PHP中的蚁群算法详解

class Ant {
    public $path;
    public $visitedCities;
    public $currentCity;
    
    public function __construct($startCity) {
        $this->path = [];
        $this->visitedCities = [];
        $this->currentCity = $startCity;
        
        $this->visitedCities[] = $startCity;
        $this->path[] = $startCity;
    }
    
    public function chooseNextCity($pheromones, $distances) {
        // 根据信息素和距离计算下一步要选择的城市
        // ...
    }
    
    public function updatePath($city) {
        // 更新路径和访问过的城市列表
        // ...
    }
}

class AntColonyAlgorithm {
    public $pheromones;
    public $distances;
    public $ants;
    public $bestPath;
    public $bestDistance;
    
    public function __construct($pheromones, $distances) {
        $this->pheromones = $pheromones;
        $this->distances = $distances;
        $this->ants = [];
        $this->bestPath = [];
        $this->bestDistance = PHP_INT_MAX;
    }
    
    public function start($startCity, $numAnts, $iterations) {
        // 初始化蚂蚁群
        // ...
        
        for ($i = 0; $i < $iterations; $i++) {
            // 每个蚂蚁进行路径选择
            // ...
            
            // 更新信息素
            // ...
            
            // 更新全局最优解
            // ...
        }
        
        return [$this->bestPath, $this->bestDistance];
    }
    
    public function evaporatePheromones() {
        // 信息素蒸发
        // ...
    }
    
    public function depositPheromones() {
        // 信息素沉积
        // ...
    }
}

// 初始化信息素和距离
$pheromones = [
    [0, 0.5, 0.2],
    [0.5, 0, 0.7],
    [0.2, 0.7, 0]
];

$distances = [
    [0, 10, 20],
    [10, 0, 5],
    [20, 5, 0]
];

// 创建蚁群算法实例
$aco = new AntColonyAlgorithm($pheromones, $distances);

// 启动算法
$startCity = 0;
$numAnts = 5;
$iterations = 10;
list($bestPath, $bestDistance) = $aco->start($startCity, $numAnts, $iterations);

// 输出结果
echo "最优路径: ".implode(" -> ", $bestPath)."<br>";
echo "最优解: ".$bestDistance;