Axel,
In the development version coming very soon, I have added
a few essential comments in the header of TTree::CloneTree.
These comments are also valid for your version.
Please try and let me know:
TTree *TTree::CloneTree(Int_t nevents)
{
// Create a clone of this tree and copy nevents
// By default copy all events
//
// IMPORTANT: Before invoking this function, the branch addresses
// of this TTree must have been set.
// For examples of CloneTree, see tutorials
// -copytree:
// Example of Root macro to copy a subset of a Tree to a new Tree
// The input file has been generated by the program in
$ROOTSYS/test/Event
// with Event 1000 1 1 1
// -copytree2:
// Example of Root macro to copy a subset of a Tree to a new Tree
// One branch of the new Tree is written to a separate file
// The input file has been generated by the program in
$ROOTSYS/test/Event
// with Event 1000 1 1 1
Rene Brun
On Wed, 26 Aug 1998, Axel Schwank wrote:
> Dear ROOT developers,
> I wanted to provide you with an example Tree to show problmes in the limit
> estimation of TTree::Draw(). Therefore, I wanted to copy the Tree, but
> only some branches of it. But I wasn't even able to clone the Tree.
> I did
>
> TFile *f = new TFile("SomeFile.root"); // contains a Tree named "T"
> TTree *T = (TTree*)f->Get("T");
> TTree *T2 = new TTree("T2","Limit estimation test");
> T2 = T->CloneTree();
>
> **** Break **** Segmentation fault ******
>
> Is this correct in principle?
> I tried with and without loading my shared lib.
>
> Well, anyway, how do I best copy only selected Branches of a Tree?
> I thought
> 1) Connecting a file and retrieving the Tree
> 2) control the active brances with TTree::SetBranchStatus()
> 3) clone the Tree to another one
>
> Does TTree::Clone() respect the list of active branches?
>
> I could provide you with the full Tree, but the size is 34MB.
> But if I made no error in the above commands, it looks like that's the
> only way. Then you could also have a look why the Tree doesn't want to be
> cloned.
>
> Thank you in advance,
> Axel
>
> ********************************
>
> Axel Schwank
>
> DESY H1-F22
> Notkestrasse 85
> D-22607 Hamburg
>
> Rm. 1b/269
> Tel (+49 40) 8998-3560
> Fax (+49 40) 8998-4385
>
> e-mail schwank@mail.desy.de
> Quix 0165-6-2705109
>
> ********************************
>
>
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