untitled7.m

用MATLAB编写的支持向量机

clear;
N=50;
n =N/2;
randn('state',6);
x1 = randn(3,n);
y1 = ones(1,n);
x2 = 5+randn(3,n);
y2 = -ones(1,n);

figure;
plot3(x1(1,:),x1(2,:),x1(3,:),'*',x2(1,:),x2(2,:),x2(3,:),'k*');
axis([-3 8 -3 8 -3 8]);
hold on;

X1 = [x1,x2];
Y1 = [y1,y2]; 
X=X1';
y=Y1;
x=X;
C=Inf;
[g,z,a,k,d,m]=matlabsvm1(C,X,y,x)

for i=1:size(k,2)
    plot3(X(k(i),1),X(k(i),2),X(k(i),3),'O')
end
A=sum(a.*(y').*X(:,1));
B=sum(a.*(y').*X(:,2));
E=sum(a.*(y').*X(:,3));
F=sum(a.*(y').*(X*(X(k(1),:))'))-y(k(1));
F1=F+1;
F2=F-1;
[pp,tt]=meshgrid(-3:1:8);
[m1 m2]=size(pp);
z=(F*(ones(m1,m2))-A*pp-B*tt)./E;
z1=(F1*(ones(m1,m2))-A*pp-B*tt)./E;
z2=(F2*(ones(m1,m2))-A*pp-B*tt)./E;
mesh(pp,tt,z)
mesh(pp,tt,z1)
mesh(pp,tt,z2)
xlabel('x1')
ylabel('x2')
zlabel('x3')