MATLAB JACOBI'S ALGO

% Algorithm to find approx solution of unknown variables in a system of
% linear equations using Jacobi's method

A = zeros(3, 3);
C = zeros(3, 1);
X = zeros(3, 1);
X1 = 0; X2 = 0; X3 = 0; FLAG = 0;

fprintf('Enter the coefficients of x1 one by one,\nthen the coefficients of x2, and so on:\n');
for i = 1:9
    A(i) = input('Enter the element:   ');
end

fprintf('\nEnter the vector of constants:\n');
for i = 1:3
    C(i) = input('Enter the element:   ');
end

ITR = input('Enter the number of iterations');
TOL = input('Enter the stopping tolerance');

for i = 1:ITR
    X(1) = (1 / A(1,1)) * (C(1) - A(1,2) * X2 - A(1,3) * X3);
    X(2) = (1 / A(2,2)) * (C(2) - A(2,1) * X1 - A(2,3) * X3);
    X(3) = (1 / A(3,3)) * (C(3) - A(3,1) * X1 - A(3,2) * X2);
    if (abs(X(1) - X1) < TOL) && (abs(X(2) - X2) < TOL) && (abs(X(3) - X3) < TOL)
        disp(round(X(1:3), 3))
        disp(i)
        FLAG = 1;
        break
    end
    X1 = X(1); X2 = X(2); X3 = X(3);
end
if FLAG == 0
    disp(round(X(1:3), 3))
end