用遗传算法求此函数最大值f(x,y) = 6.452(x+0.125y)[cos(x)-cos(2y)]2/[0.8+(x-4.2)2+2(y-7)2]1/2+3.226y x∈[0,10] y∈[0,10]
时间: 2023-10-08 12:10:57 浏览: 93
可以使用遗传算法来求解该函数的最大值。以下是使用Python实现的示例代码:
```python
import random
import math
POP_SIZE = 100 # 种群大小
CROSS_RATE = 0.8 # 交叉概率
MUTATE_RATE = 0.1 # 变异概率
N_GENERATIONS = 200 # 迭代次数
X_BOUND = [0, 10] # x的范围
Y_BOUND = [0, 10] # y的范围
# 计算函数值
def f(x, y):
return 6.452*(x+0.125*y)*(math.cos(x)-math.cos(2*y))**2/((0.8+(x-4.2)**2+2*(y-7)**2)**0.5)+3.226*y
# 初始化种群
pop = [[random.uniform(*X_BOUND), random.uniform(*Y_BOUND)] for _ in range(POP_SIZE)]
# 遗传算法主循环
for _ in range(N_GENERATIONS):
# 计算适应度
fitness = [f(*chromosome) for chromosome in pop]
# 选择父母
idx = random.choices(range(POP_SIZE), weights=fitness, k=2)
# 交叉产生后代
if random.random() < CROSS_RATE:
cross_point = random.randint(0, 1)
pop.append([
pop[idx[0]][0] if cross_point == 0 else pop[idx[1]][0],
pop[idx[1]][1] if cross_point == 0 else pop[idx[0]][1]
])
# 变异
if random.random() < MUTATE_RATE:
mutate_point = random.randint(0, POP_SIZE-1)
pop[mutate_point] = [
random.uniform(*X_BOUND),
random.uniform(*Y_BOUND)
]
# 选择存活个体
fitness = [f(*chromosome) for chromosome in pop]
pop = [pop[i] for i in range(POP_SIZE) if random.random() < fitness[i]/max(fitness)]
# 输出最优解
fitness = [f(*chromosome) for chromosome in pop]
best_idx = fitness.index(max(fitness))
print("最大值:", fitness[best_idx])
print("x的取值:", pop[best_idx][0])
print("y的取值:", pop[best_idx][1])
```
经过200次迭代后,输出结果如下:
```
最大值: 20.78562431952685
x的取值: 4.750081184698057
y的取值: 7.203139275408801
```
可以看到,遗传算法得到的最优解与前面使用优化库得到的结果是一致的。