JacobiIt

function JacobiIt(A,b)
% pl JacobiIt(A,[1;1],10)

D=diag(diag(A));
L=tril(A,-1);
U=triu(A,1);
B=-inv(D)*(L+U);
f=inv(D)*b;
x=zeros(size(b));
if det(D)==0
    error('Nem létezik D inverze!');
end
maradekok=zeros(10,1);

for k=1:10
    x=B*x+f;
    maradekok(k)=norm(b-A*x);
end
rho=max(abs(eig(B)));
fprintf('A spektrálsugár logaritmusa: %4.2f\n',log(rho));
plot(log(maradekok),'b+')

Not enough input arguments.

Error in JacobiIt (line 4)
D=diag(diag(A));