我正在计算java中某些点的几何中位数。(x,y)要计算Geometric median，首先我要计算centroid所有点，然后centroid用它来计算Geometric median。我的代码工作正常，但有时它会进入无限循环（我认为。）。问题在于我的while情况。这个while条件应该根据输入点改变，但我不知道怎么做。下面我放完整的代码。
import java.util.ArrayList;
public class GeometricMedian {
private static ArrayList<Point> points = new ArrayList<Point>();
private class Point {
private double x;
private double y;
Point(double a, double b) {
x = a;
y = b;
}
}
public static void main(String[] args) {
GeometricMedian gm = new GeometricMedian();
gm.addPoints();
Point centroid = gm.getCentroid();
Point geoMedian = gm.getGeoMedian(centroid);
System.out.println("GeometricMedian= {" + (float) geoMedian.x + ", "
+ (float) geoMedian.y + "}");
}
public void addPoints() {
points.add(new Point(0, 1));
points.add(new Point(2, 5));
points.add(new Point(3, 1));
points.add(new Point(4, 0));
}
public Point getCentroid() {
double cx = 0.0D;
double cy = 0.0D;
for (int i = 0; i < points.size(); i++) {
Point pt = points.get(i);
cx += pt.x;
cy += pt.y;
}
return new Point(cx / points.size(), cy / points.size());
}
public Point getGeoMedian(Point start) {
double cx = 0;
double cy = 0;
double centroidx = start.x;
double centroidy = start.y;
do {
double totalWeight = 0;
for (int i = 0; i < points.size(); i++) {
Point pt = points.get(i);
double weight = 1 / distance(pt.x, pt.y, centroidx, centroidy);
cx += pt.x * weight;
cy += pt.y * weight;
totalWeight += weight;
}
cx /= totalWeight;
cy /= totalWeight;
} while (Math.abs(cx - centroidx) > 0.5
|| Math.abs(cy - centroidy) > 0.5);// Probably this condition
// needs to change
return new Point(cx, cy);
}
private static double distance(double x1, double y1, double x2, double y2) {
x1 -= x2;
y1 -= y2;
return Math.sqrt(x1 * x1 + y1 * y1);
}
}
请帮我修复这个错误，如果有更好的方法来计算Geometric median一些 2D 点，请写在这里。谢谢你。