% pca.m
% copyright (c) 1997 by Yu Hen Hu
% a demonstration of principal component analysis to synthesized data
% data are generated using dgen2.m
% then projected into two eigenvectors and displayed
% created: 10/9/97

clear all; clf
mv=[-1 .5; -.5 .5; 0.2 0.1]
x=dgen2([30 20],mv);
plot(x(:,1),x(:,2),'o');
[v,d]=eig(x'*x);
y1=x*v(:,1)*v(:,1)';
y2=x*v(:,2)*v(:,2)';
plot(x(:,1),x(:,2),'o',y1(:,1),y1(:,2),'x',y2(:,1),y2(:,2),'*')