Filling TTree but setting Event ID manually?

[ferhue]

Why not defining an additional branch with the ‘event id’ ?

Later, you can re-order the tree by event id using TTree::GetTreeIndex

Sorting a tree

I am unfortunately having trouble getting a meaningful result out of my attempts to sort a tree. When I use the technique described above on relatively small files (<50 entries), everything works great. However for somewhat larger files the sorting is clearly wrong. I am attaching two such example files. The actual sorting procedure is the following (also attached): { std::cout<< "Entries:" << ptree->GetEntries()<< std::endl; ptree->BuildIndex("time"); TTreeIndex *I=(TTreeIndex*)ptre…