[ROOT] problem with tree->Draw()

From: HP Wei (hp@rentec.com)
Date: Fri Sep 01 2000 - 01:40:34 MEST


Hi rooters,
   I encounter a strange behavior for a particular
   .root file.
   This file has one tree with three branches, two
   Int_t's and one Double_t.
   The number of entries is 1089840.
   
   Machine: Sun Solaris
   ROOT/Cint 5.25.0, and 5.14.40
   
   In Root/cint, 
   I type: TFile f("file.root");
   then check the data by doing:
   T->Scan("capt", "ntic==0");
   T->Scan("capt", "ntic==1");
   T->Scan("capt", "ntic==2");
   T->Scan("capt", "ntic==3");
   
   Each one of the Scan produces 120 entries which are
   all ok.
   
   Now I do:
   T->Draw("capt", "ntic==0", "goff");
   T->Draw("capt", "ntic==1", "goff");
   T->Draw("capt", "ntic==2", "goff");
   The third line results in a frozen screen !!!
   I need to type Control_C to get out.
   AFter getting out, I type T.
   It says: NO Symbol T in current scope...
   
   Furthermore,  let me represent
   a sequence of T->Draw() commands as
   [n1, n2, n3 ...]
   which means:
   T->Draw("capt", "ntic==n1", "goff");
   T->Draw("capt", "ntic==n2", "goff");
   etc..

   Using that notation, I find the following situations:
   [1 3 4 5 ] appears to be ok.
   [10 9 13 13 ] ok.
   [10 1 2] ----> freeze!
   [10 2] ---> freeze!
   [0 2] ---> freeze!
   [1 2] ---> freeze!
   [2 3 4 5 1 2] ---> freeze!!
   
   Since the data look fine as browsed by T->Scan(),
   I have no clue about what is going on.
   Any suggestion?   
   
HP



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