gistfile1.py

#!/usr/bin/env python
import urllib
import math

def p(str):
    print(str)

def single_perception():
    try:
        fi = urllib.urlopen("http://aoki2.si.gunma-u.ac.jp/R/lr.data")
        data = fi.read()
    except IOError:
        print("url can't open")
        return

    data2 = []
    dd2 = data.split('\r')
    header = dd2.pop(0).split()
    for dd in dd2[1:]:
        dd3 = dd.split()
        if(len(dd3) < 3): continue
        #print dd3
        dd3[0] = float(dd3[0]) / 1000
        dd3[1] = float(dd3[1]) / 1000
        dd3[2] = float(dd3[2])
        data2.append(dd3)

    header = data2.pop(0)
    """p("header:"),
    p(header)
    p( data2 )"""


    def perception(x1,x2,a0,a1,a2):
        s = a0 + a1*x1 + a2*x2
        o = math.exp(s)/(1+math.exp(s))
        return o

    def deda0(data,a0,a1,a2):
        tmp_a = 0
        for dd in data:
            (x1, x2, y) = dd
            tmp_a += y-perception(x1,x2,a0,a1,a2)
        return tmp_a

    def deda1(data,a0,a1,a2):
        tmp_a = 0
        for dd in data:
            (x1, x2, y) = dd
            tmp_a += (y-perception(x1,x2,a0,a1,a2)) * x1
        return tmp_a

    def deda2(data,a0,a1,a2):
        tmp_a = 0
        for dd in data:
            (x1, x2, y) = dd
            tmp_a += (y-perception(x1,x2,a0,a1,a2)) * x2
        return tmp_a

    a0 = 0.1
    a1 = 0.1
    a2 = 0.1
    alpha = 0.1
    for i in range(100000):
        a0 = a0 + alpha * deda0(data2,a0,a1,a2)
        a1 = a1 + alpha * deda1(data2,a0,a1,a2)
        a2 = a2 + alpha * deda2(data2,a0,a1,a2)

    p("a0,a1,a2=%f,%f,%f" % ( a0, a1, a2 ))

if __name__ == "__main__":
    single_perception()