Re: [ROOT] multiple arrays in TTree::Draw

From: Suzanne Panacek (spanacek@fnal.gov)
Date: Wed Jun 20 2001 - 17:27:39 MEST


Hi,
To be more specific, in the latest Users Guide (v3.1a) at
http://root.cern.ch/root/RootDoc.html
you can find 35 examples of the TTree::Draw command. Many of the examples
are covering arrays.

These are in the chapter on Trees on page 249 (v3.1b) and pg 243 (v3.1a).

Suzanne
----- Original Message -----
From: "Rene Brun" <Rene.Brun@cern.ch>
To: "Volker Buescher" <buescher@fnal.gov>
Cc: <roottalk@pcroot.cern.ch>
Sent: Wednesday, June 20, 2001 10:01 AM
Subject: Re: [ROOT] multiple arrays in TTree::Draw


> Hi Volker,
> What you want is already there in Root version 3.01.
> There are many examples of this type in the documentation.
>
> Rene Brun
>
> On Wed, 20 Jun 2001, Volker Buescher wrote:
>
> >
> > Hi All,
> >
> > I keep running into an apparent limitation of the Draw method of TTree,
> > and I would appreciate very much any advice on whether this is possible
in
> > root or whether it could be added in future versions. Here is an example
> > of what I'm trying to do:
> > I have two branches, each with several variable length arrays,
> > e.g. arrays mc_pt[nmc], mc_eta[nmc] in one branch and reco_pt[nreco],
> > reco_eta[nreco] in the other branch. Now I'd like to use Draw() on the
> > command line to plot for each event a) every entry in mc_pt versus every
> > entry in reco_pt and b) same as in a) but apply cuts like
> > "abs(mc_eta-reco_eta)<0.1", such that only those pairs of mc_pt/reco_pt
> > are plotted, for which that condition is true.
> >
> > As far as I understand, root only allows to plot pairs
> >
> > (mc_pt[0],reco_pt[0])
> > (mc_pt[1],reco_pt[1])
> > (mc_pt[2],reco_pt[2])
> > ...
> >
> > rather than all possible combinations - did I overlook something? Is
there
> > a way to do this without the inconvenience of using Loop()? If not,
> > would it be possible to add this feature?
> >
> > Thanks!
> > Volker
> >
>
>



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