逻辑回归原理与实现

最新推荐文章于 2024-05-27 23:11:21 发布

caicaiatnbu

最新推荐文章于 2024-05-27 23:11:21 发布

阅读量869

点赞数

CC 4.0 BY-SA版权

分类专栏： ML算法实现-python

本文链接：https://blog.youkuaiyun.com/caicaiatnbu/article/details/82727025

ML算法实现-python 专栏收录该内容

11 篇文章

订阅专栏

本文介绍了逻辑回归的基本原理，并提供了相关代码实现。通过链接引用，读者可以深入理解逻辑回归的工作机制。

前提

逻辑回归原理：请参考 https://blog.youkuaiyun.com/zjuPeco/article/details/77165974

代码

import numpy as np
import os

def loadData(dir):
    trainfileList = os.listdir(dir)
    m = len(trainfileList)
    dataArray = np.zeros((m, 1024))
    labelArray = np.ones((m, 1))

    for i in range(m):
        returnArray = np.zeros((1, 1024))
        fileName = trainfileList[i]
        fr = open('%s/%s' %(dir, fileName))

        for j in range(32):
            lineStr = fr.readline()
            for k in range(32):
                returnArray[0, 32*j + k] = int(lineStr[k])
        dataArray[i, :] = returnArray

        label = fileName.split('_')[0]
        labelArray[i] = int(label)
    return dataArray, labelArray

def sigmoid(x):
    return 1.0/(1 + np.exp(-x))

def train(dataArray, labelArray, learning_rate, epoch):
    dataMat = np.mat(dataArray)
    labelMat = np.mat(labelArray)

    m, n = np.shape(dataMat)
    print(m, n)
    weight = np.ones((n, 1))

    for i in range(epoch):
        h = sigmoid(dataMat * weight)

        error = labelMat - h

        weight = weight + learning_rate * dataMat.transpose()*error
    return weight

def test(testdir, weight):
    dataArray, labelArray = loadData(testdir)
    dataMat = np.mat(dataArray)
    labelMat = np.mat(labelArray)

    h = sigmoid(dataMat * weight)
    m = len(h)
    error = 0.

    for i in range(m):
        if int(h[i]) > 0.5:
            print(int(labelMat[i]), 'is classfied as: 1')
            if int(labelMat[i] != 1):
                error += 1
        else:
            print(int(labelMat[i]), 'is classfied as: 0')
            if int(labelMat[i] != 0):
                error += 1

    print(1.0*(m-error) / m)

data, label = loadData('./train')
weight = train(data, label, learning_rate=0.07, epoch=1000)
test('./test', weight)