/**
* Find the two clusters with the shortest Wishart distance among all clusters in the given
* cluster list.
*
* @param clusterCenterList The cluster list.
* @param clusterPair The indices of the two clusters with the shortest Wishart distance.
* @return The shortest Wishart distance.
*/
private double computeShortestDistance(
final java.util.List<ClusterInfo> clusterCenterList, final int[] clusterPair) {
final int numClusters = clusterCenterList.size();
double shortestDistance = Double.MAX_VALUE;
if (numClusters <= 3) {
return shortestDistance;
}
double d;
for (int i = 0; i < numClusters - 1; i++) {
if (clusterCenterList.get(i).size >= maxClusterSize) {
continue;
}
for (int j = i + 1; j < numClusters; j++) {
if (clusterCenterList.get(j).size >= maxClusterSize) {
continue;
}
d =
HAlphaWishart.computeWishartDistance(
clusterCenterList.get(i).centerRe,
clusterCenterList.get(i).centerIm,
clusterCenterList.get(j));
if (d < shortestDistance) {
shortestDistance = d;
clusterPair[0] = i;
clusterPair[1] = j;
}
}
}
return shortestDistance;
}
/**
* Find the nearest cluster for a given T3 matrix using Wishart distance
*
* @param Tr Real part of the T3 matrix
* @param Ti Imaginary part of the T3 matrix
* @param clusterCenters The cluster centers
* @return The zone index for the nearest cluster
*/
public static int findClosestCluster(
final double[][] Tr, final double[][] Ti, final java.util.List<ClusterInfo> clusterCenters) {
double minDistance = Double.MAX_VALUE;
int clusterIndex = -1;
for (int c = 0; c < clusterCenters.size(); ++c) {
final double d = HAlphaWishart.computeWishartDistance(Tr, Ti, clusterCenters.get(c));
if (minDistance > d) {
minDistance = d;
clusterIndex = c;
}
}
return clusterIndex;
}