clear all; close all;

n=40;
a = zeros(n,n); %a=rand(n);
for i=1:n-1
   a(i,i+1) = 1; a(i+1,i)=1; a(i,i) = -2;
end
a(n,n)=-2;

c=ones(n,1);  b=a*c;
tol=1e-6; x0=zeros(n,1); kmax=10000; w=1.9;

[x,k]=my_sor(a,b,x0,w,tol,kmax);

norm(x-inv(a)*b)