实现聚类性能指标DI, CHI, SI 将超参数调优过程可视化:以不同的k值为横坐标,性能指标为总坐标,做出聚类模型性能曲线(2<=k<=10, 4种性能指标,4条曲线) 利用肘部法选择最佳k值 不同性能指标选出的最佳k值相同吗?
时间: 2024-03-23 15:38:45 浏览: 55
感谢您的提问。实现聚类性能指标DI, CHI, SI以及超参数调优过程可视化需要使用一些聚类算法和可视化工具,比如KMeans聚类算法和Matplotlib可视化库等。以下是具体步骤:
1. 导入必要的库和数据集:
```
import numpy as np
import pandas as pd
from sklearn.cluster import KMeans
import matplotlib.pyplot as plt
data = pd.read_csv('your_dataset.csv')
X = data.iloc[:, :-1].values
```
2. 定义聚类性能指标DI, CHI, SI:
```
def DI(X, labels):
n = len(X)
k = len(np.unique(labels))
centroids = np.array([np.mean(X[labels == i], axis=0) for i in range(k)])
variances = np.array([np.mean(np.sum((X[labels == i] - centroids[i])**2, axis=1)) for i in range(k)])
DB = np.sum([[np.sqrt(np.sum((centroids[i] - centroids[j])**2)) / np.sqrt(variances[i] + variances[j]) for j in range(k) if j != i] for i in range(k)]) / k
return DB
def CHI(X, labels):
n = len(X)
k = len(np.unique(labels))
centroids = np.array([np.mean(X[labels == i], axis=0) for i in range(k)])
variances = np.array([np.mean(np.sum((X[labels == i] - centroids[i])**2, axis=1)) for i in range(k)])
mean_var = np.mean(variances)
SW = np.sum(variances)
SB = np.sum([(np.sum((centroids[i] - np.mean(X, axis=0))**2) * np.sum(labels == i)) for i in range(k)])
CH = (SB / (k - 1)) / (SW / (n - k))
return CH
def SI(X, labels):
n = len(X)
k = len(np.unique(labels))
centroids = np.array([np.mean(X[labels == i], axis=0) for i in range(k)])
variances = np.array([np.mean(np.sum((X[labels == i] - centroids[i])**2, axis=1)) for i in range(k)])
SW = np.sum(variances)
SSB = np.sum([(np.sum((centroids[i] - np.mean(X[labels == i], axis=0))**2) * np.sum(labels == i)) for i in range(k)])
SI = (SSB / (k - 1)) / (SW / (n - k))
return SI
```
3. 定义可视化函数:
```
def visualize_performance(X):
K = range(2, 11)
DI_scores = []
CHI_scores = []
SI_scores = []
for k in K:
kmeans = KMeans(n_clusters=k, random_state=0).fit(X)
DI_scores.append(DI(X, kmeans.labels_))
CHI_scores.append(CHI(X, kmeans.labels_))
SI_scores.append(SI(X, kmeans.labels_))
plt.plot(K, DI_scores, 'r', label='DI')
plt.plot(K, CHI_scores, 'g', label='CHI')
plt.plot(K, SI_scores, 'b', label='SI')
plt.legend(loc='best')
plt.xlabel('Number of clusters')
plt.ylabel('Performance score')
plt.show()
return DI_scores, CHI_scores, SI_scores
```
4. 可视化聚类性能曲线:
```
DI_scores, CHI_scores, SI_scores = visualize_performance(X)
```
5. 利用肘部法选择最佳k值:
```
def elbow_method(scores):
deltas = np.diff(scores)
diff2 = np.diff(deltas)
elbow = np.where(diff2 > np.median(diff2))[0][0] + 2
return elbow
DI_elbow = elbow_method(DI_scores)
CHI_elbow = elbow_method(CHI_scores)
SI_elbow = elbow_method(SI_scores)
```
6. 输出不同性能指标选出的最佳k值:
```
print('The best k value for DI is', DI_elbow)
print('The best k value for CHI is', CHI_elbow)
print('The best k value for SI is', SI_elbow)
```
不同性能指标选出的最佳k值可能不同,这取决于数据集的特点和聚类算法的性能。因此,您应该根据您的实际应用选择最合适的性能指标和聚类算法。
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