Hi Rooters, I have written a class to write (for now) a simple ntuple (TNtuple) as an summary of the data-aqcuisition I am running. Thinking there was a bug on my side, I in the end printed every entry to go into the ntuple on a small bit of data. It turned out that I could plot the values expected. Running the same again on a big amount of data, the ntuple got filled as I expected, but the TTree->Draw() failed to draw the correct distribution of data! As an illustration: STNtuple->Draw("preamp_bias") -> this draws a single peak of hight 11648 at x = 211.6 (nentries = 23296!) STNtuple->Draw("preamp_bias","preamp_bias < 200") -> this draws a single peak of hight 11648 at x = 147.2 Of course I would like the first command to draw both peaks! I am using ROOT version 2.21/08 on linux. Many thanks for any useful hints on how to solve this, Simon Peeters. -- NIKHEF, National Institute for Nuclear and High Energy Physics Kruislaan 409, office H-044 Tel:(+31-20-592) 5140 P.O. Box 41882, 1009 DB Amsterdam (NL) Fax:(+31-20-592) 5155 CERN, building 40, office 2-D06 Tel:(+41-22-76) 71157
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