protected override ItemArray <IItem> Relink(ItemArray <IItem> parents, PercentValue n)
 {
     if (parents.Length < 2)
     {
         throw new ArgumentException("The number of parents is smaller than 2.");
     }
     return(Apply(parents[0], parents.Skip(1).ToArray(), DistanceMatrix, n));
 }
 protected override ItemArray<IItem> Relink(ItemArray<IItem> parents, PercentValue n) {
   if (parents.Length < 2)
     throw new ArgumentException("The number of parents is smaller than 2.");
   return Apply(parents[0], parents.Skip(1).ToArray(), DistanceMatrix, n);
 }