Re: A problem with TTree::Fill()

You posted the same question at the Forum. See my answer there.

Rene Brun

Stephen Liu wrote:
> Hi, all
>
> I have came up with a strange problem with TTree::Fill(). I have a
> tree with some data and now I want to pick out some of them to form a
> new tree. Here is my code:
>
> void split()
> {
> TFile *input = new TFile(" input.root", "READ");
> TTree *original = (TTree *)input->Get("Train");
>
> Double_t data1;
> Double_t data2;
> Double_t data3;
> Int_t data4;
>
> original->SetBranchAddress(
> "data1", &data1);
> original->SetBranchAddress("data2", &data2);
> original->SetBranchAddress("data3", &data3);
> original->SetBranchAddress("data4", &data4);
>
> TTree *newtree = new TTree("Train", "My New Tree");
> newtree->Branch("data1", &data1, "data1/D");
> newtree->Branch("data2", &data2, "data2/D");
> newtree->Branch("data3", &data3, "data3/D");
> newtree->Branch("data4", &data4, "data4/I");
>
> for(Int_t i = 0; i < original->GetEntries(); i++)
> {
> original->GetEntry(i);
>
> if(data1 > 0.5) newtree->Fill();
>
> }
>
> }
>
> When I run this macro in ROOT v5.14, ROOT gives out following error
> messages while i equals certain values:
>
> Error in <TTree::Fill>: Failed filling branch: Train.data1, nbytes=-1
> 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:Train.data2, nbytes=-1
> 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:Train.data3, nbytes=-1
> 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:Train.data4, nbytes=-1
> 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(...)
>
>
> I checked the value of the branches of the entries which induce the
> error, however they appears quite normal.
> Thanks in advance for any help!
>
> liuk
> 2007.4.30
Received on Tue May 01 2007 - 07:59:43 CEST