$$ f=\alpha C_1L\sum_{k=1}^K{\frac{1}{t_k}}+\beta C_2\sum_{k=1}^K{\sum_{j=1}^J{\left( \frac{V_{kj}t_k}{2} \right)}} $$、$$ c\cdot \frac{\sum_{k=1}^K{\sum_{j=1}^J{V_{kj}}}}{\sum_{k=1}^K{\frac{1}{t_k}}}>c_1L $$,alpha、beta、c、c1、c2、L、K、J、V为自定义常量,t为K个元素的数组,5<t<30,用Python求最小值f多目标遗传算法代码
时间: 2023-06-17 22:02:27 浏览: 72
以下是用Python实现多目标遗传算法求解最小值f的代码:
```python
import random
import numpy as np
# 自定义常量
alpha = 0.5
beta = 0.5
c = 1.0
c1 = 1.0
c2 = 1.0
L = 1.0
K = 10
J = 5
V = np.random.random((K, J))
# 定义解的类
class Solution:
def __init__(self, t):
self.t = t
self.f1 = alpha * c1 * L * np.sum(1 / t) + beta * c2 * np.sum(V * t / 2)
self.f2 = c * np.sum(V) / np.sum(1 / t)
# 初始化种群
def init_population(pop_size):
population = []
for i in range(pop_size):
t = np.random.uniform(5, 30, size=K)
population.append(Solution(t))
return population
# 计算每个解的适应度值
def cal_fitness(solution):
return solution.f1, solution.f2
# 计算种群中每个解的适应度值
def cal_pop_fitness(population):
fitness = []
for solution in population:
fitness.append(cal_fitness(solution))
return np.array(fitness)
# 选择操作
def selection(population, fitness, num_parents):
parents = np.empty((num_parents, K))
for i in range(num_parents):
idx = np.random.choice(len(population), size=2, replace=False)
if fitness[idx[0]][0] < fitness[idx[1]][0] and fitness[idx[0]][1] < fitness[idx[1]][1]:
parents[i] = population[idx[0]].t
elif fitness[idx[0]][0] > fitness[idx[1]][0] and fitness[idx[0]][1] > fitness[idx[1]][1]:
parents[i] = population[idx[1]].t
elif fitness[idx[0]][0] / fitness[idx[0]][1] < fitness[idx[1]][0] / fitness[idx[1]][1]:
parents[i] = population[idx[0]].t
else:
parents[i] = population[idx[1]].t
return parents
# 交叉操作
def crossover(parents, offspring_size):
offspring = np.empty(offspring_size)
for i in range(offspring_size[0]):
idx = np.random.choice(len(parents), size=2, replace=False)
crossover_point = np.random.randint(1, K - 1)
offspring[i, 0:crossover_point] = parents[idx[0], 0:crossover_point]
offspring[i, crossover_point:] = parents[idx[1], crossover_point:]
return offspring
# 变异操作
def mutation(offspring_crossover, mutation_rate):
for i in range(offspring_crossover.shape[0]):
for j in range(offspring_crossover.shape[1]):
if random.random() < mutation_rate:
offspring_crossover[i, j] = np.random.uniform(5, 30)
return offspring_crossover
# 多目标遗传算法
def mo_ga(pop_size, num_generations, num_parents, mutation_rate):
population = init_population(pop_size)
for generation in range(num_generations):
fitness = cal_pop_fitness(population)
parents = selection(population, fitness, num_parents)
offspring_crossover = crossover(parents, (pop_size - num_parents, K))
offspring_mutation = mutation(offspring_crossover, mutation_rate)
population[0:num_parents] = parents
population[num_parents:] = [Solution(t) for t in offspring_mutation]
return population
# 测试
pop_size = 50
num_generations = 100
num_parents = 20
mutation_rate = 0.1
population = mo_ga(pop_size, num_generations, num_parents, mutation_rate)
fitness = cal_pop_fitness(population)
idx = np.argmin(fitness[:, 0] + fitness[:, 1])
print("最小值:", population[idx].f1, population[idx].f2)
print("对应的t:", population[idx].t)
```
其中,init_population()函数用于初始化种群,cal_fitness()函数用于计算每个解的适应度值,cal_pop_fitness()函数用于计算种群中每个解的适应度值,selection()函数用于进行选择操作,crossover()函数用于进行交叉操作,mutation()函数用于进行变异操作,mo_ga()函数用于实现多目标遗传算法的主体流程。最后,我们可以调用mo_ga()函数得到最优解的t值以及对应的最小值f。
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