/// <summary>
/// Compares two solutions.
/// </summary>
/// <param name="s1">The first <code>Solution</code></param>
/// <param name="s2">The second <code>Solution</code></param>
/// <returns>-1, or 0, or 1 if solution1 dominates solution2, both are non-dominated, or solution1 is dominated by solution22, respectively.</returns>
public int Compare(Solution s1, Solution s2)
{
if (s1 == null)
{
return(1);
}
else if (s2 == null)
{
return(-1);
}
int dominate1; // dominate1 indicates if some objective of solution1
// dominates the same objective in solution2. dominate2
int dominate2; // is the complementary of dominate1.
dominate1 = 0;
dominate2 = 0;
int flag; //stores the result of the comparison
// Test to determine whether at least a solution violates some constraint
if (violationConstraintComparator.NeedToCompare(s1, s2))
{
return(violationConstraintComparator.Compare(s1, s2));
}
// Equal number of violated constraints. Applying a dominance Test then
double value1, value2;
for (int i = 0; i < s1.NumberOfObjectives; i++)
{
value1 = s1.Objective[i];
value2 = s2.Objective[i];
if (value1 < value2)
{
flag = -1;
}
else if (value1 > value2)
{
flag = 1;
}
else
{
flag = 0;
}
if (flag == -1)
{
dominate1 = 1;
}
if (flag == 1)
{
dominate2 = 1;
}
}
if (dominate1 == dominate2)
{
return(0); //No one dominate the other
}
if (dominate1 == 1)
{
return(-1); // solution1 dominate
}
return(1); // solution2 dominate
}
/// <summary>
///
/// </summary>
/// <param name="indiv">Child solution</param>
/// <param name="id">The id of current subproblem</param>
/// <param name="type">Update solutions in - neighborhood (1) or whole population (otherwise)</param>
private void UpdateProblem(Solution indiv, int id, int type)
{
int size;
int time;
time = 0;
if (type == 1)
{
size = neighborhood[id].Length;
}
else
{
size = population.Size();
}
int[] perm = new int[size];
Utils.RandomPermutation(perm, size);
for (int i = 0; i < size; i++)
{
int k;
if (type == 1)
{
k = neighborhood[id][perm[i]];
}
else
{
k = perm[i]; // calculate the values of objective function regarding the current subproblem
}
double f1, f2;
f1 = FitnessFunction(population.Get(k), lambda[k]);
f2 = FitnessFunction(indiv, lambda[k]);
/**
* *** This part is new according to the violation of constraints ****
*/
if (comparator.NeedToCompare(population.Get(k), indiv))
{
int flag = comparator.Compare(population.Get(k), indiv);
if (flag == 1)
{
population.Replace(k, new Solution(indiv));
}
else if (flag == 0)
{
if (f2 < f1)
{
population.Replace(k, new Solution(indiv));
time++;
}
}
}
else
{
if (f2 < f1)
{
population.Replace(k, new Solution(indiv));
time++;
}
}
// the maximal number of solutions updated is not allowed to exceed 'limit'
if (time >= nr)
{
return;
}
}
}