectiveValue() << endl;
    }
    solver.solve(IloRestoreSolution(env, soln));
    print(solver, "Belgium:     ", Belgium); 
    print(solver, "Denmark:     ", Denmark); 
    print(solver, "France:      ", France); 
    print(solver, "Germany:     ", Germany); 
    print(solver, "Netherlands: ", Netherlands); 
    print(solver, "Luxembourg:  ", Luxembourg); 
  }
  catch(IloException &ex) {
    cout << "Caught : " << ex << endl;
  }
  catch(const char *ex) {
    cout << "Caught : " << ex << endl;
  }
  env.end();
  return 0;
}