Re: interactive handling of TClonesArray (ROOT 1.01/07)

Pasha Murat (murat@cdfsga.fnal.gov)
Sat, 5 Jul 1997 12:53:58 GMT

Rene Brun writes:
>
> You can access the Track data interactively. That is precisely the intention
> of the root/test/Event example you are quoting.
> This program writes a Tree with a TClonesArray.
> In an interactive session, you can then access any element of the array
> with statements like:
> Root > TFile f("Event.root");
> Root > T.Draw("fPx"); where fPx is a data member of the class Track
>

Dear Rene,

I apologize for being a little bit impatient. What I mean is that given an event
it doesn't seem possible to calculate an effective mass of 2 tracks or to find
a track in event with highest Pt, in other words - it doesn't seem possible to
get a pointer to a track defined in user's code. This is a problem.
The option you mentioned - looping (inside ROOT, not inside user's code) over all
the tracks - doesn't solve it.

Regards, Pasha.