public void updateMedoids(int K, Cluster[] clusters)
{
for (int clusterIdx = 0; clusterIdx < K; clusterIdx++)
{
clusters[clusterIdx].updateMedoid();
}
}
public void selectInitialMedoids(Matrix<double> distanceMX, int K,
out Cluster[] clusters, out double totalCost)
{
Dictionary<double, int> dictOfMiddleness = computeMiddlenessOfObjs(distanceMX);
int[] selectedMedoids = determineMedoidsBasedOnMiddleness(dictOfMiddleness, K);
clusters = buildClusters(distanceMX, K, selectedMedoids);
totalCost = utils.calculateTotalCost(K, clusters);
}
public double calculateTotalCost(int K, Cluster[] clusters)
{
double totalCost = 0.0;
for (int clusterIdx = 0; clusterIdx < K; clusterIdx++)
{
totalCost += clusters[clusterIdx].calculateCost();
}
return totalCost;
}
private Cluster[] buildClusters(Matrix<double> distanceMX, int K, int[] selectedMedoids)
{
Cluster[] clusters = new Cluster[K];
for (int selectedMedoidIdx = 0; selectedMedoidIdx < K; selectedMedoidIdx++)
{
clusters[selectedMedoidIdx] = new Cluster(distanceMX, selectedMedoids[selectedMedoidIdx]);
}
utils.assign(distanceMX, K, selectedMedoids, clusters);
return clusters;
}
public double assignObjsToClusters(Matrix<double> distanceMX, int K, Cluster[] clusters)
{
int[] selectedMedoids = new int[K];
for (int selectedMedoidIdx = 0; selectedMedoidIdx < K; selectedMedoidIdx++)
{
selectedMedoids[selectedMedoidIdx] = clusters[selectedMedoidIdx].MedoidIdx;
clusters[selectedMedoidIdx].Members.Clear();
}
utils.assign(distanceMX, K, selectedMedoids, clusters);
double totalCost = utils.calculateTotalCost(K, clusters);
return totalCost;
}
public void assign(Matrix<double> distanceMX, int K, int[] selectedMedoids, Cluster[] clusters)
{
int nObj = distanceMX.RowCount;
for (int idx = 0; idx < nObj; idx++)
{
double minMedoidDist = double.MaxValue;
int minSelectedMedoidIdx = -1;
for (int selectedMedoidIdx = 0; selectedMedoidIdx < K; selectedMedoidIdx++)
{
double currentMedoidDist = distanceMX[idx, selectedMedoids[selectedMedoidIdx]];
if (currentMedoidDist < minMedoidDist)
{
minMedoidDist = currentMedoidDist;
minSelectedMedoidIdx = selectedMedoidIdx;
}
}
clusters[minSelectedMedoidIdx].Members.Add(idx);
}
}
