Access to the final Held-Karp lower bound tree

[TryerGit]

Hello,

I would like to access the final Held-Karp lower bound tree for the TSP.
Looking at documentation about it available at : https://developers.google.com/optimization/reference/graph/one_tree_lower_bound

it is not clear to me which function returns the tree. The return value seems to be a double with signature:

const double lower_bound = ComputeOneTreeLowerBound(number_of_nodes, cost_function); //where number_of_nodes is the number of nodes in the TSP and cost_function is a function returning the cost between two nodes.

The actual tree that attains the lower bound does seem to be accessible : See, for e.g., https://ojmo.centre-mersenne.org/item/10.5802/ojmo.11.pdf Page 15, Algorithm 11

I was looking for some algorithm like what boost offers for the normal MST:

std::vector < Edge > spanning_tree;
kruskal_minimum_spanning_tree(g, std::back_inserter(spanning_tree));

which returns in spanning_tree, the actual edges that feature in the MST.

Thank you.