我正在实现一种算法来解决8皇后问题：https://en.wikipedia.org/wiki/Eight_queens_puzzle
在尝试遍历整个种群并通过一些交叉创建一个新种群时，我遇到了一个问题。问题出在numpy.random的选择函数中。
我的意图是将population分配给newPopulation（第50行），空的newPopulation（第53行），然后下一次迭代将新的100个子代追加到{{1} }。
有人抱怨输入到choice（）的列表大小不一样，即使我在循环之前打印了每一个的len（）并且显示它们都是100？
完整错误：
newPopulation这是我的程序：
Traceback (most recent call last):
File "test.py", line 44, in <module>
choice1 = choice(population, p=normalFitness)
File "mtrand.pyx", line 1141, in mtrand.RandomState.choice
ValueError: 'a' and 'p' must have same size
我认为可能是因为我将normalFitness列表分配给了一个空列表，而不是使用了del。如果我将第53行更改为： 1 import queensState as qs
2 import numpy as np
3 import random
4 from numpy.random import choice
5
6 def cross(state1,state2):
7 return qs.State([state1.state[0],state1.state[1],state1.state[2],state1.state[3],state2.state[4], state2.state[5],state2.state[6],state2.state[7]])
8
9 #create the initial population
10 population = []
11 newPopulation = []
12 normalFitness = []
13 fitness=np.zeros((100,),dtype=int)
14
15 #step through each state and give
16 #random values to each index in the array
17 for i in range(100):
18 x = []
19 for h in range(8):
20 d = random.randint(1,8)
21 x.append(d)
22 newState = qs.State(x)
23 #append the current state to the population with
24 #the fitness(hash) and the state array
25 population.append(newState)
26
27
28 for i in range(100):
29 totalFitness = 0
30 for n in range(100): #calculate total fitness
31 totalFitness+=population[n].fitness
32
33 fitness[i]=totalFitness
34
35 #initialize the normalized fitness array
36 for x in range(100):
37 normalFitness.append(population[x].fitness/totalFitness)
38
39 print("poplen: ",len(population)," fitlen: ",len(normalFitness)) #this prints "poplen: 100 fitlen: 100"
40 for x in range(100): #this loop is solely for testing
41 print("Pop: ",population[x].state," normalfit: ", normalFitness[x])
42
43 for x in range(100):
44 choice1 = choice(population, p=normalFitness)
45 choice2 = choice(population, p=normalFitness)
46 child = cross(choice1,choice2)
47 newPopulation.append(child)
48 #print("State1: ", choice1.state, " State2: ",choice2.state, "Cross: ", child.state)
49
50 population = newPopulation
51 for x in range(100):
52 print(population[x].state)
53 normalFitness=[]
54 print(len(normalFitness))
55
56 print(fitness)
，则它具有相同的行为。
如果需要，这里是QueensState代码：
del normalFitness[:]任何想法都将不胜感激！
谢谢。