Re: [ROOT] TTree 2-d plot problem

From: Rene Brun (Rene.Brun@cern.ch)
Date: Sat Aug 17 2002 - 11:47:05 MEST


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
> =======================================================================
>   Fermilab MS-220                            Phone: (+1) 630 840 8378
>   P.O. Box 500                               Fax:   (+1) 630 840 6039
>   Batavia, IL 60510 USA
> 
> 



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