“…Collatz et al [1] had wanted to obtain all graphs of order n with r(G) < n. Until today, this problem is also unsolved. In mathematics, the rank (or nullity, inertia index) of a graph has attracted a lot of researchers' attention, they focus on the bounds for the rank (or nullity, inertia index) of a simple graph G [4,6,11,23,24,25,26,34], a signed graph [3,5,8,15,19,32], an oriented graph [12,14,16,20,21,28] and a mixed graph [2,29] and so on.…”