Hi Roy,
Currentlty TTree::MakeClass does not read entries at all.
The min/max count for each array of a branch is stored in the branch
header itself. Doing what you propose would imply reading the
Tree/Branch headers from all the files. Could be done.
Any volunteer to implement this logic ?
Rene Brun
On Thu, 22 Aug 2002, Roy Lee wrote:
> Hi,
>
> I noticed a problem when calling the MakeClass() method for a TChain when
> a tree contains TClonesArray objects. Here are the command I issue:
>
> TChain reco("reco");
> reco->Add("eventsr1.root");
> reco->Add("eventsr2.root");
> reco->MakeClass();
>
> If I look in the output file reco.h, I see at the top:
>
> //////////////////////////////////////////////////////////
> // This class has been automatically generated
> // (Thu Aug 22 11:49:49 2002 by ROOT version3.03/06)
> // from TChain reco/
> //////////////////////////////////////////////////////////
>
>
> #ifndef reco_h
> #define reco_h
>
> #include <TROOT.h>
> #include <TChain.h>
> #include <TFile.h>
> const Int_t kMaxvetodgt = 104;
> const Int_t kMaxstp = 2200;
> const Int_t kMaxslc = 1;
> const Int_t kMaxtrk = 3;
> const Int_t kMaxshw = 1;
> const Int_t kMaxevt = 2;
>
> These kMax* variables define the maximum number of entries each
> TClonesArray object contains. What I noticed is that these maximums seem
> to be valid only for the first tree added in the chain. In other words,
> if kMaxvetodgt is 200 for eventsr2.root/reco, it totally ignores that and
> puts the value for eventsr1.root/reco (since it was the first tree to be
> added).
>
> Is this an intended feature? It seems logical to have these kMax* values
> calculated over all trees added to a chain.
>
> Roy
>
> ------------------------------------------------------------------------------
> Roy Lee / rlee@physics.harvard.edu / Department of Physics, Harvard University
>
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