(no subject)

Rene Brun (Rene.Brun@cern.ch)
Fri, 18 Dec 1998 14:33:40 +0100

vdschaaf wrote:
>
> Hi,
>
> I've a problem with TTree's.
> If I have a big tree (say 200 Mb) and want to access ntuple data in it, I
> typically say
>
> f=new TFile(".....");
> TTree *ntuple = (TTree*)gDirectory->Get("ntuple");
> int nevent=ntuple->GetEntries();
> for (i=0; i<nevent; i++) {
> ntuple->GetEvent(i);
> ......
> }
>
> but after the Get, it starts to load 200 Mb of data into memory......That won't
> work. Is there another method to access the data without loading everything
> into memory first?

I suspect something wrong when you wrote your TTree.
Could yous end me the output of
ntuple->Print();
added immediatly after Get("ntuple")

Rene Brun