周志华机器学习第三章线性模型课后习题3.3matlab编程得到结果不一致怎么办？

Question

用的是matlab编程，得到的结果好像问题蛮大的，不知道是哪里编程出了问题，希望能帮忙看下，谢谢
题目“编程实现对率回归，并给出西瓜数据集3.0a上的结果 ”

clear;clc;
data = csvread('3.0alpha.csv');
[m n] = size(data);

beta0 = [1 1 0]';
sum2=0;
sum1=0;
for i = 1:m
    data1 = [data(i,1:2) 1]';
    sum2 = sum2 + (data1 * data1' * exp(beta0'*data1)/(1 + exp(beta0'*data1)))*(1-exp(beta0'*data1)/(1 + exp(beta0'*data1)));
    sum1 = sum1 - data1*(data(i,3)-exp(beta0'*data1)/(1 + exp(beta0'*data1)));
end
beta = beta0 - inv(sum2)*sum1;

for i = 2:1000
    for j = 1:m
        data1 = [data(j,1:2) 1]';
        sum2 = sum2 + (data1 * data1' * exp(beta'*data1)/(1 + exp(beta'*data1)))*(1-exp(beta'*data1)/(1 + exp(beta'*data1)));
        sum1 = sum1 - data1*(data(j,3)-exp(beta'*data1)/(1 + exp(beta'*data1)));
    end   
    beta = beta - inv(sum2)*sum1;
end
sum = zeros(m,1);
for i = 1:m

    for j = 1:3
        sum(i) = sum(i) + beta(j)*data(i,j);
    end
end
sum

数据如下
0.697 0.46 1
0.774 0.376 1
0.634 0.264 1
0.608 0.318 1
0.556 0.215 1
0.403 0.237 1
0.481 0.149 1
0.437 0.211 1
0.666 0.091 0
0.243 0.267 0
0.245 0.057 0
0.343 0.099 0
0.639 0.161 0
0.657 0.198 0
0.36 0.37 0
0.593 0.042 0
0.719 0.103 0

Answer 1

https://blog.csdn.net/weixin_38648770/article/details/96316613