Re: [ROOT] TTree 2-d plot problem

From: Peter Shanahan (shanahan@fnal.gov)
Date: Wed Aug 21 2002 - 18:55:15 MEST


Hi Rene,

   The root file location is in my previous message to you.

   The root version is 3.03/07.  I made the tree within our minos
version of root, and get the same bad result whether I analyse with
the minos version or root proper.  The draw command that doesn't work
is simply

  T->Draw("adc:tframe")

  It immediately sets the X axis from 0. to 50., and depending on the
machine, the root session may or may not seize.

  On the contrary,

  T->Draw("tframe") works just fins, with the correct range of about
(0.,100.)

  Many thanks,

Peter Shanahan

On Sat, 17 Aug 2002, Rene Brun wrote:

> Hi Peter,
>
> Could you put your file in some public area/web server
> and let me know the address as well as the TTree::Draw
> command that shows this problem?
> Which version of Root are you using?
>
> Rene Brun
>
>
> On Fri, 16 Aug 2002, Peter Shanahan wrote:
>
> > Dear Root Experts,
> >
> >      I am having trouble with a simple, 1 branch TTree.  Since the problem
> > doesn't occur for smaller TTrees (less than 5-10 Mb), the debugging loop
> > is very slow.
> >
> >      So, my first and main question is, is there a way to check the sanity
> > of a tree, beyond TTree::Print()?
> >
> >      My second question is, does the odd behavior described below ring
> > a bell with anyone?  Is there something about how TTree::Draw() gets
> > variable ranges for 2-D plots that offers a clue to what I might be
> > doing wrong?
> >
> >      I write the tree to a file, close the file, and open it in a
> > completely new session, which knows nothing of the macro I used to create
> > and fill the tree.  TTree::Print() looks fine.  1-D plots are fine, with
> > or without cuts on other variables.   TTree::Scan() is also fine.
> >
> >      When I try to do a 2-D plot, however, axes are drawn almost
> > immediately, with too small a range for one of the variables, in at
> > least one case.  (That case involves a variable that is monotonic in
> > entry number).  The memory usage of the root process goes to 3 times the
> > normal level, and it takes much, much longer to draw than a 1-D plot.
> >
> >      Any ideas?  Many Thanks,
> >
> > Peter Shanahan



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