clear;
np = 8;
I = double(checkerboard(np)); 
m = size(I,1);

H = fspecial('gaussian',50,2);
B = imfilter(I,H,'replicate');
subplot(221);imshow(I,[]);     title('Original');
subplot(222);imshow(B,[]); title('Blurred');

tol = 1.e-2; maxit = 400;
u0 = B(:); t = 2.e+2;

if 1;
t0 = cputime;
[u1,iter,nf] = myGD(@TVL2B,u0,tol,maxit,u0,t,m,H);
tcpu = cputime - t0;
[f,g] = TVL2B(u1,u0,t,m,H);
fprintf(' myGD:  iter %3i, nf = %4i, tcpu = %6.2e\n',iter,nf,tcpu)
fprintf(' myGD:  f = %12.6e, norm(g) = %9.3e \n\n',f,norm(g))
end

if exist('myCG');
t0 = cputime;
[u2,iter,nf] = myCG(@TVL2B,u0,tol,maxit,u0,t,m,H);
tcpu = cputime - t0;
[f,g] = TVL2B(u2,u0,t,m,H);
fprintf('myCG:  iter %3i, nf = %4i, tcpu = %6.2e\n',iter,nf,tcpu)
fprintf('myCG:  f = %12.6e, norm(g) = %9.3e \n\n',f,norm(g))
end

U = reshape(u1,m,m);
subplot(223);imshow(U,[]); title('Deblurred by GD');
U = reshape(u2,m,m);
subplot(224);imshow(U,[]); title('Deblurred by CG-PR');