python实现MFOA算法
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MFOA(Multi-Objective Firefly Algorithm)是一种多目标优化算法,它基于萤火虫算法(Firefly Algorithm)并进行了改进。下面是Python实现MFOA算法的示例代码:
```python
import numpy as np
import math
# 定义目标函数
def obj_func(x):
f1 = x[0]**2 + x[1]**2
f2 = (x[0]-1)**2 + x[1]**2
return [f1, f2]
# 定义MFOA算法
def mfoa(obj_func, lb, ub, dimension, n_objectives, n_fireflies, n_iterations):
# 初始化
alpha = 0.5 # 镜面反射系数
gamma = 1 # 光吸收系数
beta0 = 1 # 初始亮度
beta_min = 0.2 # 最小亮度
# 初始化萤火虫位置和亮度
x = np.random.uniform(lb, ub, (n_fireflies, dimension))
y = np.zeros((n_fireflies, n_objectives))
for i in range(n_fireflies):
y[i] = obj_func(x[i])
# 迭代优化
for t in range(n_iterations):
# 计算亮度和吸引度
beta = beta0 * math.exp(-gamma * t)
for i in range(n_fireflies):
for j in range(n_fireflies):
if i == j:
continue
dist = np.linalg.norm(x[i] - x[j])
if y[i][0] < y[j][0] and y[i][1] < y[j][1]:
# 亮度越大,吸引度越强
y[i] += beta * math.exp(-dist**2 / alpha) * (y[j]-y[i])
x[i] += y[i] * np.random.uniform(0, 1, dimension)
else:
y[i] += beta_min * math.exp(-dist**2 / alpha) * (y[j]-y[i])
x[i] += y[i] * np.random.uniform(0, 1, dimension)
# 限制解空间
for i in range(n_fireflies):
for j in range(dimension):
if x[i][j] < lb[j]:
x[i][j] = lb[j]
elif x[i][j] > ub[j]:
x[i][j] = ub[j]
y[i] = obj_func(x[i])
# 返回最优解
best_index = np.argmin(y[:, 0] + y[:, 1])
return x[best_index], y[best_index]
# 示例
lb = [-5, -5]
ub = [5, 5]
dimension = 2
n_objectives = 2
n_fireflies = 40
n_iterations = 100
best_x, best_y = mfoa(obj_func, lb, ub, dimension, n_objectives, n_fireflies, n_iterations)
print('最优解:', best_x)
print('目标函数值:', best_y)
```
在示例中,定义了一个二维的目标函数,它有两个目标:f1 = x[0]**2 + x[1]**2 和 f2 = (x[0]-1)**2 + x[1]**2。然后调用mfoa函数进行优化,传入目标函数、解空间的下限和上限、维度、目标数、萤火虫数量和迭代次数等参数。最后返回最优解和目标函数值。
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