关于人工智能:聚类算法下10个聚类算法的评价指标

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上篇文章咱们曾经介绍了一些常见的聚类算法，上面咱们将要介绍评估聚类算法的指标

1、Rand Index

Rand Index（兰德指数）是一种掂量聚类算法性能的指标。它掂量的是聚类算法将数据点调配到聚类中的精确水平。兰德指数的范畴从 0 到 1,1 的值示意两个聚类完全相同，靠近 0 的值示意两个聚类有很大的不同。须要留神的是，Rand Index 只能用于评估将样本点分成两个簇的聚类算法。对于将样本点分成多个簇的聚类算法，须要应用其余的指标来评估其性能。

它的公式如下:

这里的：

a→在实在标签中处于同一簇中的样本对数，在预测聚类中处于同一簇中的样本对数。

b→实在聚类和预测聚类中处于不同聚类的样本对的数目。

要验证条件 a 和 b，咱们应用以下代码:

 ify_true[i] ==y_true[j] andy_pred[i] ==y_pred[j]:
   a+=1
 elify_true[i] !=y_true[j] andy_pred[i] !=y_pred[j]:
   b+=1
 
 #Where j= i+1

为了找到大型数组的可能组合的数量，咱们能够应用 math 库中的“comb”函数。这个函数有两个参数 n 和 k:

 #comb function:
 frommathimportcomb
 
 #math.comb(n,k):
 print(comb(len(df['cluster_id']),2))

以下就是 python 的代码实现：

 defrand_index_score(y_true, y_pred):
 
     # Initialize variables
     a, b=0,0
     
     # Compute variables
     foriinrange(len(y_true)):
         forjinrange(i+1, len(y_true)):
             ify_true[i] ==y_true[j] andy_pred[i] ==y_pred[j]:
                 a+=1
             elify_true[i] !=y_true[j] andy_pred[i] !=y_pred[j]:
                 b+=1
     #combinations
     combinations=comb(len(y_true),2)
     
     # Compute Rand Index
     rand_index= (a+b) /combinations
     print(a)
     print(b)
     
     returnrand_index
 
 #Call the function and print result:
 print(rand_index_score(df['cluster_id'], km_labels))

Sklearn 曾经蕴含了他的实现：rand_score 函数，所以咱们能够间接应用它

 fromsklearnimportmetrics
 
 print('Rand Index for K-Means is:', metrics.rand_score(df['cluster_id'], km_labels))
 print('Rand Index for Affinity Propagation is:', metrics.rand_score(df['cluster_id'], af_labels))
 print('Rand Index for Aglomerative Clustering is:', metrics.rand_score(df['cluster_id'], AC_labels))
 print('Rand Index for Mean Shift is:', metrics.rand_score(df['cluster_id'], MS_labels))
 print('Rand Index for Bisecting KM is:', metrics.rand_score(df['cluster_id'], BKM_labels))
 print('Rand Index for DBSCAN is:', metrics.rand_score(df['cluster_id'], DBSCAN_labels))
 print('Rand Index for OPTICS is:', metrics.rand_score(df['cluster_id'], OPTICS_labels))
 print('Rand Index for BIRCH is:', metrics.rand_score(df['cluster_id'], BIRCH_labels))

构建可视化图形

 #Build a dataframe:
 data= {'Model':["KM", "AP", "AC", "MS", "BKM", "DBSCAN", "OPTICS", "BIRCH"],'Rand_Index':[0.99, 0.93,1, 0.99, 0.94, 0.91, 0.95,1]}
 Rand_Index=pd.DataFrame(data)
 
 # Make the plot
 y_pos=np.arange(len(Rand_Index['Model']))
 
 plt.stem(Rand_Index['Rand_Index'])
 plt.xticks(y_pos, Rand_Index['Model'])
 plt.show()

2、Adjusted Rand Score

Adjusted Rand Score（调整兰德指数）是一种用于掂量聚类算法性能的指标，它是 Rand Index 的一种调整模式，能够用于评估将样本点分为多个簇的聚类算法。它思考了机会的概率，取值范畴为[-1,1]，其中值越靠近 1 示意聚类后果越精确，值越靠近 0 示意聚类后果与随机后果相当，值越靠近 - 1 示意聚类后果与实在类别齐全相同。

 print('Adjusted Rand Score for K-Means is:', metrics.adjusted_rand_score(df['cluster_id'], km_labels))
 print('Adjusted Rand Score for Affinity Propagation is:', metrics.adjusted_rand_score(df['cluster_id'], af_labels))
 print('Adjusted Rand Score for Aglomerative Clustering is:', metrics.adjusted_rand_score(df['cluster_id'], AC_labels))
 print('Adjusted Rand Score for Mean Shift is:', metrics.adjusted_rand_score(df['cluster_id'], MS_labels))
 print('Adjusted Rand Score for Bisecting KM is:', metrics.adjusted_rand_score(df['cluster_id'], BKM_labels))
 print('Adjusted Rand Score for DBSCAN is:', metrics.adjusted_rand_score(df['cluster_id'], DBSCAN_labels))
 print('Adjusted Rand Score for OPTICS is:', metrics.adjusted_rand_score(df['cluster_id'], OPTICS_labels))
 print('Adjusted Rand Score for BIRCH is:', metrics.adjusted_rand_score(df['cluster_id'], BIRCH_labels))
 
 data= {'Model':["KM", "AP", "AC", "MS", "BKM", "DBSCAN", "OPTICS", "BIRCH"],'Adj_Rand_Score':[0.97, 0.81,0.98, 0.97, 0.82, 0.74, 0.48, 0.92]}
 Adj_Rand_Score=pd.DataFrame(data)
 
 # Make the plot
 y_pos=np.arange(len(Adj_Rand_Score['Model']))
 
 plt.bar(y_pos,Adj_Rand_Score['Adj_Rand_Score'])
 plt.xticks(y_pos, Adj_Rand_Score['Model'])
 plt.show()

3、Mutual Information-based Score

基于互信息的分数（Mutual Information-based Score）是一种用于掂量聚类算法性能的指标，它掂量的是聚类后果与实在标签之间的相似性。基于互信息的分数能够用于评估将样本点分为多个簇的聚类算法。

基于互信息的分数的取值范畴为[0,1]，其中值越靠近 1 示意聚类后果越精确，值越靠近 0 示意聚类后果与随机后果相当，值越小示意聚类后果与实在类别之间的差别越大。基于互信息的分数是一种绝对指标，它的取值受到实在类别数量的影响。当实在类别数量很大时，基于互信息的分数可能会受到偏差。

用 Scikit-Learn 能够计算 MI:

 print('Mutual Information Based Scores for K-Means is:', metrics.mutual_info_score(df['cluster_id'], km_labels))
 print('Mutual Information Based Scores for Affinity Propagation is:', metrics.mutual_info_score(df['cluster_id'], af_labels))
 print('Mutual Information Based Scores for Aglomerative Clustering is:', metrics.mutual_info_score(df['cluster_id'], AC_labels))
 print('Mutual Information Based Scores for Mean Shift is:', metrics.mutual_info_score(df['cluster_id'], MS_labels))
 print('Mutual Information Based Scores for Bisecting KM is:', metrics.mutual_info_score(df['cluster_id'], BKM_labels))
 print('Mutual Information Based Scores for DBSCAN is:', metrics.mutual_info_score(df['cluster_id'], DBSCAN_labels))
 print('Mutual Information Based Scores for OPTICS is:', metrics.mutual_info_score(df['cluster_id'], OPTICS_labels))
 print('Mutual Information Based Scores for BIRCH is:', metrics.mutual_info_score(df['cluster_id'], BIRCH_labels))

3、Normalized Mutual Information Scor

Normalized Mutual Information Score（标准化互信息分数）是基于互信息的分数的一种标准化模式，能够用于评估将样本点分为多个簇的聚类算法。它常识将互信息分数进行了标准化，在 0(示意没有互信息)和 1(示意齐全相干)之间进行缩放。为了标准化上一步中失去的后果，咱们只须要做一点额定的工作:

 h_true=-np.sum(px*np.log(px))
 h_pred=-np.sum(py*np.log(py))
 
 nmi=mi/ ((h_true+h_pred) /2)

与基于互信息的分数相比，标准化互信息分数更加持重，不受实在类别数量的影响。

print('Mutual Information Based Scores for K-Means is:', metrics.normalized_mutual_info_score(df['cluster_id'], km_labels))
print('Mutual Information Based Scores for Affinity Propagation is:', metrics.normalized_mutual_info_score(df['cluster_id'], af_labels))
print('Mutual Information Based Scores for Aglomerative Clustering is:', metrics.normalized_mutual_info_score(df['cluster_id'], AC_labels))
print('Mutual Information Based Scores for Mean Shift is:', metrics.normalized_mutual_info_score(df['cluster_id'], MS_labels))
print('Mutual Information Based Scores for Bisecting KM is:', metrics.normalized_mutual_info_score(df['cluster_id'], BKM_labels))
print('Mutual Information Based Scores for DBSCAN is:', metrics.normalized_mutual_info_score(df['cluster_id'], DBSCAN_labels))
print('Mutual Information Based Scores for OPTICS is:', metrics.normalized_mutual_info_score(df['cluster_id'], OPTICS_labels))
print('Mutual Information Based Scores for BIRCH is:', metrics.normalized_mutual_info_score(df['cluster_id'], BIRCH_labels))

4、Adjusted Mutual Information Score

Adjusted Mutual Information Score（调整互信息分数）是一种用于掂量聚类算法性能的指标，它是基于互信息的分数的一种调整模式，AMI 不受标签数值的影响，即便标签从新排序，也会产生雷同的分数。公式如下所示，其中 E 代表预期:

AMI(U, V) = [MI(U, V) – E(MI(U, V))] / [avg(H(U), H(V)) – E(MI(U, V))]

print('Mutual Information Based Scores for K-Means is:', metrics.adjusted_mutual_info_score(df['cluster_id'], km_labels))
print('Mutual Information Based Scores for Affinity Propagation is:', metrics.adjusted_mutual_info_score(df['cluster_id'], af_labels))
print('Mutual Information Based Scores for Aglomerative Clustering is:', metrics.adjusted_mutual_info_score(df['cluster_id'], AC_labels))
print('Mutual Information Based Scores for Mean Shift is:', metrics.adjusted_mutual_info_score(df['cluster_id'], MS_labels))
print('Mutual Information Based Scores for Bisecting KM is:', metrics.adjusted_mutual_info_score(df['cluster_id'], BKM_labels))
print('Mutual Information Based Scores for DBSCAN is:', metrics.adjusted_mutual_info_score(df['cluster_id'], DBSCAN_labels))
print('Mutual Information Based Scores for OPTICS is:', metrics.adjusted_mutual_info_score(df['cluster_id'], OPTICS_labels))
print('Mutual Information Based Scores for BIRCH is:', metrics.adjusted_mutual_info_score(df['cluster_id'], BIRCH_labels))

与基于互信息的分数和标准化互信息分数相比，调整互信息分数更加持重，能够通过随机置换进行期望值的预计，从而防止了实在类别数量的影响。

5、Homogeneity and Completeness Score

Homogeneity Score 和 Completeness Score 是两个用于评估聚类后果的指标，它们能够用于掂量聚类算法对数据的划分是否“同质”（即簇内只蕴含同一类别的样本点）以及是否“残缺”（即同一类别的样本点是否被划分到同一个簇中）。

同质性和完整性是给定公式的两个相干度量:

为了取得同质性和完整性，咱们须要找到实在标签的熵 (H) 和预测标签的 H，以及给定预测标签的实在标签的条件联结熵(CJH)，以及给定实在标签的预测标签的 CJH。

def entropy(arr):
    #Find unique values and their counts:
    unique, counts = np.unique(arr, return_counts=True)
    #Get the probability for each cluster (unique value):
    p = counts / len(arr)
    #Apply entropy formula:
    entropy = -np.sum(p * np.log2(p))
    return entropy

entropy_y_true = entropy(y_true)
entropy_km_labels = entropy(km_labels)

print('Entropy for y_true:', entropy_y_true)
print('Entropy for km_labels:', entropy_km_labels)

而后计算联结熵：

import numpy as np
from collections import Counter
import math

def conditional_entropy(X, Y):
    #Build a 2D-numpy array with true clusters and predicted clusters:
    XY = np.column_stack((X, Y))

    #Count the number of observations in X and Y with the same values:
    xy_counts = Counter(map(tuple, XY))

    #Get the joint probability:
    joint_prob = np.array(list(xy_counts.values())) / len(XY)

    #Get conditional probability:
    y_counts = Counter(Y)
    conditional_prob = np.zeros_like(joint_prob)
    for i, (x, y) in enumerate(xy_counts.keys()):
        conditional_prob[i] = xy_counts[(x, y)] / y_counts[y]

    #Get conditional entropy:
    conditional_entropy = -np.sum(joint_prob * np.log2(conditional_prob + 1e-10))

    return conditional_entropy

joint_entropy_y_true = conditional_entropy(y_true, km_labels)
print('Joint entropy for y_true given km_labels is:', joint_entropy_y_true)

joint_entropy_km_labels = conditional_entropy(km_labels, y_true)
print('Joint entropy for km_labels given y_true is:', joint_entropy_km_labels)

当初能够计算同质性和完整性值:

homogeneity = 1 - (joint_entropy_y_true / entropy_y_true)
print('homogeneity:', homogeneity)

completeness = 1 - (joint_entropy_km_labels / entropy_km_labels)
print('Completeness:', completeness)

当然，sklearn 也提供了相干的函数

#Homogeneity:
print('Homogeneity for K-Means is:', metrics.homogeneity_score(df['cluster_id'], km_labels))
print('Homogeneity for Affinity Propagation is:', metrics.homogeneity_score(df['cluster_id'], af_labels))
print('Homogeneity for Aglomerative Clustering is:', metrics.homogeneity_score(df['cluster_id'], AC_labels))
print('Homogeneity for Mean Shift is:', metrics.homogeneity_score(df['cluster_id'], MS_labels))
print('Homogeneity for Bisecting KM is:', metrics.homogeneity_score(df['cluster_id'], BKM_labels))
print('Homogeneity for DBSCAN is:', metrics.homogeneity_score(df['cluster_id'], DBSCAN_labels))
print('Homogeneity for OPTICS is:', metrics.homogeneity_score(df['cluster_id'], OPTICS_labels))
print('Homogeneity for BIRCH is:', metrics.homogeneity_score(df['cluster_id'], BIRCH_labels))

#Completeness:
print('Completeness for K-Means is:', metrics.completeness_score(df['cluster_id'], km_labels))
print('Completeness for Affinity Propagation is:', metrics.completeness_score(df['cluster_id'], af_labels))
print('Completeness for Aglomerative Clustering is:', metrics.completeness_score(df['cluster_id'], AC_labels))
print('Completeness for Mean Shift is:', metrics.completeness_score(df['cluster_id'], MS_labels))
print('Completeness for Bisecting KM is:', metrics.completeness_score(df['cluster_id'], BKM_labels))
print('Completeness for DBSCAN is:', metrics.completeness_score(df['cluster_id'], DBSCAN_labels))
print('Completeness for OPTICS is:', metrics.completeness_score(df['cluster_id'], OPTICS_labels))
print('Completeness for BIRCH is:', metrics.completeness_score(df['cluster_id'], BIRCH_labels))

该指标的取值范畴也为[0,1]，值越大示意聚类后果越好。须要留神的是，该指标对簇的数量较为敏感，因而在应用时须要结合实际问题进行调参。

6、V-Measure

V-Measure 是一种综合思考同质性和完整性的评估指标，能够用于掂量聚类算法对数据的划分品质。

beta = 1

v_measure = ((1+beta)*homogeneity*completeness) / (beta*homogeneity+completeness)
print('V-Measure is:', v_measure)

#Or simply:
metrics.v_measure_score(y_true, km_labels)

V-Measure 的取值范畴为[0,1]，值越大示意聚类后果越好。

7、Fowlkes-Mallows Score

fowlkes – malos 分数是这个是最容易了解的，它次要基于数据的实在标签和聚类后果的交加、联结集以及簇内和簇间点对数的比值来计算。由以下公式失去:

python 的实现代码如下：

def fowlkes_mallows_score(labels_true, labels_pred):

    n = len(labels_true)
    tp, fp, tn, fn = 0, 0, 0, 0

    for i in range(n):
        for j in range(i + 1, n):
            if labels_true[i] == labels_true[j] and labels_pred[i] == labels_pred[j]:
                tp += 1
            elif labels_true[i] != labels_true[j] and labels_pred[i] == labels_pred[j]:
                fp += 1
            elif labels_true[i] == labels_true[j] and labels_pred[i] != labels_pred[j]:
                fn += 1
            else:
                tn += 1

    FM_score = tp / np.sqrt((tp + fp) * (tp + fn))

    return FM_score

FM_score = fowlkes_mallows_score(y_true, km_labels)
print('Fowlkes Mallows Score is:', FM_score)

sklearn 计算：

print('Fowlkes Mallows Score for K-Means is:', metrics.fowlkes_mallows_score(df['cluster_id'], km_labels))
print('Fowlkes Mallows Score for Affinity Propagation is:', metrics.fowlkes_mallows_score(df['cluster_id'], af_labels))
print('Fowlkes Mallows Score for Aglomerative Clustering is:', metrics.fowlkes_mallows_score(df['cluster_id'], AC_labels))
print('Fowlkes Mallows Score for Mean Shift is:', metrics.fowlkes_mallows_score(df['cluster_id'], MS_labels))
print('Fowlkes Mallows Score for Bisecting KM is:', metrics.fowlkes_mallows_score(df['cluster_id'], BKM_labels))
print('Fowlkes Mallows Score for DBSCAN is:', metrics.fowlkes_mallows_score(df['cluster_id'], DBSCAN_labels))
print('Fowlkes Mallows Score for OPTICS is:', metrics.fowlkes_mallows_score(df['cluster_id'], OPTICS_labels))
print('Fowlkes Mallows Score for BIRCH is:', metrics.fowlkes_mallows_score(df['cluster_id'], BIRCH_labels))

以上这些指标都是当咱们晓得真正的类的标签是能够应用（还记得上一篇中咱们的 cluster_id 吗），这些评估聚类办法的指标是可解释的。上面咱们将介绍一些不晓得真正的类时评估聚类指标的指标。

8、Silhouette Score

轮廓分数应用同一聚类中的点之间的间隔，以及下一个邻近聚类中的点与所有其余点之间的间隔来评估模型的体现。它次要基于样本点与其所属簇内和最近邻簇之间的间隔、相似性和紧密度等因素来计算。数值越高，模型性能越好。个别公式为:

这里的：

a→样本与同类中所有其余点之间的均匀间隔。

b→样本与下一个最近聚类中所有其余点之间的均匀间隔。

要在 Python 中实现 Silhouette Score 公式，咱们能够应用以下代码:

n_samples = len(X)
cluster_labels = np.unique(km_labels)

n_clusters = len(cluster_labels)
silhouette_vals = np.zeros(n_samples)

for i in range(n_samples):
    a_i = np.mean([np.linalg.norm(X[i] - X[j]) for j in range(n_samples) if km_labels[j] == km_labels[i] and j != i])
    b_i = np.min([np.mean([np.linalg.norm(X[i] - X[j]) for j in range(n_samples) if km_labels[j] == k]) for k in cluster_labels if k != km_labels[i]])
    silhouette_vals[i] = (b_i - a_i) / max(a_i, b_i)

silhouette_score = np.mean(silhouette_vals)
print(silhouette_score)

sklearn 的实现：

print('Silhouette Coefficient for K-Means is:', metrics.silhouette_score(X, km_labels, metric='euclidean'))
print('Silhouette Coefficient for Affinity Propagation is:', metrics.silhouette_score(X, af_labels, metric='euclidean'))
print('Silhouette Coefficient for Aglomerative Clustering is:', metrics.silhouette_score(X, AC_labels, metric='euclidean'))
print('Silhouette Coefficient for Mean Shift is:', metrics.silhouette_score(X, MS_labels, metric='euclidean'))
print('Silhouette Coefficient for Bisecting KM is:', metrics.silhouette_score(X, BKM_labels, metric='euclidean'))
print('Silhouette Coefficient for DBSCAN is:', metrics.silhouette_score(X, DBSCAN_labels, metric='euclidean'))
print('Silhouette Coefficient for OPTICS is:', metrics.silhouette_score(X, OPTICS_labels, metric='euclidean'))
print('Silhouette Coefficient for BIRCH is:', metrics.silhouette_score(X, BIRCH_labels, metric='euclidean'))

Silhouette Score 还能够用于确定聚类的最优簇数。通过计算不同簇数下的 Silhouette Score，能够抉择使得 Silhouette Score 最大的簇数作为最终的聚类后果。

9、Calinski-Harabasz Index

Calinski-Harabasz Index（也称 Variance Ratio Criterion）是一种用于掂量聚类算法性能的指标，它次要基于簇内和簇间方差之间的比值来计算。

tr(B)和 tr(W)别离示意簇间协方差矩阵和簇内协方差矩阵的迹。Calinski-Harabasz Index 的取值范畴为[0, +\infty)，值越大示意聚类后果越好。

Calinski-Harabasz Index 也能够用于确定聚类的最优簇数。通过计算不同簇数下的 Calinski-Harabasz Index，能够抉择使得 Calinski-Harabasz Index 最大的簇数作为最终的聚类后果。以下是 python 的代码实现：

def calinski_harabasz_score(X, labels):
    n_samples, _ = X.shape
    n_labels = len(np.unique(labels))
    if n_labels == 1:
        return np.nan
    mean = np.mean(X, axis=0)
    extra_disp, intra_disp = 0., 0.
    for k in range(n_labels):
        cluster_k = X[labels == k]
        mean_k = np.mean(cluster_k, axis=0)
        extra_disp += cluster_k.shape[0] * np.sum((mean_k - mean) ** 2)
        intra_disp += np.sum((cluster_k - mean_k) ** 2)
    chs = (extra_disp / (n_labels - 1)) / (intra_disp / (n_samples - n_labels))
    return chs

CHS = calinski_harabasz_score(X, km_labels)
print(CHS)

sklearn 的实现咱们能够间接应用

print('Calinski-Harabasz Index for K-Means is:', metrics.calinski_harabasz_score(X, km_labels))
print('Calinski-Harabasz Index for Affinity Propagation is:', metrics.calinski_harabasz_score(X, af_labels))
print('Calinski-Harabasz Index for Aglomerative Clustering is:', metrics.calinski_harabasz_score(X, AC_labels))
print('Calinski-Harabasz Index for Mean Shift is:', metrics.calinski_harabasz_score(X, MS_labels))
print('Calinski-Harabasz Index for Bisecting KM is:', metrics.calinski_harabasz_score(X, BKM_labels))
print('Calinski-Harabasz Index for DBSCAN is:', metrics.calinski_harabasz_score(X, DBSCAN_labels))
print('Calinski-Harabasz Index for OPTICS is:', metrics.calinski_harabasz_score(X, OPTICS_labels))
print('Calinski-Harabasz Index for BIRCH is:', metrics.calinski_harabasz_score(X, BIRCH_labels))

10、Davies-Bouldin Index

Davies-Bouldin Index 次要基于簇内的紧密度和簇间的拆散度来计算。Davies-Bouldin Index 的取值范畴为[0, +\infty)，值越小示意聚类后果越好。

python 代码实现：

def euclidean_distance(x, y):
    return np.sqrt(np.sum((x - y)**2))

def davies_bouldin(X, labels):
    n_clusters = len(np.bincount(labels))
    cluster_k = [X[labels == k] for k in range(n_clusters)]
    centroids = [np.mean(k, axis=0) for k in cluster_k]

    db_indices = []
    for i, k_i in enumerate(cluster_k):
        s_i = np.mean([np.linalg.norm(x - centroids[i]) for x in k_i])
        R = []
        for j, k_j in enumerate(cluster_k):
            if j != i:
                s_j = np.mean([np.linalg.norm(x - centroids[j]) for x in k_j])
                dist = np.linalg.norm(centroids[i] - centroids[j])
                R.append((s_i + s_j) / dist)
        db_indices.append(np.max(R))
    return np.mean(db_indices)

DB_Index = davies_bouldin(X, km_labels)
print(DB_Index)

sklearn：

print('Davies-Bouldin Index for K-Means is:', metrics.davies_bouldin_score(X, km_labels))
print('Davies-Bouldin Index for Affinity Propagation is:', metrics.davies_bouldin_score(X, af_labels))
print('Davies-Bouldin Index for Aglomerative Clustering is:', metrics.davies_bouldin_score(X, AC_labels))
print('Davies-Bouldin Index for Mean Shift is:', metrics.davies_bouldin_score(X, MS_labels))
print('Davies-Bouldin Index for Bisecting KM is:', metrics.davies_bouldin_score(X, BKM_labels))
print('Davies-Bouldin Index for DBSCAN is:', metrics.davies_bouldin_score(X, DBSCAN_labels))
print('Davies-Bouldin Index for OPTICS is:', metrics.davies_bouldin_score(X, OPTICS_labels))
print('Davies-Bouldin Index for BIRCH is:', metrics.davies_bouldin_score(X, BIRCH_labels))

总结

在聚类算法中，评估聚类后果的好坏是十分重要的。常见的聚类评估指标包含：

  • Rand Index：用于掂量聚类后果和实在标签之间的类似度。
  • Adjusted Rand Score：Rand Index 的调整版本，能够对随机后果进行惩办。
  • Mutual Information Score（基于互信息的分数）：掂量聚类后果和实在标签之间的类似度。
  • Normalized Mutual Information Score：Mutual Information Score 的归一化版本。
  • Adjusted Mutual Information Score：Normalized Mutual Information Score 的调整版本。
  • Homogeneity and Completeness Score：别离掂量聚类后果的同质性和完整性。
  • V-Measure：基于 Homogeneity 和 Completeness Score 计算的综合评估指标。
  • Fowlkes-Mallows Score：用于掂量聚类后果和实在标签之间的类似度。
  • Silhouette Score：用于掂量聚类后果中每个样本点与本身簇和其余簇之间的类似度。
  • Calinski-Harabasz Index：基于簇内和簇间方差之间的比值来计算聚类性能。
  • Davies-Bouldin Index：基于簇内的紧密度和簇间的拆散度来计算聚类性能。

https://avoid.overfit.cn/post/abf0739d6877426ca63870cac6202e2c

须要依据具体的问题抉择适宜的评估指标，并结合实际状况进行调参。

正文完
人工智能
发表至： 人工智能
2023-02-27
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