algorithms-for-computing-li.../LinearRegressionTool/src/main/java/presenter/algorithms/naiv/NaivLeastMedianOfSquaresEst...

95 lines
2.6 KiB
Java

package presenter.algorithms.naiv;
import model.Line;
import model.Point;
import presenter.algorithms.Algorithm;
import presenter.algorithms.util.FastElementSelector;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
/**
* Implementierung verschiedener Algorithmen zur Berechnung von Ausgleichsgeraden.
*
* @Author: Armin Wolf
* @Email: a_wolf28@uni-muenster.de
* @Date: 15.09.2017.
*/
public class NaivLeastMedianOfSquaresEstimator implements Algorithm {
private ArrayList<Point> set = new ArrayList<>();
private Integer n;
private Double ds, b, m;
public NaivLeastMedianOfSquaresEstimator(LinkedList<Line> lines) {
for (Line l : lines) {
set.add(new Point(l.getM(), l.getB()));
}
}
private void crudeAlg() {
ds = Double.MAX_VALUE;
b = 0d;
m = 0d;
ArrayList<Point> triple = new ArrayList<>();
Double beta;
Double alpha;
Double dijk;
System.out.println("=== S T A R T - naiv L M S ===");
long start;
long end;
start = System.currentTimeMillis();
for (Point i : set) {
for (Point j : set) {
for (Point k : set) {
triple.add(i);
triple.add(j);
triple.add(k);
Collections.sort(triple);
beta = (triple.get(0).getY() - triple.get(2).getY()) / (triple.get(0).getX() - triple.get(2).getX());
alpha = (triple.get(1).getY() + triple.get(2).getY() - (beta * (triple.get(1).getX() + triple.get(2).getX()))) / 2f;
dijk = f(alpha, beta);
if (dijk < ds) {
ds = dijk;
b = alpha;
m = beta;
// System.out.printf("Distanz: %6.2f\tAlpha: %6.2f\tBeta: %6.2f",ds,b,m);
}
triple.clear();
}
}
}
end = System.currentTimeMillis();
System.out.println("Zeit: "+ ((end-start)/1000));
}
private Double f(Double a, Double b) {
ArrayList<Double> res = new ArrayList<>();
for (Point p : set) {
res.add(Math.abs(p.getY() - (a + b * p.getX())));
}
return FastElementSelector.randomizedSelect(res, res.size() / 2);
}
@Override
public void run() {
crudeAlg();
}
@Override
public void getResult() {
}
public Double getB() {
return b * -1;
}
public Double getM() {
return m * -1;
}
}