03 聚类算法 - K-means聚类
04 聚类算法 - 代码案例一 - K-means聚类
05 聚类算法 - 二分K-Means、K-Means++、K-Means||、Canopy、Mini Batch K-Means算法

常规操作：

import time
import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
from sklearn.cluster import MiniBatchKMeans, KMeans
from sklearn.metrics.pairwise import pairwise_distances_argmin
from sklearn.datasets.samples_generator import make_blobs  ## 设置属性防止中文乱码
mpl.rcParams['font.sans-serif'] = [u'SimHei']
mpl.rcParams['axes.unicode_minus'] = False

一、初始化三个中心

centers = [[1, 1], [-1, -1], [1, -1]]
clusters = len(centers)  #聚类的数目为3    

产生3000组二维的数据，中心是意思三个中心点，标准差是0.7

X, Y = make_blobs(n_samples=3000, centers=centers, cluster_std=0.7, random_state=28)  

二、构建kmeans算法

k_means = KMeans(init='k-means++', n_clusters=clusters, random_state=28)
t0 = time.time() #当前时间
k_means.fit(X)  #训练模型
km_batch = time.time() - t0  #使用kmeans训练数据的消耗时间
print ("K-Means算法模型训练消耗时间:%.4fs" % km_batch)

K-Means算法模型训练消耗时间:0.1861s

三、构建MiniBatchKMeans算法

batch_size = 100
mbk = MiniBatchKMeans(init='k-means++', n_clusters=clusters, batch_size=batch_size, random_state=28)
t0 = time.time()
mbk.fit(X)
mbk_batch = time.time() - t0
print ("Mini Batch K-Means算法模型训练消耗时间:%.4fs" % mbk_batch)

Mini Batch K-Means算法模型训练消耗时间:0.1511s

四、预测结果

km_y_hat = k_means.predict(X)
mbkm_y_hat = mbk.predict(X)

五、获取聚类中心点并聚类中心点进行排序（方便后面画图）

#输出kmeans聚类中心点
k_means_cluster_centers = k_means.cluster_centers_#输出mbk聚类中心点
mbk_means_cluster_centers = mbk.cluster_centers_
print ("K-Means算法聚类中心点:\ncenter=", k_means_cluster_centers)
print ("Mini Batch K-Means算法聚类中心点:\ncenter=", mbk_means_cluster_centers)
order = pairwise_distances_argmin(k_means_cluster_centers,  mbk_means_cluster_centers) 

K-Means算法聚类中心点:
center= [[-1.0600799 -1.05662982]
[ 1.02975208 -1.07435837]
[ 1.01491055 1.02216649]]
Mini Batch K-Means算法聚类中心点:
center= [[ 0.99602094 1.10688195]
[-1.00828286 -1.05983915]
[ 1.07892315 -0.94286826]]

六、 画图

plt.figure(figsize=(12, 6), facecolor='w')
plt.subplots_adjust(left=0.05, right=0.95, bottom=0.05, top=0.9)
cm = mpl.colors.ListedColormap(['#FFC2CC', '#C2FFCC', '#CCC2FF'])
cm2 = mpl.colors.ListedColormap(['#FF0000', '#00FF00', '#0000FF'])

1、原始数据

plt.subplot(221)
plt.scatter(X[:, 0], X[:, 1], c=Y, s=6, cmap=cm, edgecolors='none')
plt.title(u'原始数据分布图')
plt.xticks(())
plt.yticks(())
plt.grid(True)

2、K-Means算法聚类结果图

plt.subplot(222)
plt.scatter(X[:,0], X[:,1], c=km_y_hat, s=6, cmap=cm,edgecolors='none')
plt.scatter(k_means_cluster_centers[:,0],  k_means_cluster_centers[:,1],c=range(clusters),s=60,cmap=cm2,edgecolors='none')
plt.title(u'K-Means算法聚类结果图')
plt.xticks(())
plt.yticks(())
plt.text(-3.8, 3,  'train time: %.2fms' % (km_batch*1000))
plt.grid(True)

3、Mini Batch K-Means算法聚类结果图

plt.subplot(223)
plt.scatter(X[:,0], X[:,1], c=mbkm_y_hat, s=6, cmap=cm,edgecolors='none')
plt.scatter(mbk_means_cluster_centers[:,0], mbk_means_cluster_centers[:,1],c=range(clusters),s=60,cmap=cm2,edgecolors='none')
plt.title(u'Mini Batch K-Means算法聚类结果图')
plt.xticks(())
plt.yticks(())
plt.text(-3.8, 3,  'train time: %.2fms' % (mbk_batch*1000))
plt.grid(True)

different = list(map(lambda x: (x!=0) & (x!=1) & (x!=2), mbkm_y_hat))
for k in range(clusters):  different += ((km_y_hat == k) != (mbkm_y_hat == order[k]))
identic = np.logical_not(different)
different_nodes = len(list(filter(lambda x:x, different)))

4、Mini Batch K-Means和K-Means算法预测结果不同的点

plt.subplot(224)
plt.plot(X[identic, 0], X[identic, 1], 'w', markerfacecolor='#bbbbbb', marker='.')
plt.plot(X[different, 0], X[different, 1], 'w', markerfacecolor='m', marker='.')
plt.title(u'Mini Batch K-Means和K-Means算法预测结果不同的点')
plt.xticks(())
plt.yticks(())
plt.text(-3.8, 2,  'different nodes: %d' % (different_nodes))  

plt.show()

07 聚类算法 - 代码案例三 - K-Means算法和Mini Batch K-Means算法效果评估