How to fill a tree branch with a std::vector of a vector

ROOT
1

Hi Rooters,
I am trying to fill a TTree with an std::vector of a vector. I am not sure about the syntax to use on the Branch method. Could you please have a look in the attached code and tell me from where the problem comes.

—> sorry I cannot attach the file :frowning: … I will try to put the codes below :

[code]–> in the .hh
Int_t Nsampler;
Int_t n_hits[200];
std::vector <Float_t> x0[200],xp0[200],y0[200],yp0[200];
std::vector <Float_t> E0[200],z0[200],x[200],xp[200],y[200];
std::vector <Float_t> yp[200],E[200],z[200],weight[200];
std::vector <Int_t> part[200],nev[200], pID[200],theID[200],track_id[200];

–> in the .cc
SamplerTree->Branch(“Nsampler”,&Nsampler,“Nsampler/I”);
SamplerTree->Branch(“n_hits”,&n_hits,“h_hits/I”);
SamplerTree->Branch(“x”,x,“std::vector<Float_t> x[Nsampler]/F”);
SamplerTree->Branch(“x0”,x0,“std::vector<Float_t> x0[Nsampler]”);
SamplerTree->Branch(“xp0”,xp0,“std::vector<Float_t> xp0[Nsampler]”);
SamplerTree->Branch(“y0”,y0,“std::vector<Float_t> y0[Nsampler]”);
SamplerTree->Branch(“yp0”,yp0,“std::vector<Float_t> yp0[Nsampler]”);
SamplerTree->Branch(“E0”,E0,“std::vector<Float_t> E0[Nsampler]”);
SamplerTree->Branch(“z0”,z0,“std::vector<Float_t> z0[Nsampler]”);
SamplerTree->Branch(“xp”,xp,“std::vector<Float_t> xp[Nsampler]”);
SamplerTree->Branch(“y”,y,“std::vector<Float_t> y[Nsampler]”);
SamplerTree->Branch(“yp”,yp,“std::vector<Float_t> yp[Nsampler]”);
SamplerTree->Branch(“E”,E,“std::vector<Float_t> E[Nsampler]”);
SamplerTree->Branch(“z”,z,“std::vector<Float_t> z[Nsampler]”);
SamplerTree->Branch(“part”,part,“std::vector<Int_t> part[Nsampler]”);
SamplerTree->Branch(“nev”,nev,“std::vector<Int_t> nev[Nsampler]”);
SamplerTree->Branch(“pID”,pID,“std::vector<Int_t> pID[Nsampler]”);
SamplerTree->Branch(“tID”,track_id,“std::vector<Int_t> tID[Nsampler]”);

for (G4int ks=0; ks<nSamplers; ks++)
{
    n_hits[ks]=0;
    x0[ks].clear();
    xp0[ks].clear();
    y0[ks].clear();
    yp0[ks].clear();
    E0[ks].clear();
    z0[ks].clear();
    x[ks].clear();
    xp[ks].clear();
    y[ks].clear();
    yp[ks].clear();
    E[ks].clear();
    z[ks].clear();
    weight[ks].clear();
    part[ks].clear();
    nev[ks].clear();
    pID[ks].clear();
    track_id[ks].clear();
}

for (G4int i=0; i<hc->entries(); i++)
 {
   
     G4int ksampler = names[(*hc)[i]->GetName()];
     name=(*hc)[i]->GetName();
     n_hits[ksampler]++;

     x0[ksampler].push_back((*hc)[i]->GetInitX() / micrometer);
     xp0[ksampler].push_back((*hc)[i]->GetInitXPrime()); 
     y0[ksampler].push_back((*hc)[i]->GetInitY() / micrometer);
     yp0[ksampler].push_back((*hc)[i]->GetInitYPrime()); 
     E0[ksampler].push_back((*hc)[i]->GetInitMom() / GeV);    
     z0[ksampler].push_back((*hc)[i]->GetInitZ() / m); 
     x[ksampler].push_back((*hc)[i]->GetX()/ micrometer); 
     xp[ksampler].push_back((*hc)[i]->GetXPrime()); 
     y[ksampler].push_back((*hc)[i]->GetY() / micrometer); 
     yp[ksampler].push_back((*hc)[i]->GetYPrime()); 
     E[ksampler].push_back((*hc)[i]->GetMom() / GeV); 
     z[ksampler].push_back((*hc)[i]->GetZ() / m); 
     weight[ksampler].push_back((*hc)[i]->GetWeight());
     part[ksampler].push_back((*hc)[i]->GetPDGtype()); 
     nev[ksampler].push_back((*hc)[i]->GetEventNo()); 
     pID[ksampler].push_back((*hc)[i]->GetParentID()); 
     track_id[ksampler].push_back((*hc)[i]->GetTrackID());
     Nsampler=nSamplers;
     sTree->Fill();
 }

[/code]

thanks a lot,

Hayg

2

Hi,

The leaflist method of branch creation (the one you are using) can only handle simple types (int, float, etc). For your purpose you need to wrap those vector into a class or struct, generate a dictionary (for example ACLiC) and create a single object branchMystruct *sampler= new MyStruct; ... tree->Branch("sampler",&sampler);See the User’s Guide for more details.

Cheers,
Philippe