在上面NSGA-II算法求解的代码中,若数据是直接写在代码中的,完整的代码该是什么
时间: 2024-03-26 15:34:23 浏览: 160
NSGA-II求解ZDT1函数matlab代码1.zip
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好的,以下是一个使用 NSGA-II 算法求解多目标优化问题的 Python 代码示例,其中数据是直接写在代码中的:
```python
import random
import math
# 定义问题
# 目标1: 最小化函数f1(x)
# 目标2: 最小化函数f2(x)
def problem(x):
f1 = x[0]**2 + x[1]**2
f2 = (x[0]-1)**2 + x[1]**2
return (f1, f2)
# 定义NSGA-II算法
def nsga2(popsize, generations, bounds):
# 初始化种群
pop = []
for i in range(popsize):
indv = []
for j in range(len(bounds)):
indv.append(random.uniform(bounds[j][0],bounds[j][1]))
pop.append(indv)
# 循环迭代
for gen in range(generations):
# 计算适应度
fitvals = []
for indv in pop:
fitvals.append(problem(indv))
# 计算拥挤程度
crowding = []
for i in range(len(pop)):
crowding.append(0)
for i in range(len(bounds)):
newpop = sorted(pop, key=lambda x:x[i])
crowding[0] = math.inf
crowding[-1] = math.inf
for j in range(1, len(pop)-1):
crowding[j] += (newpop[j+1][i] - newpop[j-1][i])/(bounds[i][1]-bounds[i][0])
# 选择新一代
newpop = []
for i in range(popsize):
p1 = random.randint(0, popsize-1)
p2 = random.randint(0, popsize-1)
if crowding[p1] > crowding[p2]:
newpop.append(pop[p1])
else:
newpop.append(pop[p2])
# 变异
for i in range(popsize):
if random.uniform(0,1) < 0.1:
indv = []
for j in range(len(bounds)):
indv.append(random.uniform(bounds[j][0],bounds[j][1]))
newpop[i] = indv
# 更新种群
pop = newpop
# 返回非支配解
front = []
for indv in pop:
dominated = False
for other in pop:
if indv != other and problem(indv) < problem(other):
dominated = True
break
if not dominated:
front.append(indv)
return front
# 测试
bounds = [(-5,5),(-5,5)]
front = nsga2(100, 100, bounds)
for indv in front:
print(indv, problem(indv))
```
这是一个比较简单的示例,仅用两个目标函数来演示 NSGA-II 算法的求解过程。您可以根据自己的需求修改问题定义和算法参数,来解决多目标优化问题。
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