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2025-09-04 14:09:06 +08:00
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package org.dromara.easyai.pso;
import org.dromara.easyai.i.PsoFunction;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
/**
* @param
* @DATA
* @Author LiDaPeng
* @Description 粒子群
*/
public class PSO {
private float globalValue = -1;//当前全局最优值
private int times;//迭代次数
private List<Particle> allPar = new ArrayList<>();//全部粒子集合
private PsoFunction psoFunction;//粒子群执行函数
private float inertialFactor = 0.5f;//惯性因子
private float selfStudyFactor = 2;//个体学习因子
private float socialStudyFactor = 2;//社会学习因子
private boolean isMax;//取最大值还是最小值
private float[] allBest;//全局最佳位置
private Random random = new Random();
private float[] minBorder, maxBorder;
private float maxSpeed;
private float initSpeed;//初始速度
/**
* 初始化
*
* @param dimensionNub 维度
* @param minBorder 最小边界
* @param maxBorder 最大边界
* @param times 迭代次数
* @param particleNub 粒子数量
* @param psoFunction 适应函数
* @param inertialFactor 惯性因子
* @param selfStudyFactor 个体学习因子
* @param socialStudyFactor 社会学习因子
* @param isMax 最大值是否为最优
* @param maxSpeed 最大速度
* @param initSpeed 初始速度
* @throws Exception
*/
public PSO(int dimensionNub, float[] minBorder, float[] maxBorder,
int times, int particleNub, PsoFunction psoFunction,
float inertialFactor, float selfStudyFactor, float socialStudyFactor
, boolean isMax, float maxSpeed, float initSpeed) {
this.initSpeed = initSpeed;
this.times = times;
this.psoFunction = psoFunction;
this.isMax = isMax;
allBest = new float[dimensionNub];
this.minBorder = minBorder;
this.maxBorder = maxBorder;
this.maxSpeed = maxSpeed;
if (inertialFactor > 0) {
this.inertialFactor = inertialFactor;
}
if (selfStudyFactor >= 0 && selfStudyFactor <= 4) {
this.selfStudyFactor = selfStudyFactor;
}
if (socialStudyFactor >= 0 && socialStudyFactor <= 4) {
this.socialStudyFactor = socialStudyFactor;
}
for (int i = 0; i < particleNub; i++) {//初始化生成粒子群
Particle particle = new Particle(dimensionNub);
allPar.add(particle);
}
}
public float[] getAllBest() {
return allBest;
}
public void setAllPar(List<Particle> allPar) {//外置粒子群注入
this.allPar = allPar;
}
public void start() throws Exception {//开始进行迭代
int size = allPar.size();
for (int i = 0; i < times; i++) {
for (int j = 0; j < size; j++) {
move(allPar.get(j), j);
}
}
//粒子群移动结束
// draw("/Users/lidapeng/Desktop/test/testOne/e2.jpg", fatherX, fatherY);
}
private void move(Particle particle, int id) throws Exception {//粒子群开始移动
float[] parameter = particle.getParameter();//当前粒子的位置
BestData[] bestData = particle.bestDataArray;//该粒子的信息
float value = psoFunction.getResult(parameter, id);
float selfValue = particle.selfBestValue;//局部最佳值
if (isMax) {//取最大值
if (value > globalValue) {//更新全局最大值
globalValue = value;
//更新全局最佳位置
for (int i = 0; i < allBest.length; i++) {
allBest[i] = parameter[i];
}
}
if (value > selfValue) {//更新局部最大值
particle.selfBestValue = value;
//更新局部最佳位置
for (int i = 0; i < bestData.length; i++) {
bestData[i].selfBestPosition = parameter[i];
}
}
} else {//取最小值
if (globalValue < 0 || value < globalValue) {//更新全局最小值
globalValue = value;
//更新全局最佳位置
for (int i = 0; i < allBest.length; i++) {
allBest[i] = parameter[i];
}
}
if (selfValue < 0 || value < selfValue) {//更新全局最小值
particle.selfBestValue = value;
//更新局部最佳位置
for (int i = 0; i < bestData.length; i++) {
bestData[i].selfBestPosition = parameter[i];
}
}
}
//先更新粒子每个维度的速度
for (int i = 0; i < bestData.length; i++) {
float speed = bestData[i].speed;//当前维度的速度
float pid = bestData[i].selfBestPosition;//当前自己的最佳位置
float selfPosition = parameter[i];//当前自己的位置
float pgd = allBest[i];//当前维度的全局最佳位置
//当前维度更新后的速度
speed = inertialFactor * speed + selfStudyFactor * random.nextFloat() * (pid - selfPosition)
+ socialStudyFactor * random.nextFloat() * (pgd - selfPosition);
if ((float)Math.abs(speed) > maxSpeed) {
if (speed > 0) {
speed = maxSpeed;
} else {
speed = -maxSpeed;
}
}
bestData[i].speed = speed;
//更新该粒子该维度新的位置
float position = selfPosition + speed;
if (minBorder != null) {
if (position < minBorder[i]) {
position = minBorder[i];
}
if (position > maxBorder[i]) {
position = maxBorder[i];
}
}
bestData[i].selfPosition = position;
}
}
class Particle {//粒子
private BestData[] bestDataArray;
private float selfBestValue = -1;//自身最优的值
private float[] getParameter() {//获取粒子位置信息
float[] parameter = new float[bestDataArray.length];
for (int i = 0; i < parameter.length; i++) {
parameter[i] = bestDataArray[i].selfPosition;
}
return parameter;
}
protected Particle(int dimensionNub) {//初始化随机位置
bestDataArray = new BestData[dimensionNub];
for (int i = 0; i < dimensionNub; i++) {
float position;
if (minBorder != null && maxBorder != null) {
float min = minBorder[i];
float max = maxBorder[i];
float region = max - min + 1;
position = random.nextInt((int) region) + min;//初始化该维度的位置
} else {
position = random.nextFloat();
}
bestDataArray[i] = new BestData(position, initSpeed);
}
}
}
class BestData {//数据保存
private BestData(float selfPosition, float initSpeed) {
this.selfBestPosition = selfPosition;
this.selfPosition = selfPosition;
speed = initSpeed;
}
private float speed;//该粒子当前维度的速度
private float selfBestPosition;//当前维度自身最优的历史位置/自己最优位置的值
private float selfPosition;//当前维度自己现在的位置/也就是当前维度自己的值
}
}