用Python实现iris数据集使用遗传算法的KMeans聚类,并可视化,并且不使用gaft
时间: 2024-02-13 09:00:26 浏览: 148
好的,我会尽力回答您的问题。首先,我们需要导入一些必要的库,包括numpy、pandas、matplotlib和sklearn等库。具体代码如下:
```python
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from sklearn.datasets import load_iris
from sklearn.cluster import KMeans
```
接下来,我们需要加载iris数据集并进行一些预处理。代码如下:
```python
data = load_iris()
# 将数据集转换为pandas的DataFrame格式
df = pd.DataFrame(data.data, columns=data.feature_names)
# 将花的种类设置为目标变量
df['target'] = data.target
# 将目标变量转换为字符串格式
df['target'] = df['target'].apply(lambda x: data.target_names[x])
```
然后,我们需要实现遗传算法的KMeans聚类。主要步骤如下:
1. 随机生成初始种群
2. 计算每个种群的适应度值
3. 选择最佳个体
4. 进行交叉和变异操作
5. 重复步骤2-4,直到达到指定的迭代次数或达到收敛条件
具体代码如下:
```python
# 定义遗传算法的参数
POP_SIZE = 50 # 种群大小
CROSS_RATE = 0.7 # 交叉率
MUT_RATE = 0.05 # 变异率
N_GENERATIONS = 50 # 迭代次数
# 初始化种群
pop = np.random.randint(0, 3, size=(POP_SIZE, len(df)))
# 计算每个个体的适应度值
def get_fitness(pop):
fitness = []
for i in range(len(pop)):
kmeans = KMeans(n_clusters=3, init=pop[i]).fit(df.iloc[:, :-1].values)
fitness.append(-kmeans.inertia_)
return np.array(fitness)
# 选择最佳个体
def select(pop, fitness):
idx = np.random.choice(np.arange(POP_SIZE), size=POP_SIZE, replace=True,
p=fitness/fitness.sum())
return pop[idx]
# 进行交叉操作
def crossover(parents):
if np.random.rand() < CROSS_RATE:
i = np.random.randint(0, POP_SIZE, size=1)
cross_points = np.random.randint(0, 2, size=len(df)).astype(np.bool)
parents[0, cross_points] = parents[1, cross_points]
return parents
# 进行变异操作
def mutate(child):
for point in range(len(df)):
if np.random.rand() < MUT_RATE:
child[point] = np.random.randint(0, 3)
return child
# 进行遗传算法的KMeans聚类
for generation in range(N_GENERATIONS):
fitness = get_fitness(pop)
pop = select(pop, fitness)
for parent in pop:
child = crossover(parent)
child = mutate(child)
parent[:] = child
best_individual = pop[np.argmax(get_fitness(pop))]
kmeans = KMeans(n_clusters=3, init=best_individual).fit(df.iloc[:, :-1].values)
```
最后,我们可以将聚类结果可视化。代码如下:
```python
# 可视化
plt.scatter(df.iloc[:, 0], df.iloc[:, 1], c=kmeans.labels_, cmap='viridis')
centers = kmeans.cluster_centers_
plt.scatter(centers[:, 0], centers[:, 1], c='black', s=200, alpha=0.5)
plt.show()
```
这样,我们就实现了用Python实现iris数据集使用遗传算法的KMeans聚类,并可视化的功能。
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