// returns the array of memberships to each cluster from inputted point
private double[] findMemArr(DataPoint point) {
double[] memberships = new double[clusters.size()];
for (int j = 0; j < clusters.size(); j++) {
double sum = 0;
double distA = point.distTo(clusters.get(j).getCentroid());
if (distA != 0.0) {
for (Cluster c : clusters) {
c.setCentroid();
double distB = point.distTo(c.getCentroid());
if (distB == 0.0) {
sum = Double.POSITIVE_INFINITY;
break;
}
sum += pow(distA / distB, 2.0 / (m - 1.0));
}
}
double membership;
if (sum == 0.0) {
membership = 1.0;
} else if (sum == Double.POSITIVE_INFINITY) {
membership = 0.0;
} else {
membership = 1.0 / sum;
}
memberships[j] = membership;
}
return memberships;
}
// sets the membership map of each point in the clusters
private void findMembership() {
double[] memberships;
for (Cluster clust : clusters) {
clust.setCentroid();
for (DataPoint pt : clust.getData()) {
memberships = findMemArr(pt);
for (int i = 0; i < memberships.length; i++) {
pt.setMembership(i, memberships[i]);
}
}
}
}