Jacobi & Gauss-Serdel

function [y,n] = jacobi(A,b,x0,ep)
    D = diag(diag(A));
    L = -tril(A,-1);
    U = -triu(A,1);
    B = D\(L+U);
    f = D\b;
    y = B*x0+f;
    n = 1;
    while( norm(y-x0) >= ep)
        x0 = y;
        y = B*x0+f;
        n = n+1;
    end

function [y,n] = gaussserdel(A,b,x0,ep)
    D = diag(diag(A));
    L = -tril(A,-1);
    U = -triu(A,1);
    B = (D-L)\U;
    f = (D-L)\b;
    n = 0;
    y = B*x0+f;
    while( norm(y-x0) >= ep)
        x0 = y;
        y = B*x0+f;
        n = n+1;
    end