Re: [ROOT] problem with tree->Draw()

From: Rene Brun (Rene.Brun@cern.ch)
Date: Fri Sep 01 2000 - 09:07:34 MEST


Hi HP,
When looking at the file you sent to me yesterday, I see that your Tree
attributes have very large positive and negative values ( > 1e33).
If one draws one of this attributes, the axis painting routine crashes
in the particular range of values that are in your file. This is a consequence
of the change from single to double precision in version 2.25.
I have fixed this problem in our development version.
Thanks for reporting this case.

Rene Brun

HP Wei wrote:
> 
> 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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