Table 2 Breadth First Search (BFS) algorithm for identifying target controllable subspace

Input: Target control tree TCT ≡ (V _TCT , E _TCT ), node v _i

Initialize: TCS(v _i ) = ∅  , N₀ ={v _i };

While N _k ≠ ∅  (k ≥ 1)

Find the neighbor nodes of all nodes in N _k-1 layer, denoted by N _k ;

end while

Add the reachable nodes in R₀ to TCS(v _i );

Output: The target controllable subspace of nodev _i , TCS(v _i )