遗传编程GP-地图路径寻路

本文介绍的是基于GP，并非A*算法，算是另类实现吧。

先看看地图定义，在文本文件中定义如下字符串，代表30列11行大小的地图

初始位置在左上角（0,0） ，值为1的是允许走的通的路，目标位置为右下角（29,10）

1 1 1 1 1 1 1 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0  0 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0  1 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0  0 0 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 1 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0  0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 1 1 1 1 1 1 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0  0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0  0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 　　

算法运行效果如下：

"C:\Program Files\Java\jdk1.8.0_211\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.1.2\lib\idea_rt.jar=54171:C:\Program Files\JetBrains\IntelliJ IDEA 2019.1.2\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_211\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_211\jre\lib\rt.jar;C:\Research-Code\demo1\target\classes;C:\Users\McKay\.m2\repository\io\jenetics\jenetics\5.1.0\jenetics-5.1.0.jar;C:\Users\McKay\.m2\repository\io\jenetics\jenetics.ext\5.1.0\jenetics.ext-5.1.0.jar;C:\Users\McKay\.m2\repository\io\jenetics\jenetics.prog\5.1.0\jenetics.prog-5.1.0.jar;C:\Users\McKay\.m2\repository\commons-lang\commons-lang\2.6\commons-lang-2.6.jar" MapGame.GameDemo
1 1 1 1 1 1 1 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 1 1 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 1 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
0 0 0 1 1 1 1 1 1 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
G: 15769
--------------------
map-->Right-->Right-->Right-->Right-->Right-->Down-->Down-->Down-->Left-->Down-->Down-->Left-->Down-->Down-->Right-->Right-->Right-->Right-->Right-->Down-->Down-->Down-->Right-->Right-->Right-->Right-->Right-->Right-->Right-->Right-->Right-->Right-->
E: 1320.0

Process finished with exit code 0

这边由于是套遗传编程，因此会定义几个固定操作算子：上移、下移、左移、右移；看看上移算子代码：

public class GoUpOp implements Op<TempMapInfo> {
    private MapController mapController;　　　　　　　　　　　　　　//地图控制工具类，比如判断能否移动到某个坐标、是否完成地图等
    public GoUpOp(MapController mapController) {
        this.mapController=mapController;
    }

    @Override
    public String name() {
        return "Up";
    }

    @Override
    public int arity() {
        return 1;
    }

    @Override
    public String toString() {
        return "Up";
    }

    @Override
    public TempMapInfo apply(TempMapInfo[] tempMapInfos) {
        TempMapInfo newInfo=tempMapInfos[0].cloneMe();　　　　　　　　//需要深度克隆，防止多线程对象直接互相影响

        if(newInfo.currentLocationY==0)
        {
            newInfo.score-=1000;　　　　　　　　　　　　　　　　　　　　　　//已经在最上方了，不能再做上移动作了
            newInfo.tag+="-UP";　　　　　　　　　　　　　　　　　　　　　　 //惩罚分，扣除1000分
            return newInfo;
        }
        if(!mapController.canMove2(newInfo.currentLocationX, newInfo.currentLocationY-1))　　　　//是否上移位置是路
        {
            newInfo.score-=1000;　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　//惩罚扣除1000分
            newInfo.tag+="-UP";
            return newInfo;
        }

        newInfo.score+=10;　　　　　　　　　　　　　　　　　　　　　　//可以走，奖励10分
        newInfo.currentLocationY--;　　　　　　　　　　　　　　　　 //递减y坐标
        if(newInfo.visited.contains(newInfo.currentLocationX+","+newInfo.currentLocationY))　　　　//不能重复访问点
            newInfo.score-=1000;
        else
            newInfo.visited.add(newInfo.currentLocationX+","+newInfo.currentLocationY);

        if(mapController.isSuccess(newInfo.currentLocationX, newInfo.currentLocationY))　　　　　　//判断是否地图完成
            newInfo.score+=1000;
        newInfo.tag+="-UP";
        return newInfo;
    }

}　　

　　

下面需要将这些操作算子嵌进GP中：

public static void main(String[] args) {

        Integer[][] map=GetMap();
        dispalyMap(map);

        TempMapInfo mapInfo=new TempMapInfo();
        mapInfo.score=0;
        mapInfo.currentLocationX=0;
        mapInfo.currentLocationY=0;　　　　　　　　　　//左上角为起点

        List<Op<TempMapInfo>> terminals=new ArrayList<>();
        terminals.add(Const.of("map", mapInfo));

        MapController mapController=new MapController(map);

        final ISeq<Op<TempMapInfo>> TMS = ISeq.of(terminals);
        final ISeq<Op<TempMapInfo>> OPS = ISeq.of(new GoLeftOp(mapController), new GoRightOp(mapController), new GoUpOp(mapController), new GoDownOp(mapController));
        final GameSearcher gameSearcher =  GameSearcher.of(
                                                            GameSearcher.codecOf(
                                                                    OPS, TMS, 20,
                                                                    t -> t.getGene().size() < 60
                                                            )
                                                );

        final Engine<ProgramGene<TempMapInfo>, Double> engine = Engine
                .builder(gameSearcher)
                .populationSize(500)
                .maximizing()
                .alterers(
                        new SingleNodeCrossover<>(0.1),
                        new Mutator<>(0.3),
                        new UniformCrossover<>(0.5)
                )
                .offspringSelector(new TournamentSelector<>(2))
                .survivorsSelector(new TournamentSelector<>())
                .build();

        final EvolutionResult<ProgramGene<TempMapInfo>, Double> er =
                engine.stream()
                        .limit(Limits.byExecutionTime(Duration.ofSeconds(60)))
                        .collect(EvolutionResult.toBestEvolutionResult());

        final ProgramGene<TempMapInfo> program = er.getBestPhenotype()
                .getGenotype()
                .getGene();

        final TreeNode<Op<TempMapInfo>> tree = program.toTreeNode();
        System.out.println("G: " + er.getTotalGenerations());
        printTree(tree.depthFirstStream().collect(Collectors.toList()));
        System.out.println("E: " + gameSearcher._fitness(tree));
    }

    private static void printTree(List<TreeNode<Op<TempMapInfo>>> lst) {
        System.out.println("--------------------");
        for(TreeNode<Op<TempMapInfo>> node:lst)
            System.out.print(node.getValue()+"-->");
        System.out.println();
    }　　

上面的terminals变量是存放终结符的，此处是直接把操作动作放进去了，包含了分数、访问步骤、当前xy坐标等，只有1个变量

public class TempMapInfo {
    public int currentLocationX;
    public int currentLocationY;
    public double score;
    public List<String> visited=new ArrayList<>();
    public String tag="";

    public TempMapInfo()
    {
        visited.add("0,0");
    }

    public TempMapInfo cloneMe()
    {
        TempMapInfo info=new TempMapInfo();

        info.currentLocationX=this.currentLocationX;
        info.currentLocationY=this.currentLocationY;
        info.score=this.score;
        info.tag=this.tag;
        info.visited=new ArrayList<>();
        for(String i:this.visited)
            info.visited.add(i);

        return info;
    }
}

　　

GameSearcher是对GP算法的编码、解码封装、计算分值，算是核心：

public final class GameSearcher
	implements Problem<Tree<Op<TempMapInfo>, ?>, ProgramGene<TempMapInfo>, Double>
{

	private final Codec<Tree<Op<TempMapInfo>, ?>, ProgramGene<TempMapInfo>> _codec;

	private GameSearcher(
		final Codec<Tree<Op<TempMapInfo>, ?>, ProgramGene<TempMapInfo>> codec
	) {
		_codec = requireNonNull(codec);
	}

	@Override
	public Function<Tree<Op<TempMapInfo>, ?>, Double> fitness() {
		return this::_fitness;
	}

	@Override
	public Codec<Tree<Op<TempMapInfo>, ?>, ProgramGene<TempMapInfo>> codec() {
		return _codec;
	}

	public double _fitness(final Tree<Op<TempMapInfo>, ?> program) {

		List<TempMapInfo> lst=new ArrayList<>();
		lst.add(new TempMapInfo());

		List<TempMapInfo> results=lst.stream().map(args -> Program.eval(program, args)).collect(Collectors.toList());

		double score=results.stream().mapToDouble(a->a.score).sum();　　　　　　　　　　　　　　//这行是用来统计整个操作算子序列总得分用的，很重要
		return score;
	}

	public static GameSearcher of(
		final Codec<Tree<Op<TempMapInfo>, ?>, ProgramGene<TempMapInfo>> codec
	) {
		return new GameSearcher(codec);
	}

	public static Codec<Tree<Op<TempMapInfo>, ?>, ProgramGene<TempMapInfo>>
	codecOf(
		final ISeq<Op<TempMapInfo>> operations,
		final ISeq<Op<TempMapInfo>> terminals,
		final int depth,
		final Predicate<? super ProgramChromosome<TempMapInfo>> validator
	) {
		if (depth > 200 || depth < 0) {
			throw new IllegalArgumentException(format(
				"Tree depth out of range [0, 30): %d", depth
			));
		}

		return Codec.of(
			Genotype.of(ProgramChromosome.of(
				depth,
				validator,
				operations,
				terminals
			)),
			Genotype::getGene
		);
	}
}

　　

算法介绍完毕，pom依赖如下：

<dependencies>
        <!-- https://mvnrepository.com/artifact/io.jenetics/jenetics -->
        <dependency>
            <groupId>io.jenetics</groupId>
            <artifactId>jenetics</artifactId>
            <version>5.1.0</version>
        </dependency>
        <dependency>
            <groupId>io.jenetics</groupId>
            <artifactId>jenetics.ext</artifactId>
            <version>5.1.0</version>
        </dependency>
        <dependency>
            <groupId>io.jenetics</groupId>
            <artifactId>jenetics.prog</artifactId>
            <version>5.1.0</version>
        </dependency>
        <dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>
    </dependencies>