private double getCompleteLinkDistance(HierarchicalCluster c1, HierarchicalCluster c2) {
// merge clusters with the "smallest" "maximum pairwise distance"
// return maximum pairwise distance
HashSet<Item> itemsC1 = c1.getItems();
HashSet<Item> itemsC2 = c2.getItems();
double maxDist = 0.0;
for (Item item1 : itemsC1) {
for (Item item2 : itemsC2) {
double distance = item1.getDistance(item2);
if (distance > maxDist) {
maxDist = distance;
}
}
}
return maxDist;
}
private double getSingleLinkDistance(HierarchicalCluster c1, HierarchicalCluster c2) {
// merge the two clusters with the smallest minimum pairwise distance
// return minimum pairwise distance
HashSet<Item> itemsC1 = c1.getItems();
HashSet<Item> itemsC2 = c2.getItems();
double minDist = Double.MAX_VALUE;
for (Item item1 : itemsC1) {
for (Item item2 : itemsC2) {
double distance = item1.getDistance(item2);
if (distance < minDist) {
minDist = distance;
}
}
}
return minDist;
}
private double getAvgLinkDistance(HierarchicalCluster c1, HierarchicalCluster c2) {
// merge the two clusters with the smallest average distance between any
// two points in the clusters
// return average distance between each two point in two clusters.
HashSet<Item> itemsC1 = c1.getItems();
HashSet<Item> itemsC2 = c2.getItems();
double sumDist = 0.0;
int n = 0;
for (Item item1 : itemsC1) {
for (Item item2 : itemsC2) {
sumDist += item1.getDistance(item2);
n++;
}
}
double avgDist = sumDist / n;
return avgDist;
}