@Override
public void cluster(ArrayList<? extends DataPoint> dataPoints) {
{
// Initalize the clusters.
for (DataPoint dp : dataPoints) {
dp.setClusterId(-1);
}
}
{
// Main process
ArrayList<DataPoint> plane = new ArrayList(dataPoints.size());
ArrayList<DataPoint> neighbors = new ArrayList(16);
ArrayList<Integer> nearbyClusters = new ArrayList(4);
float e2 = epsilon * epsilon;
double d;
int lastClusterUsed = 0;
int id;
main:
for (DataPoint dp : dataPoints) {
// Check for neighbors.
neighbors.clear();
for (DataPoint other : plane) {
d = distance(dp, other);
if (d <= e2) {
neighbors.add(other);
}
}
if (neighbors.isEmpty()) {
// New Cluster
dp.setClusterId(lastClusterUsed++);
} else {
// Add to cluster.
nearbyClusters.clear();
for (DataPoint n : neighbors) {
nearbyClusters.add(n.getClusterId());
}
if (nearbyClusters.size() == 1) {
// Only near 1 cluster.
dp.setClusterId(nearbyClusters.get(0));
} else {
// Combine multiple clusters.
id = nearbyClusters.remove(0);
dp.setClusterId(id);
for (DataPoint other : plane) {
if (nearbyClusters.contains(other.getClusterId())) {
other.setClusterId(id);
}
}
}
}
plane.add(dp);
}
}
{
// Condense the cluster ids.
ArrayList<Integer> clusterIdsUsed = new ArrayList(16);
int id;
for (DataPoint dp : dataPoints) {
id = dp.getClusterId();
if (!clusterIdsUsed.contains(id)) {
clusterIdsUsed.add(id);
}
}
for (DataPoint dp : dataPoints) {
dp.setClusterId(clusterIdsUsed.indexOf(dp.getClusterId()));
}
}
}
