const int ROWS = 3;
    const int COLS = 5;
    Rational A[ROWS][COLS] = {
            {  1,  3, -1, 2, 4 },
            {  2,  6, -3, 2, 3 },
            { -1, -3,  3, 2, 6 },
    };

    Rational *As[ROWS];
    for (int i = 0; i < ROWS; i++) {
        As[i] = A[i];
    }
    rref(As, ROWS, COLS);