n = 500;

t1 = zeros(1, n);
t2 = zeros(1, n);
t3 = zeros(1, n);

diff1 = zeros(1, n);
diff2 = zeros(1, n);
diff3 = zeros(1, n);

x = 2 : 10: n;

A = [4, 2; 5, 3];

for i = 2 : 10 : n

    disp(i);

    tc1 = 0;
    tc2 = 0;
    tc3 = 0;

    while(abs(det(A)) < 0.00001)
        A = rand(i);
    end

    medium = 10;

    for j = 1 : medium
        tStart = tic;
        [Q, R] = qr(A);

        tc1 = tc1 + toc(tStart);

        tStart = tic;
        [Q1, R1] = qr_c(A);

        tc2 = tc2 + toc(tStart);

        tStart = tic;
        [Q2, R2] = qr_M(A);

        tc3 = tc3 + toc(tStart);
    end

    t1(i) = tc1 / medium;
    t2(i) = tc2 / medium;
    t3(i) = tc3 / medium;

    diff1(i) = sqrt(sum(sum((A - Q * R) .^ 2)));
    diff2(i) = sqrt(sum(sum((A - Q1 * R1) .^ 2)));
    diff3(i) = sqrt(sum(sum((A - Q2 * R2) .^ 2)));

    A = rand(i + 1);
end

figure(1);

plot(x, t1(2 : 10 :end), 'k', x, t2(2 : 10: end), 'b', x, t3(2 : 10: end), 'm');
grid on;

legend('qr(A)', 'qr_c(A)', 'qr_M(A)');

xlabel('n');
ylabel('t');

title('Latency');

figure(2);

plot(x, diff1(2 : 10:end), 'k', x, diff2(2 : 10:end), 'b', x, diff3(2 : 10:end), 'm');

grid on;

legend('qr(A)', 'qr_c(A)', 'qr_M(A)');

xlabel('n');
ylabel('y');

title('Accuracy');