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遗传算法经典java实现(遗传算法经典java实现方法)

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java实验 遗传算法

你好,我以前从csdn上下过一个源代码,不过没试过怎么用,给你参考一下:

import java.awt.BorderLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.JScrollPane;

import javax.swing.JTextArea;

import javax.swing.JTextField;

/**

* 编写者: 赖志环

* 标准遗传算法求解函数

* 编写日期: 2007-12-2

*/

class Best {

public int generations; //最佳适应值代号

public String str; //最佳染色体

public double fitness; //最佳适应值

}

public class SGAFrame extends JFrame {

private JTextArea textArea;

private String str = "";

private Best best = null; //最佳染色体

private String[] ipop = new String[10]; //染色体

private int gernation = 0; //染色体代号

public static final int GENE = 22; //基因数

/**

* Launch the application

* @param args

*/

public static void main(String args[]) {

try {

SGAFrame frame = new SGAFrame();

frame.setVisible(true);

} catch (Exception e) {

e.printStackTrace();

}

}

/**

* Create the frame

*/

public SGAFrame() {

super();

this.ipop = inialPops();

getContentPane().setLayout(null);

setBounds(100, 100, 461, 277);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

final JLabel label = new JLabel();

label.setText("X的区间:");

label.setBounds(23, 10, 88, 15);

getContentPane().add(label);

final JLabel label_1 = new JLabel();

label_1.setText("[-255,255]");

label_1.setBounds(92, 10, 84, 15);

getContentPane().add(label_1);

final JButton button = new JButton();

button.addActionListener(new ActionListener() {

public void actionPerformed(final ActionEvent e) {

SGAFrame s = new SGAFrame();

str = str + s.process() + "\n";

textArea.setText(str);

}

});

button.setText("求最小值");

button.setBounds(323, 27, 99, 23);

getContentPane().add(button);

final JLabel label_2 = new JLabel();

label_2.setText("利用标准遗传算法求解函数f(x)=(x-5)*(x-5)的最小值:");

label_2.setBounds(23, 31, 318, 15);

getContentPane().add(label_2);

final JPanel panel = new JPanel();

panel.setLayout(new BorderLayout());

panel.setBounds(23, 65, 399, 164);

getContentPane().add(panel);

final JScrollPane scrollPane = new JScrollPane();

panel.add(scrollPane, BorderLayout.CENTER);

textArea = new JTextArea();

scrollPane.setViewportView(textArea);

//

}

/**

* 初始化一条染色体(用二进制字符串表示)

* @return 一条染色体

*/

private String inialPop() {

String res = "";

for (int i = 0; i GENE; i++) {

if (Math.random() 0.5) {

res += "0";

} else {

res += "1";

}

}

return res;

}

/**

* 初始化一组染色体

* @return 染色体组

*/

private String[] inialPops() {

String[] ipop = new String[10];

for (int i = 0; i 10; i++) {

ipop[i] = inialPop();

}

return ipop;

}

/**

* 将染色体转换成x的值

* @param str 染色体

* @return 染色体的适应值

*/

private double calculatefitnessvalue(String str) {

int b = Integer.parseInt(str, 2);

//String str1 = "" + "/n";

double x = -255 + b * (255 - (-255)) / (Math.pow(2, GENE) - 1);

//System.out.println("X = " + x);

double fitness = -(x - 5) * (x - 5);

//System.out.println("f(x)=" + fitness);

//str1 = str1 + "X=" + x + "/n"

//+ "f(x)=" + "fitness" + "/n";

//textArea.setText(str1);

return fitness;

}

/**

* 计算群体上每个个体的适应度值;

* 按由个体适应度值所决定的某个规则选择将进入下一代的个体;

*/

private void select() {

double evals[] = new double[10]; // 所有染色体适应值

double p[] = new double[10]; // 各染色体选择概率

double q[] = new double[10]; // 累计概率

double F = 0; // 累计适应值总和

for (int i = 0; i 10; i++) {

evals[i] = calculatefitnessvalue(ipop[i]);

if (best == null) {

best = new Best();

best.fitness = evals[i];

best.generations = 0;

best.str = ipop[i];

} else {

if (evals[i] best.fitness) // 最好的记录下来

{

best.fitness = evals[i];

best.generations = gernation;

best.str = ipop[i];

}

}

F = F + evals[i]; // 所有染色体适应值总和

}

for (int i = 0; i 10; i++) {

p[i] = evals[i] / F;

if (i == 0)

q[i] = p[i];

else {

q[i] = q[i - 1] + p[i];

}

}

for (int i = 0; i 10; i++) {

double r = Math.random();

if (r = q[0]) {

ipop[i] = ipop[0];

} else {

for (int j = 1; j 10; j++) {

if (r q[j]) {

ipop[i] = ipop[j];

break;

}

}

}

}

}

/**

* 交叉操作

* 交叉率为25%,平均为25%的染色体进行交叉

*/

private void cross() {

String temp1, temp2;

for (int i = 0; i 10; i++) {

if (Math.random() 0.25) {

double r = Math.random();

int pos = (int) (Math.round(r * 1000)) % GENE;

if (pos == 0) {

pos = 1;

}

temp1 = ipop[i].substring(0, pos)

+ ipop[(i + 1) % 10].substring(pos);

temp2 = ipop[(i + 1) % 10].substring(0, pos)

+ ipop[i].substring(pos);

ipop[i] = temp1;

ipop[(i + 1) / 10] = temp2;

}

}

}

/**

* 基因突变操作

* 1%基因变异m*pop_size 共180个基因,为了使每个基因都有相同机会发生变异,

* 需要产生[1--180]上均匀分布的

*/

private void mutation() {

for (int i = 0; i 4; i++) {

int num = (int) (Math.random() * GENE * 10 + 1);

int chromosomeNum = (int) (num / GENE) + 1; // 染色体号

int mutationNum = num - (chromosomeNum - 1) * GENE; // 基因号

if (mutationNum == 0)

mutationNum = 1;

chromosomeNum = chromosomeNum - 1;

if (chromosomeNum = 10)

chromosomeNum = 9;

//System.out.println("变异前" + ipop[chromosomeNum]);

String temp;

if (ipop[chromosomeNum].charAt(mutationNum - 1) == '0') {

if (mutationNum == 1) {

temp = "1" + ipop[chromosomeNum].substring

(mutationNum);

} else {

if (mutationNum != GENE) {

temp = ipop[chromosomeNum].substring(0, mutationNum -

1) + "1" + ipop

[chromosomeNum].substring(mutationNum);

} else {

temp = ipop[chromosomeNum].substring(0, mutationNum -

1) + "1";

}

}

} else {

if (mutationNum == 1) {

temp = "0" + ipop[chromosomeNum].substring

(mutationNum);

} else {

if (mutationNum != GENE) {

temp = ipop[chromosomeNum].substring(0, mutationNum -

1) + "0" + ipop

[chromosomeNum].substring(mutationNum);

} else {

temp = ipop[chromosomeNum].substring(0, mutationNum -

1) + "1";

}

}

}

ipop[chromosomeNum] = temp;

//System.out.println("变异后" + ipop[chromosomeNum]);

}

}

/**

* 执行遗传算法

*/

public String process() {

String str = "";

for (int i = 0; i 10000; i++) {

this.select();

this.cross();

this.mutation();

gernation = i;

}

str = "最小值" + best.fitness + ",第" + best.generations + "个染色体";

return str;

}

}

求《Java遗传算法编程》全文免费下载百度网盘资源,谢谢~

《Java遗传算法编程》百度网盘pdf最新全集下载:

链接:

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简介:本书简单、直接地介绍了遗传算法,并且针对所讨论的示例问题,给出了Java代码的算法实现。全书分为6章。第1章简单介绍了人工智能和生物进化的知识背景,这也是遗传算法的历史知识背景。第2章给出了一个基本遗传算法的实现;第4章和第5章,分别针对机器人控制器、旅行商问题、排课问题展开分析和讨论,并给出了算法实现。在这些章的末尾,还给出了一些练习供读者深入学习和实践。第6章专门讨论了各种算法的优化问题。  

如何用Java实现遗传算法?

通过遗传算法走迷宫。虽然图1和图2均成功走出迷宫,但是图1比图2的路径长的多,且复杂,遗传算法可以计算出有多少种可能性,并选择其中最简洁的作为运算结果。

示例图1:

示例图2:

实现代码:

import java.util.ArrayList;

import java.util.Collections;

import java.util.Iterator;

import java.util.LinkedList;

import java.util.List;

import java.util.Random;

/**

* 用遗传算法走迷宫

*

* @author Orisun

*

*/

public class GA {

int gene_len; // 基因长度

int chrom_len; // 染色体长度

int population; // 种群大小

double cross_ratio; // 交叉率

double muta_ratio; // 变异率

int iter_limit; // 最多进化的代数

Listboolean[] individuals; // 存储当代种群的染色体

Labyrinth labyrinth;

int width;      //迷宫一行有多少个格子

int height;     //迷宫有多少行

public class BI {

double fitness;

boolean[] indv;

public BI(double f, boolean[] ind) {

fitness = f;

indv = ind;

}

public double getFitness() {

return fitness;

}

public boolean[] getIndv() {

return indv;

}

}

ListBI best_individual; // 存储每一代中最优秀的个体

public GA(Labyrinth labyrinth) {

this.labyrinth=labyrinth;

this.width = labyrinth.map[0].length;

this.height = labyrinth.map.length;

chrom_len = 4 * (width+height);

gene_len = 2;

population = 20;

cross_ratio = 0.83;

muta_ratio = 0.002;

iter_limit = 300;

individuals = new ArrayListboolean[](population);

best_individual = new ArrayListBI(iter_limit);

}

public int getWidth() {

return width;

}

public void setWidth(int width) {

this.width = width;

}

public double getCross_ratio() {

return cross_ratio;

}

public ListBI getBest_individual() {

return best_individual;

}

public Labyrinth getLabyrinth() {

return labyrinth;

}

public void setLabyrinth(Labyrinth labyrinth) {

this.labyrinth = labyrinth;

}

public void setChrom_len(int chrom_len) {

this.chrom_len = chrom_len;

}

public void setPopulation(int population) {

this.population = population;

}

public void setCross_ratio(double cross_ratio) {

this.cross_ratio = cross_ratio;

}

public void setMuta_ratio(double muta_ratio) {

this.muta_ratio = muta_ratio;

}

public void setIter_limit(int iter_limit) {

this.iter_limit = iter_limit;

}

// 初始化种群

public void initPopulation() {

Random r = new Random(System.currentTimeMillis());

for (int i = 0; i population; i++) {

int len = gene_len * chrom_len;

boolean[] ind = new boolean[len];

for (int j = 0; j len; j++)

ind[j] = r.nextBoolean();

individuals.add(ind);

}

}

// 交叉

public void cross(boolean[] arr1, boolean[] arr2) {

Random r = new Random(System.currentTimeMillis());

int length = arr1.length;

int slice = 0;

do {

slice = r.nextInt(length);

} while (slice == 0);

if (slice length / 2) {

for (int i = 0; i slice; i++) {

boolean tmp = arr1[i];

arr1[i] = arr2[i];

arr2[i] = tmp;

}

} else {

for (int i = slice; i length; i++) {

boolean tmp = arr1[i];

arr1[i] = arr2[i];

arr2[i] = tmp;

}

}

}

// 变异

public void mutation(boolean[] individual) {

int length = individual.length;

Random r = new Random(System.currentTimeMillis());

individual[r.nextInt(length)] ^= false;

}

// 轮盘法选择下一代,并返回当代最高的适应度值

public double selection() {

boolean[][] next_generation = new boolean[population][]; // 下一代

int length = gene_len * chrom_len;

for (int i = 0; i population; i++)

next_generation[i] = new boolean[length];

double[] cumulation = new double[population];

int best_index = 0;

double max_fitness = getFitness(individuals.get(best_index));

cumulation[0] = max_fitness;

for (int i = 1; i population; i++) {

double fit = getFitness(individuals.get(i));

cumulation[i] = cumulation[i - 1] + fit;

// 寻找当代的最优个体

if (fit max_fitness) {

best_index = i;

max_fitness = fit;

}

}

Random rand = new Random(System.currentTimeMillis());

for (int i = 0; i population; i++)

next_generation[i] = individuals.get(findByHalf(cumulation,

rand.nextDouble() * cumulation[population - 1]));

// 把当代的最优个体及其适应度放到best_individual中

BI bi = new BI(max_fitness, individuals.get(best_index));

// printPath(individuals.get(best_index));

//System.out.println(max_fitness);

best_individual.add(bi);

// 新一代作为当前代

for (int i = 0; i population; i++)

individuals.set(i, next_generation[i]);

return max_fitness;

}

// 折半查找

public int findByHalf(double[] arr, double find) {

if (find  0 || find == 0 || find arr[arr.length - 1])

return -1;

int min = 0;

int max = arr.length - 1;

int medium = min;

do {

if (medium == (min + max) / 2)

break;

medium = (min + max) / 2;

if (arr[medium] find)

min = medium;

else if (arr[medium] find)

max = medium;

else

return medium;

} while (min max);

return max;

}

// 计算适应度

public double getFitness(boolean[] individual) {

int length = individual.length;

// 记录当前的位置,入口点是(1,0)

int x = 1;

int y = 0;

// 根据染色体中基因的指导向前走

for (int i = 0; i length; i++) {

boolean b1 = individual[i];

boolean b2 = individual[++i];

// 00向左走

if (b1 == false  b2 == false) {

if (x  0  labyrinth.map[y][x - 1] == true) {

x--;

}

}

// 01向右走

else if (b1 == false  b2 == true) {

if (x + 1  width labyrinth.map[y][x + 1] == true) {

x++;

}

}

// 10向上走

else if (b1 == true  b2 == false) {

if (y  0  labyrinth.map[y - 1][x] == true) {

y--;

}

}

// 11向下走

else if (b1 == true  b2 == true) {

if (y + 1  height labyrinth.map[y + 1][x] == true) {

y++;

}

}

}

int n = Math.abs(x - labyrinth.x_end) + Math.abs(y -labyrinth.y_end) + 1;

//      if(n==1)

//          printPath(individual);

return 1.0 / n;

}

// 运行遗传算法

public boolean run() {

// 初始化种群

initPopulation();

Random rand = new Random(System.currentTimeMillis());

boolean success = false;

while (iter_limit--  0) {

// 打乱种群的顺序

Collections.shuffle(individuals);

for (int i = 0; i population - 1; i += 2) {

// 交叉

if (rand.nextDouble() cross_ratio) {

cross(individuals.get(i), individuals.get(i + 1));

}

// 变异

if (rand.nextDouble() muta_ratio) {

mutation(individuals.get(i));

}

}

// 种群更替

if (selection() == 1) {

success = true;

break;

}

}

return success;

}

//  public static void main(String[] args) {

//      GA ga = new GA(8, 8);

//      if (!ga.run()) {

//          System.out.println("没有找到走出迷宫的路径.");

//      } else {

//          int gen = ga.best_individual.size();

//          boolean[] individual = ga.best_individual.get(gen - 1).indv;

//          System.out.println(ga.getPath(individual));

//      }

//  }

// 根据染色体打印走法

public String getPath(boolean[] individual) {

int length = individual.length;

int x = 1;

int y = 0;

LinkedListString stack=new LinkedListString();

for (int i = 0; i length; i++) {

boolean b1 = individual[i];

boolean b2 = individual[++i];

if (b1 == false  b2 == false) {

if (x  0  labyrinth.map[y][x - 1] == true) {

x--;

if(!stack.isEmpty() stack.peek()=="右")

stack.poll();

else

stack.push("左");

}

} else if (b1 == false  b2 == true) {

if (x + 1  width labyrinth.map[y][x + 1] == true) {

x++;

if(!stack.isEmpty() stack.peek()=="左")

stack.poll();

else

stack.push("右");

}

} else if (b1 == true  b2 == false) {

if (y  0  labyrinth.map[y - 1][x] == true) {

y--;

if(!stack.isEmpty() stack.peek()=="下")

stack.poll();

else

stack.push("上");

}

} else if (b1 == true  b2 == true) {

if (y + 1  height labyrinth.map[y + 1][x] == true) {

y++;

if(!stack.isEmpty() stack.peek()=="上")

stack.poll();

else

stack.push("下");

}

}

}

StringBuilder sb=new StringBuilder(length/4);

IteratorString iter=stack.descendingIterator();

while(iter.hasNext())

sb.append(iter.next());

return sb.toString();

}

}