机器学习简单实验(线性分类)

问题:将一组(x,y)值分类为下列两类函数之一：
2x + 1 = y 第1类
7x + 1 = y 第2类

# -*- coding: utf-8 -*-# easy_linear_learning.pyimport numpy as npimport pylab as plb = 1a = 0.3x = np.array([[1,1,3,],[1,2,3],[1,1,8],[1,2,15],[1,3,7],[1,4,29]])d = np.array([1,1,-1,-1,1,-1])w = np.array([b,0,0])def sgn(v):    if v>0:        return 1    else:        return 0def comy(myw,myx):    return sgn(np.dot(myw.T,myx))def neww(oldw,myd,myx,a):    return oldw + a*(myd - comy(oldw,myx))*myxi = 0for xn in x:    w = neww(w,d[i],xn,a)    i += 1myx = x[:,1]myy = x[:,2]pl.subplot(111)x_max = np.max(myx) + 15x_min = np.min(myx) - 5y_max = np.max(myy) + 50y_min = np.min(myy) - 5pl.xlabel(u"x")pl.xlim(x_min,x_max)pl.ylabel(u"y")pl.ylim(y_min,y_max)for i in xrange(0,len(d)):    if d[i]>0:        pl.plot(myx[i],myy[i],'r*')    else:        pl.plot(myx[i],myy[i],'ro')#Draw the test pointstest  = np.array([b,9,19])if comy(w,test)>0:    pl.plot(test[1],test[2],'b.')else:    pl.plot(test[1],test[2],'bx')test  = np.array([b,9,64])if comy(w,test)>0:    pl.plot(test[1],test[2],'b.')else:    pl.plot(test[1],test[2],'bx')test  = np.array([b,9,16])if comy(w,test)>0:    pl.plot(test[1],test[2],'b.')else:    pl.plot(test[1],test[2],'bx')test  = np.array([b,9,60])if comy(w,test)>0:    pl.plot(test[1],test[2],'b.')else:    pl.plot(test[1],test[2],'bx')testx = np.array(range(0,20))testy = testx*2 + 1.68pl.plot(testx,testy,'g--')pl.show()

分类效果如下: