hill climbing java

Main.java

import java.lang.Math;
import java.util.ArrayList;

class Point {
    public double x;
    public double y;
    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }
}

class PointHill {
    public ArrayList<Point> points;

    private double pow2(double x) {
        return x*x;
    }

    private double dx_distance(double x1,double y1,double x2,double y2) {
        return (x1-x2)/Math.sqrt(pow2(x1-x2) + pow2(y1-y2));
    }

    private double dy_distance(double x1, double y1, double x2, double y2) {
        return (y1-y2)/Math.sqrt(pow2(x1-x2) + pow2(y1-y2));
    }

    private Point dxdy_distance(double x1,double y1,double x2,double y2) {
        Point d = new Point(this.dx_distance(x1,y1,x2,y2), this.dy_distance(x1,y1,x2,y2));
        return d;
    }

    private double distance(double x1,double y1,double x2,double y2) {
        return Math.sqrt(pow2((x1-x2)) + pow2((y1-y2)));
    }

    private Point calc_deriv_score(Point point) {
        Point[] points = this.points.toArray(new Point[this.points.size()]);
        double x = point.x;
        double y = point.y;
        double dx = 0;
        double dy = 0;
        double xa,ya;
        Point di;
        for(int i=0; i<points.length; i++) {
            xa = points[i].x;
            ya = points[i].y;
            di = dxdy_distance(x,y,xa,ya);
            dx += di.x;
            dy += di.y;
        }
        return new Point(dx, dy);
    }

    public Point get_result() {
        Point start = new Point(0,0);
        int eps = 100;
        double lr = 0.1;
        Point d;
        for(int i=0;i < eps; i++) {
            d = this.calc_deriv_score(start);
            start.x -= d.x * lr;
            start.y -= d.y * lr;
        }
        return start;
    }

    public PointHill() {
        this.points = new ArrayList<Point>();
    }

    public void addPoint(double x, double y) {
        this.points.add(new Point(x,y));
    }

}

public class Main {

    public static void main(String[] args) {
        Point result;
        PointHill hill = new PointHill();
        hill.addPoint(2,2); // tambah titik koordinat 2,2
        hill.addPoint(3,4); // tambah titik koordinat 3,4
        hill.addPoint(4,2); // tambah titik koordinat 4,2
        hill.addPoint(5,4); // tambah titik koordinat 5,4
        result = hill.get_result(); // hitung titik optimum
        System.out.println("X = "+result.x+"; Y = "+result.y);
    }

}