float A[] = { 8, 9, 3, 10,

9, 6, 5, 2,

1, 1, 10, 10 };

float Q[3 * 3], R[3 * 4], B[3 * 4];

QR(Q, R, A, 3, 4);

multiply_matrices(B, Q, R, 3, 3, 4); // B should be identical to A

float AA[4 * 3];

float QQ[4 * 4], RR[3 * 3], BB[4*3];

transpose(AA, A, 3, 4);

QR(QQ, RR, AA, 4, 3);

multiply_matrices(BB, QQ, RR, 4, 4, 3); // BB should be identical to AA

return 0;