ROOT crashes during scatter plot

Wolfgang Korsch (wkorsch@server1.pa.uky.edu)
Tue, 12 May 1998 17:35:53 -0400


Hi Rooters,
I have a large sample of data (>1.5e6 evts) and I want to generate
scatter plots. Using the command

root> ntuple.Draw("y:x");

works fine, but displays only the first (20,000 ?) events. That's
ok, then I do

root> ntuple.SetEstimate(1500000);
root> ntuple.Draw("y:x");

and I get either this error

----------------
Error in <RootX11IOError>: fatal X11 error (connection to server lost?!)

**** Save data and exit application ****
---------------

or this error

--------------
*** Break *** write on a pipe with no one to read it
Error in <RootX11IOError>: fatal X11 error (connection to server lost?!)

**** Save data and exit application ****
-------------

Then I have to quit ROOT. I have not gone through exercise
when which error appears.
These error messages do not appear in 1D histograms, i.e

root> ntuple.SetEstimate(1500000);
root> ntuple.Draw("x");
root> ntuple.Draw("y");

works fine.

Now I tried to find the "bad" event and I then I did the following:

root> ntuple.SetEstimate(#_of_bad_event);
root> ntuple.Draw("y:x");

Then I get the following error:

-----------------------
Error in <RootX11Error>: BadLength (poly request too large or internal Xlib
length error) (XID: 0)
----------------------

The ROOT freezes and I have to kill the process.

I cannot see anything wrong with the event.

Any ideas? I run DU 4.0A and ROOT 2.00/05

Thanks.

Wolfgang