q=0;
x=zeros(N1);
X=zeros(N1);
while q<2000
for n=1:N
if n==1
X(n1)=abs(b(n1))-A(nn+1:N)*x(n+1:N1);
else if n<N
X(n1)=abs(b(n1))-(A(n1:n-1)*X(1:n-11)+A(nn+1:N)*x(n+1:N1));
else n==N
X(n1)=abs(b(n1))-A(n1:n-1)*X(1:n-11);
end
X(n1)=max(X(n1)0);
x=X;
q=q+1;
