perceptron.py

# coding:utf-8

import numpy as np
import math
import matplotlib.pyplot as plt
import random

dim = 2
data = [((-0.5,-0.3), -1), ((-0.4,-0.2), -1), ((-0.5,0.3), -1) , ((1.0, 1.0), 1), ((1.0, 0.0), 1), ((-0.5, 0.8), 1)]

def phi(x):
    return x

def main():
    weight = np.matrix([random.random() for i in range(dim)]).T
    ita = 1.0
    flag = True
    while flag:
        flag = False
        for i, x in enumerate(data):
            p = weight.T.dot(np.matrix(phi(x[0])).T)[0,0] * x[1]
            if p > 0:
                continue
            flag = True
            weight = weight + np.matrix(phi(x[0])).T * x[1]

    plt.scatter([x[0][0]  for x in data if x[1] == 1], [x[0][1] for x in data if x[1] == 1])
    plt.scatter([x[0][0]  for x in data if x[1] == -1], [x[0][1] for x in data if x[1] == -1], c="red")
    x = np.arange(-1,1,0.01)
    y = -weight[0,0]/weight[1,0] * x
    plt.plot(x,y)
    plt.show()

if __name__=='__main__':
    main()