How to rewrite TTree?

ROOT
1

I have tree (say) tree1. I created Class by tree1->MakeClass("MyProcess"). In Loop() I have:

TFile *out = new TFile( filename, "RECREATE" );  
  
  TBranch *nb1 = fChain->Branch( "dev1", &dev1, "dev1/D" );
  TBranch *nb2 = fChain->Branch( "dev2", &dev2, "dev2/D" );
  TBranch *nb3 = fChain->Branch( "pi0pi0", &pi0pi0, "pi0pi0[2]/D" );
  TBranch *nb4 = fChain->Branch( "pi0omega", &pi0omega, "pi0omega[2]/D" );
  TBranch *nb5 = fChain->Branch( "omega", &omega, "omega[2]/D" );
  TBranch *nb6 = fChain->Branch( "mpair", &mpair, "mpair[10]/F" );
  TBranch *nb7 = fChain->Branch( "mtriple", &mtriple, "mtriple[10]/F" );

you can see I want to add new branches to tree1. Then

...
     fChain->Fill();
  }
  fChain->Write();
  out->Close();
}

It seems like code works until fChain->Write() line. After that Segmentation violation appears.
How to write new tree in file properly?

2

As in your previous topic, move the TFile declaration in the Selector definition, at the same location than the TChain is declared, e.g.:

     TFile *out;
     TChain *fChain;

And then change you code as:

  out = new TFile( filename, "RECREATE" );
  
  TBranch *nb1 = fChain->Branch( "dev1", &dev1, "dev1/D" );
  ...

Cheers, Bertrand.

3

I think segmentation violation was caused by my typo in code. But now after adding TFile *out
in MyProcess.h the same error appears:

Error in <TTree::Fill>: Failed filling branch:Selected.mpair, nbytes=-1, entry=35458
 This error is symptomatic of a Tree created as a memory-resident Tree
 Instead of doing:
    TTree *T = new TTree(...)
    TFile *f = new TFile(...)
 you should do:
    TFile *f = new TFile(...)
    TTree *T = new TTree(...)
Error in <TTree::Fill>: Failed filling branch:Selected.mtriple, nbytes=-1, entry=35458
4

This is what in MyProcess.h:

 public :
     TFile          *out;
     TTree          *fChain;   //!pointer to the analyzed TTree or TChain
     Int_t           fCurrent; //!current Tree number in a TChain
 ...
MyProcess::MyProcess(TTree *tree) : out(0), fChain(0)

And in MyProcess.C:

...
 out = new TFile( filename, "RECREATE" );
  
    TBranch *nb1 = fChain->Branch( "dev1", &dev1, "dev1/D" );
    TBranch *nb2 = fChain->Branch( "dev2", &dev2, "dev2/D" );
...
5

And where do you create your TTree (fChain = new TTree(...))?

6

As a side note, fChain is a TSelector is usually for the input. For the output you likely need to create a different data member (so that, at least, to avoid confusion).

7

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