The search tree exploring routines

Tree.ios_tree_size()

Determine size of the branch-and-bound tree

Tree.ios_curr_node()

Determine current active subproblem

Tree.ios_next_node(int node)

Determine next active subproblem

Tree.ios_prev_node(int node)

Determine previous active subproblem

Tree.ios_up_node(int node)

Determine parent subproblem

Tree.ios_node_level(int node)

Determine subproblem level

Tree.ios_node_bound(int node)

Determine subproblem local bound

Tree.ios_best_node()

Find active subproblem with best local bound