IloInt choose(IloCP cp, IloIntVarArray vars) {
IloNum best = IloInfinity;
IloInt bestIndex = -1;
IloInt n = vars.getSize();
for (IloInt i = 0; i < n; i++) {
if (!cp.isFixed(vars[i])) {
IloNum c = CalcCentroid(cp, vars[i]);
if (c < best) {
best = c;
bestIndex = i;
}
}
}
return bestIndex;
}
void wqueens(IloEnv& env, IloModel& model, IloIntVarArray& vars)
{
cout << "Add 3 hard AllDiff constraints for the Queens problem." << endl;
model.add(vars); // ensure vars are the main decision variables
int nqueen = vars.getSize();
IloIntVarArray vars1(env, nqueen, -2 * nqueen, 2 * nqueen);
IloIntVarArray vars2(env, nqueen, -2 * nqueen, 2 * nqueen);
for (IloInt i = 0; i < nqueen; i++) {
model.add(vars1[i] == vars[i] + i);
model.add(vars2[i] == vars[i] - i);
}
model.add(IloAllDiff(env, vars));
model.add(IloAllDiff(env, vars1));
model.add(IloAllDiff(env, vars2));
}
void quasi(IloEnv& env, IloModel& model, IloIntVarArray& vars)
{
int n = sqrt((double)vars.getSize());
cout << "Add " << n * 2 << " hard AllDiff constraints for the \"homogeneous\" QuasiGroup problem." << endl;
for (int i = 0; i < n; i++) {
int pos = i * n;
IloIntVarArray vars1(env, n);
for (int j = 0; j < n; j++) {
vars1[j] = vars[pos];
pos++;
}
model.add(IloAllDiff(env, vars1));
}
for (int j = 0; j < n; j++) {
int pos = j;
IloIntVarArray vars1(env, n);
for (int i = 0; i < n; i++) {
vars1[i] = vars[pos];
pos += n;
}
model.add(IloAllDiff(env, vars1));
}
}
