感知机算法实现(对偶形式)
误分条件:
import numpy as np
def creatDataSet( ):
group=np.array([[3,3],[4,3],[1,1]])
label=[1,1,-1]
return group,label
def update( x , y , i ):
global a , b , G
a[ i ] += 1
b = b + y
def cal( x , label , row ):
global a , b , G
result=0
for i in range( len(G[ row ]) ):
result += label[ i ] * a[ i ] * G[ row ][ i ]
result += b
result *= label[ row ]
return result
def perceptron_func( group , label ):
global a , b , G
isFind = False
n=group.shape[0]
x_col=group.shape[1]
a = np.zeros(n,dtype=np.int) #初始化
b = 0
G=np.zeros((n,n),dtype=np.int)
#计算Gam矩阵
for i in range( n ):
for j in range( n ):
G[i][j] = group[ i ][ 0 ] * group[ j ][ 0 ] + group[ i ][ 1 ] * group[ j ][ 1 ]
while isFind == False:
for i in range( n ):
if cal(group[ i ] , label , i ) <= 0:
update(group[ i ] , label[ i ] , i )
print(a,b)
break
elif i == n - 1:
print(a,b)
isFind = True
g , l = creatDataSet( )
perceptron_func(g,l)
算法迭代过程:运行结果:
[1 0 0] 1
[1 0 1] 0
[1 0 2] -1
[1 0 3] -2
[2 0 3] -1
[2 0 4] -2
[2 0 5] -3
[2 0 5] -3