机器学习笔记关于python实现Kmean算法

Posted 2020-07-19 Mnster_Lu

这次是一个关于Kmean的类聚算法，

简单来说就是到中心点的距离的加权和

看起来很厉害

写出来一点不厉害

一、随机取点

import numpy as np
import cv2
from matplotlib import pyplot as plt

X = np.random.randint(25,50,(25,2))
Y = np.random.randint(60,85,(25,2))
Z = np.vstack((X,Y))

# convert to np.float32
Z = np.float32(Z)
plt.hist(Z,100,[0,100]),plt.show()

 

二、kmean部分

调用cv2库里的kmean

对A、B两类进行标记

# define criteria and apply kmeans()
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 10, 1.0)
ret,label,center=cv2.kmeans(Z,2,None,criteria,10,cv2.KMEANS_RANDOM_CENTERS)

# Now separate the data, Note the flatten()
A = Z[label.ravel()==0]
B = Z[label.ravel()==1]

 

三、类聚结果

画图画图画图

# Plot the data
plt.scatter(A[:,0],A[:,1])
plt.scatter(B[:,0],B[:,1],c = \'r\')
plt.scatter(center[:,0],center[:,1],s = 80,c = \'y\', marker = \'s\')
plt.xlabel(\'Height\'),plt.ylabel(\'Weight\')
plt.show()

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最后

代码汇总

import numpy as np
import cv2
from matplotlib import pyplot as plt

X = np.random.randint(25,50,(25,2))
Y = np.random.randint(60,85,(25,2))
Z = np.vstack((X,Y))

# convert to np.float32
Z = np.float32(Z)
plt.hist(Z,100,[0,100]),plt.show()
# define criteria and apply kmeans()
criteria = (cv2.TERM_CRITERIA_EPS + cv2.TERM_CRITERIA_MAX_ITER, 10, 1.0)
ret,label,center=cv2.kmeans(Z,2,None,criteria,10,cv2.KMEANS_RANDOM_CENTERS)

# Now separate the data, Note the flatten()
A = Z[label.ravel()==0]
B = Z[label.ravel()==1]

# Plot the data
plt.scatter(A[:,0],A[:,1])
plt.scatter(B[:,0],B[:,1],c = \'r\')
plt.scatter(center[:,0],center[:,1],s = 80,c = \'y\', marker = \'s\')
plt.xlabel(\'Height\'),plt.ylabel(\'Weight\')
plt.show()