clear all;close all;clc;

mu1=[0 0];
S1=[0.5 0.1];
data1=mvnrnd(mu1,S1,100);
plot(data1(:,1),data1(:,2),'r.');
hold on;

mu2=[1.5 1.5];
S2=[0.4 0.3];
data2=mvnrnd(mu2,S2,100);
plot(data2(:,1),data2(:,2),'g.');

data1 = [data1 zeros(length(data1),1)];
data2 = [data2 ones(length(data2),1)];      %两组数据打标签
data = [data1;data2];                       %数据组合
data = [ones(length(data),1) data];         %数据第一列增加其次项

w = rand(1,3);
alpha = 0.01;
for i=1:1000
    w = w + alpha*(data(:,4)' - 1./(1+exp(-(w*data(:,1:3)'))))*data(:,1:3);     %交叉熵求导迭代
end

x = min(data(:,2))-1:0.1:max(data(:,2))+1;
y = (-w(1)-w(2)*x)/w(3);
plot(x,y,'b');