hi Anne-Sylvie,
you seem to be using some nontrivial way of filling the ROOT ntuple,
such that you end up with branch names like "_1"... anyway, you could try
tv__tree->SetBranchAddress("_1.nhitcot",&nhitcot2);
best, Pasha
Anne-Sylvie Nicollerat wrote:
>
> Hello !
>
> I am trying to read the variables from a tree (named Tracks), using the
> following macro (that I start after having started the tree viewer):
>
> {
> tv__tree = (TTree *) gROOT->FindObject("Tracks");
> tv__tree_list->Add(tv__tree);
>
> Int_t nhitcot2;
> Int_t nhitax2;
> Int_t nhitst2;
>
> tv__tree->SetBranchAddress("nhitcot",&nhitcot2);
> tv__tree->SetBranchAddress("nhitax",&nhitax2);
> tv__tree->SetBranchAddress("nhitst",&nhitst2);
> ....
> }
>
> Then root returns me the following error message :
>
> Error in <TTree::SetBranchAddress>: unknown branch -> nhitcot
> Error in <TTree::SetBranchAddress>: unknown branch -> nhitax
> Error in <TTree::SetBranchAddress>: unknown branch -> nhitst
>
> When I look in the contents of my tree, doing tv__tree->Print(), I get
> the following:
>
> root [1] tv__tree->Print()
> ******************************************************************************
>
> *Tree :Tracks :
> Tracks *
> *Entries : 48820 : Total = 3536541 bytes File Size =
> 3536541 *
> * : : Tree compression factor =
> 1.00 *
> ******************************************************************************
>
> *Br 0 :_1 :
> alg/I:charge/I:d0/F:eta/F:event/I:nhitax/I:nhitcot/I: *
> * |
> nhitsil/I:nhitsilphi/I:nhitsilst/I:nhitsilz/I:nhitst/I:pT/F: *
> * |
> paralg/I:phi0/F:run/I:trknum/I:z0/F *
> *Entries : 48820 : Total Size= 3515490 bytes File Size =
> 3515490 *
> *Baskets : 110 : Basket Size= 32000 bytes Compression=
> 1.00 *
>
> I think the suspicious thing is the 0:_1 thing. It look as the variables
> are not directly accessible. Actually when I try to access the tree
> variables from the browser, I first come to a _1 leave that I have to
> open to access the tree variables.
>
> Just another thing: I can for instance plot an histogram directly from
> the viewer and then root executes the following command :
> tv__tree->Draw("_1.nhitcot","","hist", 48820, 0);
>
> Do you know how I could acces the arguments of the tree in my macro ?
>
> Thanks a lot
>
> Anne-Sylvie
>
> --
> -----------------------------------
> Anne-Sylvie Nicollerat
> office 327-52-56, phone 1-630-840-3899
> Fermilab/CDF MS 223 PO box 500,
> Batavia, IL 60510 USA
>
> "Pour le croyant Dieu se trouve au debut, pour le physicien au terme de toute pensee." (Planck)
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