n=100;
e=ones(n,1);

A=spdiags([e -4*e 6*e -4*e e],-2:2,n,n);
A(1,1)=5;
A(end,end)=5;
b=zeros(n,1);b(1)=1;

[res1,sol] = CG (A, b, e, 500, 1e-20);
[res2,x] = fom (A, b, e, 500, 1e-20);

semilogy(1:length(res1),res1,'b-',1:length(res2),res2,'r-','LineWidth',2)