Unable to access a variable from a branch structured similarly to std::vector<std::set<int16_t>>

ROOT
1

Dear experts,
I am trying to access a variable from a branch structured similarly to std::vector<std::set<int16_t>>
I am trying to access the variable with the following lines of code in the macro

static constexpr Int_t kMaxPFCandidates = 1167;
std::set<int> PFCandidates_regionsOfInterest_[kMaxPFCandidates];
TBranch        *b_PFCandidates_regionsOfInterest_;
fChain->SetBranchAddress("PFCandidates.regionsOfInterest_",PFCandidates_regionsOfInterest_, &b_PFCandidates_regionsOfInterest_);

Now in the event loop

for (Long64_t jentry=0; jentry<nentries;jentry++){     
      Long64_t ientry = LoadTree(jentry);     
         for (int iPFcan=0; iPFcan < PFCandidates_; iPFcan++){            
                if (PFCandidates_>0){
                std::set<int> mySet = PFCandidates_regionsOfInterest_[iPFcan];             
                cout<<"mySet.size()\t " <<mySet.size<<endl;             
              }
          }
}

The set’s size appears to be zero, indicating that I might be unable to retrieve PFCandidates.regionsOfInterest_. Is there something I’m overlooking, or do objects like std::vector<std::set> require a different access method than SetBranchAddress?

Best
Prafulla

2

Maybe @pcanal can give some hints

3

Hi,

The challenge is that you have a collection of unsplit objects and those are harder to get to. The easiest solution is to consider moving your code to use RDataFrame.

Cheers,
Philippe.