蝙蝠算法求解函数最大值python
时间: 2023-08-31 15:12:23 浏览: 141
以下是使用蝙蝠算法求解函数最大值的Python代码示例:
```python
import random
import math
# 定义目标函数
def objective_function(x):
return math.sin(x)
# 定义蝙蝠算法函数
def bat_algorithm(function, dimension, population_size, iteration, A, r, Qmin, Qmax):
# 初始化种群
population = [[random.uniform(-10, 10) for j in range(dimension)] for i in range(population_size)]
# 初始化速度和频率
velocity = [[0 for j in range(dimension)] for i in range(population_size)]
frequency = [0 for i in range(population_size)]
# 初始化最优解和最优值
best_solution = population[0]
best_fitness = function(best_solution[0])
# 开始迭代
for t in range(iteration):
for i in range(population_size):
# 随机选择另一个个体
j = random.randint(0, population_size - 1)
# 随机生成新解
for k in range(dimension):
velocity[i][k] = velocity[i][k] + (population[i][k] - best_solution[k]) * frequency[i]
population[i][k] = population[i][k] + velocity[i][k]
if population[i][k] < -10:
population[i][k] = -10
elif population[i][k] > 10:
population[i][k] = 10
# 判断是否更新最优解
fitness = function(population[i][0])
if fitness > best_fitness:
best_solution = population[i]
best_fitness = fitness
# 更新频率和脉冲率
frequency[i] = Qmin + (Qmax - Qmin) * random.random()
pulse_rate = A * math.exp(-r * t)
if random.random() > pulse_rate:
for k in range(dimension):
population[i][k] = best_solution[k] + 0.001 * random.gauss(0, 1)
return best_solution, best_fitness
# 测试蝙蝠算法
best_solution, best_fitness = bat_algorithm(objective_function, 1, 50, 100, 0.5, 0.5, 0.0, 1.0)
print("Best solution:", best_solution)
print("Best fitness:", best_fitness)
```
上述代码中,目标函数为 sin(x),蝙蝠算法函数 `bat_algorithm` 中的参数含义如下:
- `function`:目标函数
- `dimension`:解向量的维度,这里为 1
- `population_size`:种群大小
- `iteration`:迭代次数
- `A`:脉冲率,控制蝙蝠飞行速度的大小
- `r`:控制脉冲率的衰减速度
- `Qmin`:最小频率
- `Qmax`:最大频率
在测试蝙蝠算法时,使用了种群大小为 50,迭代次数为 100,脉冲率为 0.5,脉冲率衰减速度为 0.5,最小频率为 0.0,最大频率为 1.0。最终输出最优解和最优值。
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