public Tuple <ISet <T>, ISet <T> > Partition(Tuple <T, T> promoted, ICollection <T> dataSet, DistanceMetric <T> distanceMetric)
{
List <T> queue1 = new List <T>(dataSet);
queue1.Sort((data1, data2) =>
{
Double distance1 = distanceMetric.Invoke(data1, promoted.Item1);
Double distance2 = distanceMetric.Invoke(data2, promoted.Item1);
return(distance1.CompareTo(distance2));
});
List <T> queue2 = new List <T>(dataSet);
queue2.Sort((data1, data2) =>
{
Double distance1 = distanceMetric.Invoke(data1, promoted.Item2);
Double distance2 = distanceMetric.Invoke(data2, promoted.Item2);
return(distance1.CompareTo(distance2));
});
ISet <T> first = new HashSet <T>();
ISet <T> second = new HashSet <T>();
int index1 = 0;
int index2 = 0;
while (index1 < queue1.Count || index2 != queue2.Count)
{
while (index1 < queue1.Count)
{
T data = queue1[index1++];
if (!second.Contains(data))
{
first.Add(data);
break;
}
}
while (index2 < queue2.Count)
{
T data = queue2[index2++];
if (!first.Contains(data))
{
second.Add(data);
break;
}
}
}
return(new Tuple <ISet <T>, ISet <T> >(first, second));
}
public Tuple <ISet <T>, ISet <T> > Partition(Tuple <T, T> promoted, ICollection <T> dataSet, DistanceMetric <T> distanceMetric)
{
ISet <T> first = new HashSet <T>();
ISet <T> second = new HashSet <T>();
foreach (T data in dataSet)
{
if (distanceMetric.Invoke(data, promoted.Item1) <= distanceMetric.Invoke(data, promoted.Item2))
{
first.Add(data);
}
else
{
second.Add(data);
}
}
return(new Tuple <ISet <T>, ISet <T> >(first, second));
}
/// <summary>
/// Chooses the two items from the <c>dataSet</c> which are the farthest from each other.
/// </summary>
/// <param name="dataSet">The data set.</param>
/// <param name="distanceMetric">The distance metric.</param>
/// <returns>
/// a pair of promoted items
/// </returns>
public Tuple <T, T> Promote(ICollection <T> dataSet, DistanceMetric <T> distanceMetric)
{
T[] data = new T[dataSet.Count];
dataSet.CopyTo(data, 0);
T first = data[0];
T second = data[1];
Double maxDistance = distanceMetric.Invoke(first, second);
for (int i = 0; i < data.Length; i++)
{
for (int j = i + 1; j < data.Length; j++)
{
Double distance = distanceMetric.Invoke(data[i], data[j]);
if (distance > maxDistance)
{
maxDistance = distance;
first = data[i];
second = data[j];
}
}
}
return(new Tuple <T, T>(first, second));
}