def check_close_real(x, y, eps=1e-9):
    """Return true iff floats x and y "are close\""""
    # put the one with larger magnitude second
    if abs(x) > abs(y):
        x, y = y, x
    if y == 0:
        return abs(x) < eps
    if x == 0:
        return abs(y) < eps
    # check that relative difference < eps
    return abs((x-y)/y) < eps