Re: reading variables from a Tree

In case your tree had been created with automatic split from a top level object, you have to call

   tr1->SetMakeClass(1)
to be able to read the subbranches at given addresses.

Rene Brun

Olaf Hartmann wrote:
> Hi all,
>
> I try to read values from a Tree ... somehow I only get useful data
> for the very first leaf, Npart, which is successfully copied onto the
> corresponding Int_t variable given in SetBranchAddress. All the others
> remains zero ...
>
> The tree is named tr1 (TTree *tr1).
>
> root [104] tr1->SetBranchStatus("*",0)
> root [105] tr1->SetBranchStatus("Npart",1)
> root [106] tr1->SetBranchStatus("pid",1)
> root [107] tr1->SetBranchStatus("ptot",1)
> root [108] tr1.Show(10)
> ======> EVENT:10
> Npart = 6
> Results = (Results*)0x5590fe0
> pid = 2212
> ptot = 0.484537
> root [110] Int_t np,id
> root [111] Double_t ptot
> root [112] tr1->SetBranchAddress("Npart",&np);
> root [113] tr1->SetBranchAddress("pid",&id);
> root [114] tr1->SetBranchAddress("ptot",&ptot);
> root [115] np
> (Int_t)0
> root [116] tr1.Show(10)
> ======> EVENT:10
> Npart = 6
> Results = (Results*)0x5590fe0
> pid = 2212
> ptot = 0.484537
> root [117] np
> (Int_t)6
> root [118] id
> (Int_t)0
> root [119] ptot
> (Double_t)0.00000000000000000e+00
>
> What am I missing there?
>
> Cheers
> Olaf.
>
>
Received on Wed Jul 14 2010 - 14:10:37 CEST