字典学习与稀疏表示（一）

clear all  close all  %  A = [1 0.5 -1/2^0.5;      0 (3/4)^0.5 -1/2^0.5];  y = [1,0.5]';  K = 3;  [m,n] = size(A);        % iteration  Rf(:,1) = y;  for k = 1:K            for i = 1:n           ip(i) = abs(Rf(:,k)'*A(:,i));      end      j(k) = find(max(ip)==ip);      Rf(:,k+1) = Rf(:,k) - Rf(:,k)'*A(:,j(k))*A(:,j(k));      Rfnorm(k) = norm(Rf(:,k));  end  R = [A(:,j(1)),A(:,j(2)),A(:,j(3))];  r1 = R(:,1);  r2 = R(:,2);  r3 = R(:,3);  figure,quiver(0,0,y(1),y(2),'r');  hold,quiver(0,0,r1(1),r1(2),'b');  quiver(0,0,r2(1),r2(2),'b');  quiver(0,0,r3(1),r3(2),'b');  display(norm(Rf(:,K+1)));