/**
* Creates a ClusteringFeature.
*
* @param center the center point
* @param radius the radius
*/
public ClusteringFeature(double[] center, double radius) {
super(center, radius, 1);
this.numPoints = 1;
this.sumPoints = new double[center.length];
System.arraycopy(center, 0, this.sumPoints, 0, center.length);
this.sumSquaredLength = Metric.distanceSquared(center);
}
/**
* Calculates the k-means costs of the ClusteringFeature and a point too a center.
*
* @param center the center too calculate the costs
* @param point the point too calculate the costs
* @return the costs
*/
public double calcKMeansCosts(double[] center, double[] point) {
assert (this.sumPoints.length == center.length && this.sumPoints.length == point.length);
return (this.sumSquaredLength + Metric.distanceSquared(point))
- 2 * Metric.dotProductWithAddition(this.sumPoints, point, center)
+ (this.numPoints + 1) * Metric.dotProduct(center);
}
