Hi Martin
Apparently you did not get my reply to your mail.
See an example at$ROOTSYS/tutorials/tree2.C
Rene Brun
On Wed, 8 May 2002, Martin Turner wrote:
>
>
> ---------- Forwarded message ----------
> From: Martin Turner <martin@hep.ph.liv.ac.uk>
> To: Rene Brun <Rene.Brun@cern.ch>
> Date: Wed, 8 May 2002 21:59:59 +0100 (BST)
> Subject: Leaves that are a dynamic array.
>
> Hi Root experts. I'm afraid I stumbled across another problem. Hopefully
> this will be quick.
> I want to build arrays of variable size onto a single branch. What is
> wrong with these code snippets:
>
> fLambdaBfile = new TFile("LambdaB_analysis.root","recreate");
> fLambdaB_tree = new TTree("LambdaB_analysis","lambdaB analysis tree");
> fLambda_selection.fcandidate=10;//initialize size of the arrays to
> something
>
> fLambdaB_tree->Branch("Lambda_selection",&fLambda_selection,"fcandidate/I:==>
> flambda_momx[fcandidate]/D:flambda_momy[fcandidate]:flambda_momz[fcandidate]:==>
> ftrack_idi[fcandidate]/I:ftrack_idj[fcandidate]:ftrack_motheridi[fcandidate]:==>
> ftrack_motheridj[fcandidate]:ftrack_granidi[fcandidate]:==>
> ftrack_granidj[fcandidate]:fientry");
>
> members are defined in the header file like this:
>
> struct Lambda_selection{
> Int_t fcandidate;
> Double_t flambda_momx[10];
> Double_t flambda_momy[10];
> Double_t flambda_momz[10];
> Int_t ftrack_idi[10],ftrack_idj[10];
> Int_t ftrack_motheridi[10],ftrack_motheridj[10];
> Int_t ftrack_granidi[10],ftrack_granidj[10];
> Int_t fientry;
> };
> Lambda_selection fLambda_selection;
>
> When defining the branch, if I replace [fcandidate] with [10] I don't have
> a problem, just a lot of wasted memory. fcandidate never exceeds 10. At
> the TTree::Branch the error is:
>
> ERROR leaf:flambda_momx, len=10 and max=0
> ERROR leaf:flambda_momy, len=10 and max=0
> etc.
> Putting fcandidate last on the list gives an "Illegal leaf" error. How do
> I get round this without splitting my leaves onto seperate branches?
>
> Thanks for yor help.
> Martin
>
>
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