>> A = rand(2,2) A = 0.9501 0.6068 0.2311 0.4860 >> eig(A) ans = 1.1586 0.2775 >> [x] = L2_ball(1); >> for i=1:501, y(:,i) = A*x(:,i); end >> for i=1:501, L2(i) = sqrt( y(1,i)^2 + y(2,i)^2 ); end >> subplot(2,2,1) >> hold off >> plot(x(1,:),x(2,:)) >> title('ball in L_2') >> subplot(2,2,2) >> plot(y(1,:),y(2,:)) >> title('A applied to ball in L_2') >> axis([-1.5,1.5,-1.5,1.5]) >> subplot(2,1,2) >> plot(t,L2) >> axis([0,2*pi,0,1.5]) >> max(L2) ans = 1.2212 >> min(L2) ans = 0.2633 >> title('the L2 norm of Ax for values of x around the ball') >> print -dps fig3.ps >> quit 17673 flops.