萤火虫算法 python代码

萤火虫优化算法（Firefly Algorithm, FA）是一种模拟生物群体行为的全局搜索优化算法，灵感来源于萤火虫寻找配偶的行为。在Python中实现该算法，你可以按照以下步骤编写：

import numpy as np
import random

# 定义萤火虫类
class Firefly:
    def __init__(self, lower_bound, upper_bound, alpha=0.9, beta=1):
        self.position = np.random.uniform(lower_bound, upper_bound)
        self.intensity = np.random.uniform(0, 1)
        self.alpha = alpha
        self.beta = beta

    # 更新位置和亮度函数
    def update(self, fireflies, distance_matrix):
        for other in fireflies:
            if other.intensity > self.intensity:
                r = distance_matrix[self.id, other.id]
                new_intens = self.intensity + self.alpha * (other.intensity - self.intensity) * np.exp(-r**2 / self.beta)
                self.intensity = min(max(new_intens, 0), 1)  # 保持在[0,1]范围内
                new_pos = self.position + self.intensity * (other.position - self.position)
                self.position = np.clip(new_pos, a_min=lower_bound, a_max=upper_bound)

# 主程序
def firefly_algorithm(firefly_num, max_iter, lower_bound, upper_bound, distance_metric):
    fireflies = [Firefly(lower_bound, upper_bound) for _ in range(firefly_num)]
    distance_matrix = calculate_distance_matrix(fireflies, lower_bound, upper_bound, distance_metric)

    for _ in range(max_iter):
        for firefly in fireflies:
            firefly.update(fireflies, distance_matrix)

    best_firefly = sorted(fireflies, key=lambda x: x.intensity)[0]
    return best_firefly.position, best_firefly.intensity

# 计算距离矩阵
def calculate_distance_matrix(fireflies, lower_bound, upper_bound, metric):
    matrix = np.zeros((len(fireflies), len(fireflies)))
    for i, f1 in enumerate(fireflies):
        for j, f2 in enumerate(fireflies):
            matrix[i, j] = metric(f1.position, f2.position, lower_bound, upper_bound)
    return matrix

# 使用欧氏距离作为例子
def euclidean_distance(p1, p2, lb, ub):
    return np.sqrt(np.sum((p1 - p2)**2))

max_iter = 100  # 设置最大迭代次数
firefly_num = 50  # 设置萤火虫数量
lower_bound, upper_bound = (-10, 10)  # 搜索范围
best_position, best_intensity = firefly_algorithm(firefly_num, max_iter, lower_bound, upper_bound, euclidean_distance)

print("最优解：", best_position, "，亮度：", best_intensity)