EM最大期望算法的模糊聚类的实现

EM最大期望算法的模糊聚类的实现

Author: linyiqun

DataMining_EM/Client.java

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+package DataMining_EM;
+
+/**
+ * EM期望最大化算法场景调用类
+ * @author lyq
+ *
+ */
+public class Client {
+	public static void main(String[] args){
+		String filePath = "C:\\Users\\lyq\\Desktop\\icon\\input.txt";
+		
+		EMTool tool = new EMTool(filePath);
+		tool.readDataFile();
+		tool.exceptMaxStep();
+	}
+}

DataMining_EM/EMTool.java

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+package DataMining_EM;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.text.MessageFormat;
+import java.util.ArrayList;
+
+/**
+ * EM最大期望算法工具类
+ * 
+ * @author lyq
+ * 
+ */
+public class EMTool {
+	// 测试数据文件地址
+	private String dataFilePath;
+	// 测试坐标点数据
+	private String[][] data;
+	// 测试坐标点数据列表
+	private ArrayList<Point> pointArray;
+	// 目标C1点
+	private Point p1;
+	// 目标C2点
+	private Point p2;
+
+	public EMTool(String dataFilePath) {
+		this.dataFilePath = dataFilePath;
+		pointArray = new ArrayList<>();
+	}
+
+	/**
+	 * 从文件中读取数据
+	 */
+	public void readDataFile() {
+		File file = new File(dataFilePath);
+		ArrayList<String[]> dataArray = new ArrayList<String[]>();
+
+		try {
+			BufferedReader in = new BufferedReader(new FileReader(file));
+			String str;
+			String[] tempArray;
+			while ((str = in.readLine()) != null) {
+				tempArray = str.split(" ");
+				dataArray.add(tempArray);
+			}
+			in.close();
+		} catch (IOException e) {
+			e.getStackTrace();
+		}
+
+		data = new String[dataArray.size()][];
+		dataArray.toArray(data);
+
+		// 开始时默认取头2个点作为2个簇中心
+		p1 = new Point(Integer.parseInt(data[0][0]),
+				Integer.parseInt(data[0][1]));
+		p2 = new Point(Integer.parseInt(data[1][0]),
+				Integer.parseInt(data[1][1]));
+
+		Point p;
+		for (String[] array : data) {
+			// 将数据转换为对象加入列表方便计算
+			p = new Point(Integer.parseInt(array[0]),
+					Integer.parseInt(array[1]));
+			pointArray.add(p);
+		}
+	}
+
+	/**
+	 * 计算坐标点对于2个簇中心点的隶属度
+	 * 
+	 * @param p
+	 *            待测试坐标点
+	 */
+	private void computeMemberShip(Point p) {
+		// p点距离第一个簇中心点的距离
+		double distance1 = 0;
+		// p距离第二个中心点的距离
+		double distance2 = 0;
+
+		// 用欧式距离计算
+		distance1 = Math.pow(p.getX() - p1.getX(), 2)
+				+ Math.pow(p.getY() - p1.getY(), 2);
+		distance2 = Math.pow(p.getX() - p2.getX(), 2)
+				+ Math.pow(p.getY() - p2.getY(), 2);
+
+		// 计算对于p1点的隶属度，与距离成反比关系，距离靠近越小，隶属度越大，所以要用大的distance2另外的距离来表示
+		p.setMemberShip1(distance2 / (distance1 + distance2));
+		// 计算对于p2点的隶属度
+		p.setMemberShip2(distance1 / (distance1 + distance2));
+	}
+
+	/**
+	 * 执行期望最大化步骤
+	 */
+	public void exceptMaxStep() {
+		// 新的优化过的簇中心点
+		double p1X = 0;
+		double p1Y = 0;
+		double p2X = 0;
+		double p2Y = 0;
+		double temp1 = 0;
+		double temp2 = 0;
+		// 误差值
+		double errorValue1 = 0;
+		double errorValue2 = 0;
+		// 上次更新的簇点坐标
+		Point lastP1 = null;
+		Point lastP2 = null;
+
+		// 当开始计算的时候，或是中心点的误差值超过1的时候都需要再次迭代计算
+		while (lastP1 == null || errorValue1 > 1.0 || errorValue2 > 1.0) {
+			for (Point p : pointArray) {
+				computeMemberShip(p);
+				p1X += p.getMemberShip1() * p.getMemberShip1() * p.getX();
+				p1Y += p.getMemberShip1() * p.getMemberShip1() * p.getY();
+				temp1 += p.getMemberShip1() * p.getMemberShip1();
+
+				p2X += p.getMemberShip2() * p.getMemberShip2() * p.getX();
+				p2Y += p.getMemberShip2() * p.getMemberShip2() * p.getY();
+				temp2 += p.getMemberShip2() * p.getMemberShip2();
+			}
+
+			lastP1 = new Point(p1.getX(), p1.getY());
+			lastP2 = new Point(p2.getX(), p2.getY());
+
+			// 套公式计算新的簇中心点坐标,最最大化处理
+			p1.setX(p1X / temp1);
+			p1.setY(p1Y / temp1);
+			p2.setX(p2X / temp2);
+			p2.setY(p2Y / temp2);
+
+			errorValue1 = Math.abs(lastP1.getX() - p1.getX())
+					+ Math.abs(lastP1.getY() - p1.getY());
+			errorValue2 = Math.abs(lastP2.getX() - p2.getX())
+					+ Math.abs(lastP2.getY() - p2.getY());
+		}
+
+		System.out.println(MessageFormat.format(
+				"簇中心节点p1({0}, {1}), p2({2}, {3})", p1.getX(), p1.getY(),
+				p2.getX(), p2.getY()));
+	}
+
+}

DataMining_EM/Point.java

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+package DataMining_EM;
+
+/**
+ * 坐标点类
+ * 
+ * @author lyq
+ * 
+ */
+public class Point {
+	// 坐标点横坐标
+	private double x;
+	// 坐标点纵坐标
+	private double y;
+	// 坐标点对于P1的隶属度
+	private double memberShip1;
+	// 坐标点对于P2的隶属度
+	private double memberShip2;
+
+	public Point(double d, double e) {
+		this.x = d;
+		this.y = e;
+	}
+
+	public double getX() {
+		return x;
+	}
+
+	public void setX(double x) {
+		this.x = x;
+	}
+
+	public double getY() {
+		return y;
+	}
+
+	public void setY(double y) {
+		this.y = y;
+	}
+
+	public double getMemberShip1() {
+		return memberShip1;
+	}
+
+	public void setMemberShip1(double memberShip1) {
+		this.memberShip1 = memberShip1;
+	}
+
+	public double getMemberShip2() {
+		return memberShip2;
+	}
+
+	public void setMemberShip2(double memberShip2) {
+		this.memberShip2 = memberShip2;
+	}
+
+}