public HCluster(int id, HCluster left, HCluster right )
{
Id = id;
Left = left;
Right = right;
Points = left.Points.Concat(right.Points);
}
public HCluster(int id, HCluster left, HCluster right)
{
Id = id;
Left = left;
Right = right;
Points = left.Points.Concat(right.Points);
}
public HCluster Generate(IEnumerable <T> examples, ILinker linker)
{
// Initialize
Linker = linker;
var clusters = new List <HCluster>();
var distances = new Dictionary <Tuple <int, int>, double>();
// Load data
if (Description == null)
{
Description = Converter.GetDescription(typeof(T)).BuildDictionaries <T>(examples);
}
Matrix X = Converter.Convert <T>(examples, Description.Features);
// Create a new cluster for each data point
for (int i = 0; i < X.Rows; i++)
{
clusters.Add(new HCluster {
Id = i, Points = new Vector[] { X[i, VectorType.Row] }
});
}
// Set the current closest distance/pair to the first pair of clusters
var key = new Tuple <int, int>(0, 0);
var distance = 0.0;
var clusterId = -1;
while (clusters.Count > 1)
{
var closestClusters = new Tuple <int, int>(0, 1);
var smallestDistance = Linker.Distance(clusters[0].Points, clusters[1].Points);
// Loop through each of the clusters looking for the two closest
for (int i = 0; i < clusters.Count; i++)
{
for (int j = i + 1; j < clusters.Count; j++)
{
key = new Tuple <int, int>(clusters[i].Id, clusters[j].Id);
// Cache the distance if it hasn't been calculated yet
if (!distances.ContainsKey(key))
{
distances.Add(key, Linker.Distance(clusters[i].Points, clusters[j].Points));
}
// Update closest clusters and distance if necessary
distance = distances[key];
if (distance < smallestDistance)
{
smallestDistance = distance;
closestClusters = new Tuple <int, int>(i, j);
}
}
}
var min = System.Math.Min(closestClusters.Item1, closestClusters.Item2);
var max = System.Math.Max(closestClusters.Item1, closestClusters.Item2);
var newCluster = new HCluster(clusterId, clusters[min],
clusters[max]);
// Remove the merged clusters
clusters.RemoveAt(min);
clusters.RemoveAt(max - 1);
// Add new cluster
clusters.Add(newCluster);
clusterId += 1;
}
return(clusters.Single());
}
