java – 使用Repast Simphony的意外结果

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我需要使用Repast Simphony作为模拟器开发 Java版本的迭代囚徒困境.

这些想法是每个玩家都是一个代理人,我们有一个无法移动的n x n播放器网格.每个玩家必须与4个邻居(北部,南部,西部和东部)玩,根据每轮中4种不同游戏的结果找到最佳策略.

由于没有内置系统在Repast Simphony中的代理之间交换消息,我必须实施某种解决方法来处理代理的同步(A vs B和B vs A应该算作同一轮,这就是他们需要的原因要同步).

这是通过将每一轮视为:

>玩家我为4个敌人中的每一个选择下一步行动
>玩家我向4个敌人中的每一个发送正确的动作
>玩家我等待4个敌人中的每一个回复

根据我对Repast Simphony的理解,预定的方法是顺序的(没有代理级并行),这意味着我被迫以与发送方式不同的方式进行等待(以较低的pritority安排以确保完成所有发送)在开始等待之前).

这里的问题是,尽管收到了所有4条预期的消息(至少这是打印的内容),一旦等待方法启动它报告的接收元素少于4个.

这是从Player类中获取代码

// myPoint is the location inside the grid (unique,agents can't move and only one per cell is allowed)
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((myPoint == null) ? 0 : myPoint.hashCode());
    return result;
}

// Returns enemy's choice in the prevIoUs round
private byte getLastPlay(Player enemy) {
    return (neighbors.get(enemy)[1]) ? COOPERATE : DEFECT;
}

// Elements are saved as (player,choice)
private void receivePlay(Player enemy,byte play) {
    System.out.println(this + " receives (" + play + ") from " + enemy);
    while (!playSharedQueue.add(new Object[] { enemy,play })){
        // This doesn't get printed,meaning that the insertion is successful!
        System.out.println(this + " Failed inserting");
    }
}

@ScheduledMethod(start = 1,interval = 1,priority = 10)
public void play() {
    System.out.println(this + " started playing");
    // Clear prevIoUs plays
    playSharedQueue.clear();
    for (Player enemy : neighbors.keySet()) {
        // properties[0] = true if we already played together
        // properties[1] = true if enemy choose to cooperate on the prevIoUs round
        Boolean[] properties = neighbors.get(enemy);
        // Choose which side we take this time
        byte myPlay;
        if (properties[0]) {
            // First time that we play,use memory-less strategy
            myPlay = (Math.random() <= strategy[0]) ? COOPERATE : DEFECT;
            // Report that we played
            properties[0] = false;
            neighbors.put(enemy,properties);
        } else {
            // We already had a round,use strategy with memory
            byte enemyLastPlay = enemy.getLastPlay(this);
            // Choose which side to take based on enemy's prevIoUs decision
            myPlay = (Math.random() <= strategy[(enemyLastPlay) == COOPERATE ? 1 : 2]) ? COOPERATE : DEFECT;
        }
        // Send my choice to the enemy
        System.out.println(this + " sent (" + myPlay + ") to " + enemy);
        enemy.receivePlay(this,myPlay);
    }
}

// Waits for the results and processes them
@ScheduledMethod(start = 1,priority = 5)
public void waitResults() {
    // Clear prevIoUs score
    lastPayoff = 0;
    System.out.println(this + " waits for results [" + playSharedQueue.size() + "]");
    if (playSharedQueue.size() != 4) {
        // Well,this happens on the first agent :(
        System.exit(1);
    }
    // ... process ...
}

这是控制台输出,因此您可以看到所有内容似乎都没有问题地发送和接收(使用3 x 3网格):

Player[2,0] started playing
Player[2,0] sent (0) to Player[2,1]
Player[2,1] receives (0) from Player[2,0]
Player[2,2]
Player[2,2] receives (0) from Player[2,0] sent (0) to Player[0,0]
Player[0,0] receives (0) from Player[2,0] sent (0) to Player[1,0]
Player[1,2] started playing
Player[1,2] sent (1) to Player[2,2] receives (1) from Player[1,2]
Player[1,2] sent (1) to Player[0,2]
Player[0,2] sent (1) to Player[1,0] receives (1) from Player[1,1]
Player[1,1] receives (1) from Player[1,2] started playing
Player[0,2] receives (1) from Player[0,0] receives (1) from Player[0,1]
Player[0,1] receives (1) from Player[0,1] started playing
Player[0,1] sent (1) to Player[2,1] sent (1) to Player[0,1] sent (1) to Player[1,0] started playing
Player[1,0] receives (0) from Player[1,1] receives (0) from Player[1,2] receives (0) from Player[1,1] started playing
Player[1,1] sent (0) to Player[2,1] sent (0) to Player[0,1] sent (0) to Player[1,2] started playing
Player[2,2] sent (0) to Player[2,2] sent (0) to Player[0,2] sent (0) to Player[1,0] started playing
Player[0,0] sent (1) to Player[2,0] sent (1) to Player[0,0] sent (1) to Player[1,1] started playing
Player[2,0] receives (1) from Player[2,2] receives (1) from Player[2,1] receives (1) from Player[2,2] waits for results [1]

正如你在最后一行中看到的那样,playSharedQueue.size()是1,我真的不明白为什么.

如果方法调用是顺序的,则在9play()`执行后调用waitResults()方法,并且假设每个正确发送4条消息,我找不到该大小仍为1的原因.

当然,所有顺序意味着没有同步问题,即使我使用LinkedBlockingQueue而不是HashSet也有同样的问题.

你们有什么暗示吗?

解决方法

过了一段时间,我再次打开代码,发现我做了一个简单而严重的错误
@ScheduledMethod(start = 1,priority = 10)
public void play() {
    System.out.println(this + " started playing");
    // Clear prevIoUs plays
    playSharedQueue.clear();

playSharedQueue.clear();执行以清除先前的结果,但由于调用是连续的,第二个玩家将在第一个玩家向他发送他的游戏后调用它,以便放弃游戏.

在waitResults结束时移动该行解决了它.

原文链接:https://www.f2er.com/java/129970.html

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