《机器学习实战》支持向量机（手稿+代码）

注释：已经看过有半年了，而且当时只是看了理论和opencv的函数调用，现在忘的九霄云外了，Ng的视频也没看SVM，现在准备系统的再学一遍吧。

之前记录的博客：http://www.cnblogs.com/wjy-lulu/p/6979436.html

一.SVM理论重点和难点剖析

　　注释：这里主要讲解公式推导和证明的重难点，不是按部就班的讲解SVM的求解过程，算是对推导过程的补充吧！

　　　　　一点未接触过SVM的请看大神的博客：

　　　　　　　　　　　　　　　　　　　　http://blog.csdn.net/c406495762/article/details/78072313

　　　　　　　　　　　　　　　　　　　　http://www.cnblogs.com/jerrylead/archive/2011/03/13/1982684.html

　　　　　　　　　　　　　　　　　　　　http://blog.csdn.net/zouxy09/article/details/17291543

　　　　　　　　　　　　　　　　　　　　http://blog.pluskid.org/?p=685

　　　　　　　　　　　　　　　　　　　　http://blog.csdn.net/v_july_v/article/details/7624837

　　1.1点到直线距离的由来

　　　　我们先讨论点到平面的距离，由此推广到点到直线和点到超平面的距离公式。　　　　

点到平面公式推导

SVM公式推导一

SVM公式推导二

　　1.2拉格朗日对偶问题

　　　　用于求解带条件的最优化问题，其实到最后你就明白了SVM从头到尾最主要做的就是如何高效的求解目标值。而其它的学习算法做的都是对数据的求解优化问题，这点是SVM和其它算法根本的区别。

原始问题

对偶问题一

对偶问题2

原始问题和对偶问题的关系

KKT条件

SVM公式推导三

SVM公式推导四

　　1.3核函数的推导

　　　　目的：1.处理线性不可分的情况。2.求解方便。

　　　　过程：二维情况的不可分割，就映射到三维、四维....等高维空间去分割。

　　　　通俗解释：https://www.zhihu.com/question/24627666 知乎大神开始装逼的时刻了。

　　　　理论部分：如下公式推导.......

核函数引出一

　　1.4松弛变量的引入

　　　　目的：防止部分异常点的干扰。

　　　　原理：和其它算法引入惩罚系数一样的，允许有异常点但是要接受惩罚。比如：异常的点肯定都是偏离群体的点，既然偏离群体，那么它的值就为负数且绝对值愈大惩罚程度越大。

　　　　具体推导：见下文......

松弛变量的引入

　　1.5.SMO算法

SMO算法一

SMO算法二

　　　　注释：后面还有参数如何最优选择，有点看不懂而且也有点不想看了，干脆从下面的代码去分析SMO的具体过程吧！

二.程序实现

　代码实现强烈推荐：http://blog.csdn.net/c406495762/article/details/78072313

　　给了程序伪代码很详细，程序读起来很方便。

　　2.1.SMO实现

　　　　2.1.1简化版SMO

　　　　简化版：针对理论中“SMO”的最后一句话，最优选择的问题！简化版是随机选择，选择上不做优化。

 1 import numpy as np
 2 import matplotlib.pyplot as plt
 3 
 4 #预处理数据
 5 def loadDataSet(fileName):
 6     dataMat  = []
 7     labelMat = []
 8     fr = open(fileName,'r')
 9     for line in fr.readlines():
10         lineArr = line.strip().split('\t')
11         dataMat.append([float(lineArr[0]),float(lineArr[1])])
12         labelMat.append(float(lineArr[2]))
13     a = np.mat(dataMat)
14     b = np.mat(labelMat).transpose()
15     DataLabel = np.array(np.hstack((a,b)))
16     return dataMat, labelMat, DataLabel
17 #随机
18 def selectJrand(i,m):
19     j = i
20     while(j==i):
21         j = int(np.random.uniform(0,m))
22     return j
23 #约束之后的aj
24 def clipAlpha(aj,H,L):
25     if aj>H:
26         aj = H
27     elif aj<L:
28         aj = L
29     return aj
30 #C:松弛系数
31 #maxIter:迭代次数
32 def smoSimple(dataMatIn,classLabels,C,toler,maxIter):
33     dataMatraix  = np.mat(dataMatIn)
34     labelMatraix = np.mat(classLabels).transpose()
35     b =0
36     m,n = dataMatraix.shape
37     alphas = np.mat(np.zeros((m,1)))#系数都初始化为0
38     iter = 0
39     while(iter<maxIter):#大循环是最大迭代次数
40         alphaPairsChange = 0
41         for i in range(m):#样本训练
42             #预测值,具体看博客手写图片
43             fXi = float(np.multiply(alphas,labelMatraix).T*(dataMatraix*dataMatraix[i,:].T))+b
44             #误差
45             Ei  = fXi - float(labelMatraix[i])
46             #满足条件才能更新a,b的值,感觉这里的labelMat[i]不影响结果
47             if(((labelMatraix[i]*Ei<-toler) and (alphas[i]<C))\
48                 or ((labelMatraix[i]*Ei)>toler) and (alphas[i]>0)):
49                 j = selectJrand(i,m)#随机选择一个不同于i的[0,m]
50                 fXj = float(np.multiply(alphas,labelMatraix).transpose()\
51                             *(dataMatraix*dataMatraix[j,:].T))+b
52                 Ej  = fXj - float(labelMatraix[j])
53                 alphaIold = alphas[i].copy()
54                 alphaJold = alphas[j].copy()
55                 if (labelMatraix[i] != labelMatraix[j]):
56                     L = max(0,alphas[j]-alphas[i])
57                     H = min(C,C+alphas[j]-alphas[i])
58                 else:
59                     L = max(0,alphas[i]+alphas[j]-C)
60                     H = min(C,alphas[i]+alphas[j])
61                 if (L==H):
62                     print('L==H')
63                     continue
64                 #计算
65                 eta = 2.0*dataMatraix[i,:]*dataMatraix[j,:].T\
66                         - dataMatraix[i,:]*dataMatraix[i,:].T\
67                         - dataMatraix[j,:]*dataMatraix[j,:].T
68                 if (eta>0):
69                     print("eta>0")
70                     continue
71                 #更新a的新值j
72                 alphas[j] -= labelMatraix[j]*(Ei - Ej)/eta
73                 #修剪aj
74                 alphas[j] = clipAlpha(alphas[j],H,L)
75                 if (abs(alphas[j] - alphaJold) < 0.00001):
76                     print("aj not moving")
77                 #更新ai
78                 alphas[i] += labelMatraix[j]*labelMatraix[i]*(alphaJold - alphas[j])
79                 #更新b1,b2
80                 b1 = b - Ei - labelMatraix[i]*(alphas[i]-alphaIold)*dataMatraix[i,:]\
81                               *dataMatraix[i,:].T - labelMatraix[j]*(alphas[j]-alphaJold)*dataMatraix[i,:]*dataMatraix[j,:].T
82                 b2 = b - Ej - labelMatraix[i]*(alphas[i] - alphaIold)*dataMatraix[i,:]\
83                               * dataMatraix[j, :].T - labelMatraix[j]*(alphas[j] - alphaJold) * dataMatraix[j,:] * dataMatraix[j,:].T
84                 #通过b1和b2计算b
85                 if (0< alphas[i] <C): b = b1
86                 elif (0<alphas[j]<C): b = b2
87                 else: b = (b1+b2)/2
88                 #计算更新次数,用来判断是否训练数据是否全部达标
89                 alphaPairsChange += 1
90                 print("iter: %d i:%d pairs:%d "%(iter,i,alphaPairsChange))
91         #连续的达标次数
92         if(alphaPairsChange==0): iter +=1
93         else: iter = 0
94         print("iteration number: %d"%(iter))
95     return b, alphas

　　　　2.1.2效果图

main.py文件

 1 import svm
 2 import matplotlib.pyplot as plt
 3 import numpy as np
 4 
 5 if __name__ == '__main__':
 6     fig = plt.figure()
 7     axis = fig.add_subplot(111)
 8     dataMat, labelMat,DataLabel= svm.loadDataSet("testSet.txt")
 9     #b, alphas = svm.smoSimple(dataMat,labelMat,0.6,0.001,40)
10     #ws = svm.calsWs(alphas,dataMat,labelMat)
11     pData0 = [0,0,0]
12     pData1 = [0,0,0]
13     for hLData in DataLabel:
14         if (hLData[-1]==1):pData0 = np.vstack((pData0,hLData))
15         elif(hLData[-1]==-1):pData1 = np.vstack((pData1,hLData))
16         else:continue
17     vmax = np.max(pData0[:,0:1])
18     vmin = np.min(pData0[:,0:1])
19     axis.scatter(pData0[:,0:1],pData0[:,1:2],marker = 'v')
20     axis.scatter(pData1[:,0:1],pData1[:,1:2],marker = 's')
21     xdata = np.random.uniform(2.0,8.0,[1,20])
22     ydata = xdata*(0.81445/0.27279) - (3.837/0.27279)
23     axis.plot(xdata.tolist()[0],ydata.tolist()[0],'r')
24     
25     fig.show()
26     
27     #print("alphas = ",alphas[alphas>0])

View Code

svm.py文件

  1 import numpy as np
  2 import matplotlib.pyplot as plt
  3 
  4 #预处理数据
  5 def loadDataSet(fileName):
  6     dataMat  = []
  7     labelMat = []
  8     fr = open(fileName,'r')
  9     for line in fr.readlines():
 10         lineArr = line.strip().split('\t')
 11         dataMat.append([float(lineArr[0]),float(lineArr[1])])
 12         labelMat.append(float(lineArr[2]))
 13     a = np.mat(dataMat)
 14     b = np.mat(labelMat).transpose()
 15     DataLabel = np.array(np.hstack((a,b)))
 16     return dataMat, labelMat, DataLabel
 17 #随机
 18 def selectJrand(i,m):
 19     j = i
 20     while(j==i):
 21         j = int(np.random.uniform(0,m))
 22     return j
 23 #约束之后的aj
 24 def clipAlpha(aj,H,L):
 25     if aj>H:
 26         aj = H
 27     elif aj<L:
 28         aj = L
 29     return aj
 30 #C:松弛系数
 31 #maxIter:迭代次数
 32 def smoSimple(dataMatIn,classLabels,C,toler,maxIter):
 33     dataMatraix  = np.mat(dataMatIn)
 34     labelMatraix = np.mat(classLabels).transpose()
 35     b =0
 36     m,n = dataMatraix.shape
 37     alphas = np.mat(np.zeros((m,1)))#系数都初始化为0
 38     iter = 0
 39     while(iter<maxIter):#大循环是最大迭代次数
 40         alphaPairsChange = 0
 41         for i in range(m):#样本训练
 42             #预测值,具体看博客手写图片
 43             fXi = float(np.multiply(alphas,labelMatraix).T*(dataMatraix*dataMatraix[i,:].T))+b
 44             #误差
 45             Ei  = fXi - float(labelMatraix[i])
 46             #满足条件才能更新a,b的值,感觉这里的labelMat[i]不影响结果
 47             if(((labelMatraix[i]*Ei<-toler) and (alphas[i]<C))\
 48                 or ((labelMatraix[i]*Ei)>toler) and (alphas[i]>0)):
 49                 j = selectJrand(i,m)#随机选择一个不同于i的[0,m]
 50                 fXj = float(np.multiply(alphas,labelMatraix).transpose()\
 51                             *(dataMatraix*dataMatraix[j,:].T))+b
 52                 Ej  = fXj - float(labelMatraix[j])
 53                 alphaIold = alphas[i].copy()
 54                 alphaJold = alphas[j].copy()
 55                 if (labelMatraix[i] != labelMatraix[j]):
 56                     L = max(0,alphas[j]-alphas[i])
 57                     H = min(C,C+alphas[j]-alphas[i])
 58                 else:
 59                     L = max(0,alphas[i]+alphas[j]-C)
 60                     H = min(C,alphas[i]+alphas[j])
 61                 if (L==H):
 62                     print('L==H')
 63                     continue
 64                 #计算
 65                 eta = 2.0*dataMatraix[i,:]*dataMatraix[j,:].T\
 66                         - dataMatraix[i,:]*dataMatraix[i,:].T\
 67                         - dataMatraix[j,:]*dataMatraix[j,:].T
 68                 if (eta>0):
 69                     print("eta>0")
 70                     continue
 71                 #更新a的新值j
 72                 alphas[j] -= labelMatraix[j]*(Ei - Ej)/eta
 73                 #修剪aj
 74                 alphas[j] = clipAlpha(alphas[j],H,L)
 75                 if (abs(alphas[j] - alphaJold) < 0.00001):
 76                     print("aj not moving")
 77                 #更新ai
 78                 alphas[i] += labelMatraix[j]*labelMatraix[i]*(alphaJold - alphas[j])
 79                 #更新b1,b2
 80                 b1 = b - Ei - labelMatraix[i]*(alphas[i]-alphaIold)*dataMatraix[i,:]\
 81                               *dataMatraix[i,:].T - labelMatraix[j]*(alphas[j]-alphaJold)*dataMatraix[i,:]*dataMatraix[j,:].T
 82                 b2 = b - Ej - labelMatraix[i]*(alphas[i] - alphaIold)*dataMatraix[i,:]\
 83                               * dataMatraix[j, :].T - labelMatraix[j]*(alphas[j] - alphaJold) * dataMatraix[j,:] * dataMatraix[j,:].T
 84                 #通过b1和b2计算b
 85                 if (0< alphas[i] <C): b = b1
 86                 elif (0<alphas[j]<C): b = b2
 87                 else: b = (b1+b2)/2
 88                 #计算更新次数,用来判断是否训练数据是否全部达标
 89                 alphaPairsChange += 1
 90                 print("iter: %d i:%d pairs:%d "%(iter,i,alphaPairsChange))
 91         #连续的达标次数
 92         if(alphaPairsChange==0): iter +=1
 93         else: iter = 0
 94         print("iteration number: %d"%(iter))
 95     return b, alphas
 96 
 97 #分类函数
 98 def calsWs(alphas,dataArr,classLabels):
 99     X = np.mat(dataArr)
100     labelMat = np.mat(classLabels).T
101     alphas = np.mat(np.array(alphas).reshape((1,100))).T
102     m, n = X.shape
103     w = np.zeros([n,1])
104     for i in range(m):
105         w += np.multiply(alphas[i]*labelMat[i],X[i,:].T)
106     return w

View Code

　　　　2.1.3非线性分类（核向量）

　　程序代码：

  1 import numpy as np
  2 import matplotlib.pyplot as plt
  3 
  4 #预处理数据
  5 def loadDataSet(fileName):
  6     dataMat  = []
  7     labelMat = []
  8     fr = open(fileName,'r')
  9     for line in fr.readlines():
 10         lineArr = line.strip().split('\t')
 11         dataMat.append([float(lineArr[0]),float(lineArr[1])])
 12         labelMat.append(float(lineArr[2]))
 13     a = np.mat(dataMat)
 14     b = np.mat(labelMat).T
 15     DataLabel = np.array(np.hstack((a,b)))
 16     return dataMat, labelMat, DataLabel
 17 #随机
 18 def selectJrand(i,m):
 19     j = i
 20     while(j==i):
 21         j = int(np.random.uniform(0,m))
 22     return j
 23 #约束之后的aj
 24 def clipAlpha(aj,H,L):
 25     if aj>H:
 26         aj = H
 27     elif aj<L:
 28         aj = L
 29     return aj
 30 #C:松弛系数
 31 #maxIter:迭代次数
 32 def smselfimple(dataMatIn,classLabels,C,toler,maxIter):
 33     dataMatraix  = np.mat(dataMatIn)
 34     labelMatraix = np.mat(classLabels).transpselfe()
 35     b =0
 36     m,n = dataMatraix.shape
 37     alphas = np.mat(np.zerself((m,1)))#系数都初始化为0
 38     iter = 0
 39     while(iter<maxIter):#大循环是最大迭代次数
 40         alphaPairsChange = 0
 41         for i in range(m):#样本训练
 42             #预测值,具体看博客手写图片
 43             fXi = float(np.multiply(alphas,labelMatraix).T*(dataMatraix*dataMatraix[i,:].T))+b
 44             #误差
 45             Ei  = fXi - float(labelMatraix[i])
 46             #满足条件才能更新a,b的值,感觉这里的labelMat[i]不影响结果
 47             if(((labelMatraix[i]*Ei<-toler) and (alphas[i]<C))\
 48                 or ((labelMatraix[i]*Ei)>toler) and (alphas[i]>0)):
 49                 j = selectJrand(i,m)#随机选择一个不同于i的[0,m]
 50                 fXj = float(np.multiply(alphas,labelMatraix).transpselfe()\
 51                             *(dataMatraix*dataMatraix[j,:].T))+b
 52                 Ej  = fXj - float(labelMatraix[j])
 53                 alphaIold = alphas[i].copy()
 54                 alphaJold = alphas[j].copy()
 55                 if (labelMatraix[i] != labelMatraix[j]):
 56                     L = max(0,alphas[j]-alphas[i])
 57                     H = min(C,C+alphas[j]-alphas[i])
 58                 else:
 59                     L = max(0,alphas[i]+alphas[j]-C)
 60                     H = min(C,alphas[i]+alphas[j])
 61                 if (L==H):
 62                     print('L==H')
 63                     continue
 64                 #计算
 65                 eta = 2.0*dataMatraix[i,:]*dataMatraix[j,:].T\
 66                         - dataMatraix[i,:]*dataMatraix[i,:].T\
 67                         - dataMatraix[j,:]*dataMatraix[j,:].T
 68                 if (eta>0):
 69                     print("eta>0")
 70                     continue
 71                 #更新a的新值j
 72                 alphas[j] -= labelMatraix[j]*(Ei - Ej)/eta
 73                 #修剪aj
 74                 alphas[j] = clipAlpha(alphas[j],H,L)
 75                 if (abs(alphas[j] - alphaJold) < 0.00001):
 76                     print("aj not moving")
 77                 #更新ai
 78                 alphas[i] += labelMatraix[j]*labelMatraix[i]*(alphaJold - alphas[j])
 79                 #更新b1,b2
 80                 b1 = b - Ei - labelMatraix[i]*(alphas[i]-alphaIold)*dataMatraix[i,:]\
 81                               *dataMatraix[i,:].T - labelMatraix[j]*(alphas[j]-alphaJold)*dataMatraix[i,:]*dataMatraix[j,:].T
 82                 b2 = b - Ej - labelMatraix[i]*(alphas[i] - alphaIold)*dataMatraix[i,:]\
 83                               * dataMatraix[j, :].T - labelMatraix[j]*(alphas[j] - alphaJold) * dataMatraix[j,:] * dataMatraix[j,:].T
 84                 #通过b1和b2计算b
 85                 if (0< alphas[i] <C): b = b1
 86                 elif (0<alphas[j]<C): b = b2
 87                 else: b = (b1+b2)/2
 88                 #计算更新次数,用来判断是否训练数据是否全部达标
 89                 alphaPairsChange += 1
 90                 print("iter: %d i:%d pairs:%d "%(iter,i,alphaPairsChange))
 91         #连续的达标次数
 92         if(alphaPairsChange==0): iter +=1
 93         else: iter = 0
 94         print("iteration number: %d"%(iter))
 95     return b, alphas
 96 
 97 #分类函数
 98 def calsWs(alphas,dataArr,classLabels):
 99     X = np.mat(dataArr)
100     labelMat = np.mat(classLabels).T
101     alphas = np.mat(np.array(alphas).reshape((1,100))).T
102     w = np.sum(np.multiply(np.multiply(alphas,labelMat),X),axis=0)
103     return w
104 
105 #完整版SMO
106 class optStruct:
107     def __init__(self,dataMatIn,classLabel,C,toler,kTup):
108         self.X = dataMatIn
109         self.labelMat = classLabel
110         self.C = C
111         self.tol = toler
112         self.m = np.shape(dataMatIn)[0]
113         self.alphas = np.mat(np.zeros((self.m,1)))
114         self.b = 0
115         self.eCache = np.mat(np.zeros((self.m,2)))#存储误差,用于启发式搜索
116         self.K = np.mat(np.zeros((self.m,self.m)))#存储核函数转化后的dataMatIn
117         for i in range(self.m):
118             self.K[:,i] = kernelTrans(self.X,self.X[i,:],kTup)
119     def clacEk(self,k):
120         #计算当前值
121         fXk = float(np.multiply(self.alphas,self.labelMat).T*self.K[:,k]+ self.b)
122         Ek  = fXk - float(self.labelMat[k])
123         return Ek
124     def selecJ(self,i,Ei):
125         maxK = -1
126         maxDeltaE = 0
127         Ej = 0
128         self.eCache[i] = [1,Ei]#存储偏差
129         #A代表mat转换成array类型,nonzero返回非零元素的下标
130         validEcacheList = np.nonzero(self.eCache[:,0].A)[0]
131         if (len(validEcacheList)>1):#启发式选择
132             for k in validEcacheList:
133                 if (k==i):continue#k不能等于i
134                 Ek = self.clacEk(k)#计算绝对偏差
135                 deltaE = abs(Ei - Ek)#相对偏差
136                 if (deltaE >maxDeltaE):
137                     maxK = k
138                     maxDeltaE = deltaE
139                     Ej = Ek
140             return maxK, Ej
141 
142         else:
143             j = selectJrand(i,self.m)#随机选择
144             Ej = self.clacEk(j)#随机绝对偏差
145         return j,Ej
146     def updataEk(self,k):
147         Ek = self.clacEk(k)
148         self.eCache[k] = [k,Ek]
149     def innerL(self,i):
150         Ei = self.clacEk(i)
151         if ((self.labelMat[i]*Ei<-self.tol and self.alphas[i]<self.C)\
152                     or(self.labelMat[i]*Ei>self.tol and self.alphas[i]>0)):
153             j,Ej = self.selecJ(i,Ei)#选择J
154             alphaIold = self.alphas[i].copy()
155             alphaJold = self.alphas[j].copy()
156             #计算L和H的值
157             if (self.labelMat[i] != self.labelMat[j]):
158                 L = max(0,self.alphas[j]-self.alphas[i])
159                 H = min(self.C,self.C+self.alphas[j]-self.alphas[i])
160             else:
161                 L = max(0,self.alphas[j]+self.alphas[i]-self.C)
162                 H = min(self.C,self.alphas[i] +self.alphas[j])
163             if (L==H): return 0
164             #eta = 2.0* self.X[i,:]*self.X[j,:].T - self.X[i,:]*self.X[i,:].T - \
165             #    self.X[j,:]*self.X[j,:].T
166             eta = 2.0*self.K[i,j] - self.K[i,i] - self.K[j,j]#在此应用核函数
167             if (eta>=0): return 0
168             self.alphas[j] -= self.labelMat[j] * (Ei - Ej)/eta
169             self.alphas[j] = clipAlpha(self.alphas[j],H,L)
170             #更新新出现的aj
171             self.updataEk(j)
172             if (abs(self.alphas[j] - alphaJold)<0.00001):
173                 print('J not move')
174             self.alphas[i] += self.labelMat[j]*self.labelMat[i]*(alphaJold-self.alphas[j])
175             self.updataEk(i)#更新新出现的ai
176             b1 = self.b - Ei - self.labelMat[i] *(self.alphas[i] - alphaIold)*\
177                 self.K[i,i] - self.labelMat[j]*(self.alphas[j]-alphaJold)*self.K[i,j]
178             b2 = self.b - Ej - self.labelMat[i] *(self.alphas[i] - alphaIold)*\
179                 self.K[i,j] - self.labelMat[j]*(self.alphas[j]-alphaJold)*self.K[j,j]
180             if (self.alphas[i]>0 and self.alphas[i]<self.C): self.b = b1
181             elif (self.alphas[j]>0 and self.alphas[j]<self.C): self.b = b2
182             else:self.b = (b1+b2)/2.0
183             return 1
184         else:
185             return 0
186 
187 def smoP(dataMatIn, classLabels, C, toler, maxIter, kTup):  # full Platt SMO
188     self = optStruct(np.mat(dataMatIn), np.mat(classLabels).transpose(), C, toler, kTup)
189     iter = 0
190     entireSet = True;
191     alphaPairsChanged = 0
192     while (iter < maxIter) and ((alphaPairsChanged > 0) or (entireSet)):
193         alphaPairsChanged = 0
194         if entireSet:  # go over all
195             for i in range(self.m):
196                 alphaPairsChanged += self.innerL(i)
197                 print('fullSet iter:%d, i=%d, pair change:%d' % (iter, i, alphaPairsChanged))
198             iter += 1
199         else:  # go over non-bound (railed) alphas
200             nonBoundIs = np.nonzero((self.alphas.A > 0) * (self.alphas.A < C))[0]
201             for i in nonBoundIs:
202                 alphaPairsChanged += self.innerL(i)
203                 print('nonBound iter:%d, i=%d, pair change:%d' % (iter, i, alphaPairsChanged))
204             iter += 1
205         if entireSet:
206             entireSet = False  # toggle entire set loop
207         elif (alphaPairsChanged == 0):
208             entireSet = True
209         print("iteration number: %d" % iter)
210         return self.b, self.alphas
211 #生成核函数,注意这里核函数的计算公式,见博文对其进行说明！
212 def kernelTrans(X,A,kTup):
213     m,n = X.shape
214     K = np.mat(np.zeros([m,1]))
215     if (kTup[0]=='lin'):K = X*A.T
216     elif(kTup[0]=='rbf'):
217         for j in range(m):
218             deltaRow = X[j,:] - A
219             K[j] = deltaRow * deltaRow.T
220         K = np.exp(K/(-1*kTup[1]**2))
221     else:raise NameError('Houston We have a problem')
222     return K
223 def testRbf(k1 = 1.3):
224     dataArr, labelArr, dataLbel = loadDataSet('testSetRBF.txt')
225     b, alphas = smoP(dataArr,labelArr,200,0.0001,10000,('rbf',k1))
226     dataMat = np.mat(dataArr)
227     labelMat = np.mat(labelArr).T
228     svInd = np.nonzero(alphas.A>0)[0]#支持向量a
229     sVs = dataMat[svInd]#支持向量X
230     labelSV = labelMat[svInd]
231     print("There are %d Support Vector"%(sVs.shape[0]))
232     m, n = dataMat.shape
233     errorCount = 0
234     for i in range(m):
235         kernelEval = kernelTrans(sVs,dataMat[i,:],('rbf',k1))
236         predict = kernelEval.T * np.multiply(labelSV,alphas[svInd])+b
237         if(np.sign(predict)!=np.sign(labelArr[i])):errorCount+=1
238     print("The training error is: %f"%(float(errorCount/m)))
239     dataArr, labelArr, datalabel = loadDataSet('testSetRBF2.txt')
240     errorCount = 0
241     dataMat = np.mat(dataArr)
242     labelMat = np.mat(labelArr).T
243     m, n = dataMat.shape
244     for i in range(m):
245         kernelEval = kernelTrans(sVs, dataMat[i,:], ('rbf', k1))
246         predict = kernelEval.T * np.multiply(labelSV, alphas[svInd]) + b
247         if (np.sign(predict) != np.sign(labelArr[i])): errorCount += 1
248     print("The test error is: %f" %(float(errorCount / m)))
249 
250 if __name__ == '__main__':
251 
252     testRbf(1.3)

　　　　2.1.4手写数字识别测试

  1 import numpy as np
  2 import matplotlib.pyplot as plt
  3 
  4 #预处理数据
  5 def loadDataSet(fileName):
  6     dataMat  = []
  7     labelMat = []
  8     fr = open(fileName,'r')
  9     for line in fr.readlines():
 10         lineArr = line.strip().split('\t')
 11         dataMat.append([float(lineArr[0]),float(lineArr[1])])
 12         labelMat.append(float(lineArr[2]))
 13     a = np.mat(dataMat)
 14     b = np.mat(labelMat).T
 15     DataLabel = np.array(np.hstack((a,b)))
 16     return dataMat, labelMat, DataLabel
 17 #随机
 18 def selectJrand(i,m):
 19     j = i
 20     while(j==i):
 21         j = int(np.random.uniform(0,m))
 22     return j
 23 #约束之后的aj
 24 def clipAlpha(aj,H,L):
 25     if aj>H:
 26         aj = H
 27     elif aj<L:
 28         aj = L
 29     return aj
 30 #C:松弛系数
 31 #maxIter:迭代次数
 32 def smselfimple(dataMatIn,classLabels,C,toler,maxIter):
 33     dataMatraix  = np.mat(dataMatIn)
 34     labelMatraix = np.mat(classLabels).transpselfe()
 35     b =0
 36     m,n = dataMatraix.shape
 37     alphas = np.mat(np.zerself((m,1)))#系数都初始化为0
 38     iter = 0
 39     while(iter<maxIter):#大循环是最大迭代次数
 40         alphaPairsChange = 0
 41         for i in range(m):#样本训练
 42             #预测值,具体看博客手写图片
 43             fXi = float(np.multiply(alphas,labelMatraix).T*(dataMatraix*dataMatraix[i,:].T))+b
 44             #误差
 45             Ei  = fXi - float(labelMatraix[i])
 46             #满足条件才能更新a,b的值,感觉这里的labelMat[i]不影响结果
 47             if(((labelMatraix[i]*Ei<-toler) and (alphas[i]<C))\
 48                 or ((labelMatraix[i]*Ei)>toler) and (alphas[i]>0)):
 49                 j = selectJrand(i,m)#随机选择一个不同于i的[0,m]
 50                 fXj = float(np.multiply(alphas,labelMatraix).transpselfe()\
 51                             *(dataMatraix*dataMatraix[j,:].T))+b
 52                 Ej  = fXj - float(labelMatraix[j])
 53                 alphaIold = alphas[i].copy()
 54                 alphaJold = alphas[j].copy()
 55                 if (labelMatraix[i] != labelMatraix[j]):
 56                     L = max(0,alphas[j]-alphas[i])
 57                     H = min(C,C+alphas[j]-alphas[i])
 58                 else:
 59                     L = max(0,alphas[i]+alphas[j]-C)
 60                     H = min(C,alphas[i]+alphas[j])
 61                 if (L==H):
 62                     print('L==H')
 63                     continue
 64                 #计算
 65                 eta = 2.0*dataMatraix[i,:]*dataMatraix[j,:].T\
 66                         - dataMatraix[i,:]*dataMatraix[i,:].T\
 67                         - dataMatraix[j,:]*dataMatraix[j,:].T
 68                 if (eta>0):
 69                     print("eta>0")
 70                     continue
 71                 #更新a的新值j
 72                 alphas[j] -= labelMatraix[j]*(Ei - Ej)/eta
 73                 #修剪aj
 74                 alphas[j] = clipAlpha(alphas[j],H,L)
 75                 if (abs(alphas[j] - alphaJold) < 0.00001):
 76                     print("aj not moving")
 77                 #更新ai
 78                 alphas[i] += labelMatraix[j]*labelMatraix[i]*(alphaJold - alphas[j])
 79                 #更新b1,b2
 80                 b1 = b - Ei - labelMatraix[i]*(alphas[i]-alphaIold)*dataMatraix[i,:]\
 81                               *dataMatraix[i,:].T - labelMatraix[j]*(alphas[j]-alphaJold)*dataMatraix[i,:]*dataMatraix[j,:].T
 82                 b2 = b - Ej - labelMatraix[i]*(alphas[i] - alphaIold)*dataMatraix[i,:]\
 83                               * dataMatraix[j, :].T - labelMatraix[j]*(alphas[j] - alphaJold) * dataMatraix[j,:] * dataMatraix[j,:].T
 84                 #通过b1和b2计算b
 85                 if (0< alphas[i] <C): b = b1
 86                 elif (0<alphas[j]<C): b = b2
 87                 else: b = (b1+b2)/2
 88                 #计算更新次数,用来判断是否训练数据是否全部达标
 89                 alphaPairsChange += 1
 90                 print("iter: %d i:%d pairs:%d "%(iter,i,alphaPairsChange))
 91         #连续的达标次数
 92         if(alphaPairsChange==0): iter +=1
 93         else: iter = 0
 94         print("iteration number: %d"%(iter))
 95     return b, alphas
 96 
 97 #分类函数
 98 def calsWs(alphas,dataArr,classLabels):
 99     X = np.mat(dataArr)
100     labelMat = np.mat(classLabels).T
101     alphas = np.mat(np.array(alphas).reshape((1,100))).T
102     w = np.sum(np.multiply(np.multiply(alphas,labelMat),X),axis=0)
103     return w
104 #文本转化为int
105 def img2vector(filename):
106     returnVect = np.zeros((1,1024))
107     fr = open(filename)
108     for i in range(32):
109         lineStr = fr.readline()
110         for j in range(32):
111             returnVect[0,32*i+j] = int(lineStr[j])
112     return returnVect
113 #完整版SMO
114 class optStruct:
115     def __init__(self,dataMatIn,classLabel,C,toler,kTup):
116         self.X = dataMatIn
117         self.labelMat = classLabel
118         self.C = C
119         self.tol = toler
120         self.m = np.shape(dataMatIn)[0]
121         self.alphas = np.mat(np.zeros((self.m,1)))
122         self.b = 0
123         self.eCache = np.mat(np.zeros((self.m,2)))#存储误差,用于启发式搜索
124         self.K = np.mat(np.zeros((self.m,self.m)))#存储核函数转化后的dataMatIn
125         for i in range(self.m):
126             self.K[:,i] = kernelTrans(self.X,self.X[i,:],kTup)
127     def clacEk(self,k):
128         #计算当前值
129         fXk = float(np.multiply(self.alphas,self.labelMat).T*self.K[:,k]+ self.b)
130         Ek  = fXk - float(self.labelMat[k])
131         return Ek
132     def selecJ(self,i,Ei):
133         maxK = -1
134         maxDeltaE = 0
135         Ej = 0
136         self.eCache[i] = [1,Ei]#存储偏差
137         #A代表mat转换成array类型,nonzero返回非零元素的下标
138         validEcacheList = np.nonzero(self.eCache[:,0].A)[0]
139         if (len(validEcacheList)>1):#启发式选择
140             for k in validEcacheList:
141                 if (k==i):continue#k不能等于i
142                 Ek = self.clacEk(k)#计算绝对偏差
143                 deltaE = abs(Ei - Ek)#相对偏差
144                 if (deltaE >maxDeltaE):
145                     maxK = k
146                     maxDeltaE = deltaE
147                     Ej = Ek
148             return maxK, Ej
149 
150         else:
151             j = selectJrand(i,self.m)#随机选择
152             Ej = self.clacEk(j)#随机绝对偏差
153         return j,Ej
154     def updataEk(self,k):
155         Ek = self.clacEk(k)
156         self.eCache[k] = [k,Ek]
157     def innerL(self,i):
158         Ei = self.clacEk(i)
159         if ((self.labelMat[i]*Ei<-self.tol and self.alphas[i]<self.C)\
160                     or(self.labelMat[i]*Ei>self.tol and self.alphas[i]>0)):
161             j,Ej = self.selecJ(i,Ei)#选择J
162             alphaIold = self.alphas[i].copy()
163             alphaJold = self.alphas[j].copy()
164             #计算L和H的值
165             if (self.labelMat[i] != self.labelMat[j]):
166                 L = max(0,self.alphas[j]-self.alphas[i])
167                 H = min(self.C,self.C+self.alphas[j]-self.alphas[i])
168             else:
169                 L = max(0,self.alphas[j]+self.alphas[i]-self.C)
170                 H = min(self.C,self.alphas[i] +self.alphas[j])
171             if (L==H): return 0
172             #eta = 2.0* self.X[i,:]*self.X[j,:].T - self.X[i,:]*self.X[i,:].T - \
173             #    self.X[j,:]*self.X[j,:].T
174             eta = 2.0*self.K[i,j] - self.K[i,i] - self.K[j,j]#在此应用核函数
175             if (eta>=0): return 0
176             self.alphas[j] -= self.labelMat[j] * (Ei - Ej)/eta
177             self.alphas[j] = clipAlpha(self.alphas[j],H,L)
178             #更新新出现的aj
179             self.updataEk(j)
180             if (abs(self.alphas[j] - alphaJold)<0.00001):
181                 print('J not move')
182             self.alphas[i] += self.labelMat[j]*self.labelMat[i]*(alphaJold-self.alphas[j])
183             self.updataEk(i)#更新新出现的ai
184             b1 = self.b - Ei - self.labelMat[i] *(self.alphas[i] - alphaIold)*\
185                 self.K[i,i] - self.labelMat[j]*(self.alphas[j]-alphaJold)*self.K[i,j]
186             b2 = self.b - Ej - self.labelMat[i] *(self.alphas[i] - alphaIold)*\
187                 self.K[i,j] - self.labelMat[j]*(self.alphas[j]-alphaJold)*self.K[j,j]
188             if (self.alphas[i]>0 and self.alphas[i]<self.C): self.b = b1
189             elif (self.alphas[j]>0 and self.alphas[j]<self.C): self.b = b2
190             else:self.b = (b1+b2)/2.0
191             return 1
192         else:
193             return 0
194 
195 def smoP(dataMatIn, classLabels, C, toler, maxIter, kTup):  # full Platt SMO
196     self = optStruct(np.mat(dataMatIn), np.mat(classLabels).transpose(), C, toler, kTup)
197     iter = 0
198     entireSet = True;
199     alphaPairsChanged = 0
200     while (iter < maxIter) and ((alphaPairsChanged > 0) or (entireSet)):
201         alphaPairsChanged = 0
202         if entireSet:  # go over all
203             for i in range(self.m):
204                 alphaPairsChanged += self.innerL(i)
205                 print('fullSet iter:%d, i=%d, pair change:%d' % (iter, i, alphaPairsChanged))
206             iter += 1
207         else:  # go over non-bound (railed) alphas
208             nonBoundIs = np.nonzero((self.alphas.A > 0) * (self.alphas.A < C))[0]
209             for i in nonBoundIs:
210                 alphaPairsChanged += self.innerL(i)
211                 print('nonBound iter:%d, i=%d, pair change:%d' % (iter, i, alphaPairsChanged))
212             iter += 1
213         if entireSet:
214             entireSet = False  # toggle entire set loop
215         elif (alphaPairsChanged == 0):
216             entireSet = True
217         print("iteration number: %d" % iter)
218         return self.b, self.alphas
219 #生成核函数,注意这里核函数的计算公式,见博文对其进行说明！
220 def kernelTrans(X,A,kTup):
221     m,n = X.shape
222     K = np.mat(np.zeros([m,1]))
223     if (kTup[0]=='lin'):K = X*A.T
224     elif(kTup[0]=='rbf'):
225         for j in range(m):
226             deltaRow = X[j,:] - A
227             K[j] = deltaRow * deltaRow.T
228         K = np.exp(K/(-1*kTup[1]**2))
229     else:raise NameError('Houston We have a problem')
230     return K
231 
232 def testRbf(k1 = 1.3):
233     dataArr, labelArr, dataLbel = loadDataSet('testSetRBF.txt')
234     b, alphas = smoP(dataArr,labelArr,200,0.0001,10000,('rbf',k1))
235     dataMat = np.mat(dataArr)
236     labelMat = np.mat(labelArr).T
237     svInd = np.nonzero(alphas.A>0)[0]#支持向量a
238     sVs = dataMat[svInd]#支持向量X
239     labelSV = labelMat[svInd]
240     print("There are %d Support Vector"%(sVs.shape[0]))
241     m, n = dataMat.shape
242     errorCount = 0
243     for i in range(m):
244         kernelEval = kernelTrans(sVs,dataMat[i,:],('rbf',k1))
245         predict = kernelEval.T * np.multiply(labelSV,alphas[svInd])+b
246         if(np.sign(predict)!=np.sign(labelArr[i])):errorCount+=1
247     print("The training error is: %f"%(float(errorCount/m)))
248     dataArr, labelArr, datalabel = loadDataSet('testSetRBF2.txt')
249     errorCount = 0
250     dataMat = np.mat(dataArr)
251     labelMat = np.mat(labelArr).T
252     m, n = dataMat.shape
253     for i in range(m):
254         kernelEval = kernelTrans(sVs, dataMat[i,:], ('rbf', k1))
255         predict = kernelEval.T * np.multiply(labelSV, alphas[svInd]) + b
256         if (np.sign(predict) != np.sign(labelArr[i])): errorCount += 1
257     print("The test error is: %f" %(float(errorCount / m)))
258 
259 def loadImage(dirName):
260     from os import listdir
261     hwLabel = []
262     trainingFileList = listdir(dirName)
263     m = len(trainingFileList)
264     trainingMat = np.zeros((m,1024))
265     for i in range(m):
266         fileNameStr = trainingFileList[i]
267         fileStr = fileNameStr.split('.')[0]
268         classNumStr = int(fileStr.split('_')[0])
269         if (classNumStr==9):
270             hwLabel.append(-1)
271         else:hwLabel.append(1)
272         trainingMat[i,:] = img2vector('%s/%s'%(dirName,fileNameStr))
273     return trainingMat, np.array(hwLabel)
274 
275 def testDigits(kTup = ('rbf',10)):
276     dataArr, labelArr = loadImage('trainingDigits')
277     b, alphas = smoP(dataArr,labelArr,200,0.0001,10000,kTup)
278     dataMat = np.mat(dataArr);labelMat = np.mat(labelArr).T
279     svInd = np.nonzero(alphas.A>0)[0]
280     sVs = dataMat[svInd]
281     labelSV = labelMat[svInd]
282     print("there are %d Support Vectors"%(int(sVs.shape[0])))
283     m,n = dataMat.shape
284     errorCount = 0
285     for i in range(m):
286         kernelEval = kernelTrans(sVs,dataMat[i,:],kTup)
287         predict = kernelEval.T * np.multiply(labelSV,alphas[svInd]) + b
288         if (np.sign(predict)!=np.sign(labelArr[i])):errorCount+=1
289     print("The training error is: %f"%(float((errorCount)/m)))
290     dataArr, labelArr = loadImage('testDigits')
291     errorCount = 0
292     dataMat = np.mat(dataArr);labelMat = np.mat(labelArr).T
293     m, n = dataMat.shape
294     for i in range(m):
295         kernelEval = kernelTrans(sVs, dataMat[i, :], kTup)
296         predict = kernelEval.T * np.multiply(labelSV, alphas[svInd]) + b
297         if (np.sign(predict) != np.sign(labelArr[i])): errorCount += 1
298     print("The test error is: %f" % (float((errorCount) / m)))