function x_new = it_min_l2_w_fast(Phi,y,x_old,eps);
x_eps = (abs(x_old).^2+eps^2).^(0.5);
S = size(Phi);
Dk = kron(x_eps,ones(1,S(1)));
x_new = Phi'*((Phi*(Dk.*Phi'))\y);
x_new = x_eps.*x_new;
%x_new = ((D*Phi')/(Phi*D*Phi'))*y;