np = 32;
I = double(checkerboard(np)); 
m = size(I,1);

Noisy = imnoise(I,'gaussian',0,.1);
subplot(221);imshow(I,[]);     title('Original');
subplot(222);imshow(Noisy,[]); title('Noisy');

tol = 5.e-8; maxit = 100;
u0 = Noisy(:); t = 3;

if 1;
t0 = cputime;
[u1,iter,nf] = myGD(@TVL2N,u0,tol,maxit,u0,t,m);
tcpu = cputime - t0;
[f,g] = TVL2N(u1,u0,t,m);
fprintf(' zGD:  iter %3i, nf = %4i, tcpu = %6.2e\n',iter,nf,tcpu)
fprintf(' zGD:  f = %12.6e, norm(g) = %9.3e \n\n',f,norm(g))
end;

if exist('myCG');
t0 = cputime;
[u2,iter,nf] = myCG(@TVL2N,u0,tol,maxit,u0,t,m);
tcpu = cputime - t0;
[f,g] = TVL2N(u2,u0,t,m);
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

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