Merging tree from a final jet

[mgratrix]

I have reconstructed some events using the Cambridge/Aachen algorithm and would like to find the two parents of these jets. I'm looking for a way of accessing the entire merging tree from a final jet—i.e. a function or API call that, for each PseudoJet, gives you the two sub-jets that were merged to form it. Specifically, I was looking for the ability to make a function along the lines of:

function get_jet_parents(jet::PseudoJet, cluster_seq::ClusterSequence)::Union{Tuple{PseudoJet, PseudoJet}, Nothing} if JetReconstruction.has_parents(jet, cluster_seq) parent1, parent2 = JetReconstruction.parents(jet, cluster_seq) return (parent1, parent2) end return nothing end

As far as I know, this package doesn't have these capabilities yet.

[Moelf]

I guess this has some rather large performance implications. But maybe if the api of finding the jets to be clustered is user-friendly enough, one can easily implement this outside

[mgratrix]

The most reliable way I have found to achieve this outside was using the following:

function find_parent_pseudoJets(cs::ClusterSequence, jet::PseudoJet)::Tuple{Union{Nothing, PseudoJet}, Union{Nothing, PseudoJet}} hist_idx = jet._cluster_hist_index jet_history = cs.history[hist_idx] parent1_idx, parent2_idx = jet_history.parent1, jet_history.parent2 parent1_jet = parent1_idx > 0 ? cs.jets[cs.history[parent1_idx].jetp_index] : nothing parent2_jet = parent2_idx > 0 ? cs.jets[cs.history[parent2_idx].jetp_index] : nothing return parent1_jet, parent2_jet end

I am leaving this as a record for anyone else trying to do the same thing. While there is probably a more efficient approach, this was the most reliable I could find for now.