python实现agnes算法计算轮廓系数
时间: 2023-08-16 22:10:32 浏览: 39
好的,下面是Python实现AGNES算法计算轮廓系数的代码:
```python
import numpy as np
from sklearn.metrics import silhouette_score
# 距离矩阵
def distance_matrix(X):
n = X.shape[0]
dist_matrix = np.zeros((n, n))
for i in range(n):
for j in range(i+1, n):
dist_matrix[i][j] = dist_matrix[j][i] = np.linalg.norm(X[i]-X[j])
return dist_matrix
# AGNES聚类
def AGNES(X, k):
n = X.shape[0]
# 初始化每个点为一类
clusters = [[i] for i in range(n)]
# 计算距离矩阵
dist_matrix = distance_matrix(X)
# 合并聚类
while len(clusters) > k:
min_dist = np.inf
merge_i, merge_j = -1, -1
for i in range(len(clusters)):
for j in range(i+1, len(clusters)):
dist = 0
for m in clusters[i]:
for n in clusters[j]:
dist += dist_matrix[m][n]
dist /= len(clusters[i]) * len(clusters[j])
if dist < min_dist:
min_dist = dist
merge_i, merge_j = i, j
clusters[merge_i].extend(clusters[merge_j])
del clusters[merge_j]
return clusters
# 计算轮廓系数
def silhouette_coefficient(X, clusters):
labels = np.zeros(X.shape[0])
k = len(clusters)
for i in range(k):
for j in clusters[i]:
labels[j] = i
return silhouette_score(X, labels)
# 测试
if __name__ == '__main__':
X = np.array([[2, 10], [2, 5], [8, 4], [5, 8], [7, 5], [6, 4], [1, 2], [4, 9]])
k = 3
clusters = AGNES(X, k)
sc = silhouette_coefficient(X, clusters)
print('聚%d类的轮廓系数为:%f' % (k, sc))
```
这段代码中,`distance_matrix`函数用于计算距离矩阵,`AGNES`函数实现了AGNES聚类算法,`silhouette_coefficient`函数用于计算轮廓系数。在测试部分,我们可以设定聚类数`k`为3,然后计算轮廓系数。
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