[ROOT] Strange ntupe behavior.

From: Ed Oltman (eoltman@imago.com)
Date: Thu Sep 05 2002 - 20:58:26 MEST 

Hello,
 I have a root file with a single ntuple created with:

    TFile *f = new TFile("test.root","RECREATE");
    TNtuple *nt = new TNtuple("nt","ff","x:y:z:xd:yd:zd:s");
                 .
                 .
    for(int i=0;i<totInShell;i++)
    {
                 .
                 .
        nt->Fill((x,y,z,xd,yd,zd,s);
    }
    f->Write();
    f->Close();

I would be happy to send the root file - its 339 kBytes.   The file is
generated with a standalone application (Win2K + VC6.0)

I then open the ntuple in a normal root session:

    TFile *f = new TFile("test.root")

At the bottom of this not is result of nt->Print()

Here's the problem:  I can display any single branch with nt->Draw() EXCEPT
xd and yd.  IF I try these, root consumes all my cpu until I type ctrl-C.
However, I can do

    nt->Draw("xd:x") or nt->Draw("yd:xd") etc...

The only failures I have are nt->Draw("xd") and nt->Draw("yd").  Same
failure occurs if I use a TBrowser object to inspect the ntuple.

Note: I can create a 1D histogram and project xd onto it

    TH1F *pxd = new TH1F("pxd","xd",100,-25.,25.)
    nt->Project("pxd","xd");
    pxd->Draw()

and it works fine.  I have the problem in both 3.02/7 and 3.03/8.
(stand-alone application linked with same version as root.exe)

Any ideas what might be wrong?

Thanks,
Ed Oltman


here is nt->Print()

****************************************************************************
**
*Tree    :nt        : ff
*
*Entries :    30664 : Total =          748011 bytes  File  Size =     331425
*
*        :          : Tree compression factor =   2.63
*
****************************************************************************
**
*Br    0 :x         :
*
*Entries :    30664 : Total  Size=      95994 bytes  File Size  =      40248
*
*Baskets :        3 : Basket Size=      32000 bytes  Compression=   2.39
*
*...........................................................................
.*
*Br    1 :y         :
*
*Entries :    30664 : Total  Size=      95994 bytes  File Size  =      41533
*
*Baskets :        3 : Basket Size=      32000 bytes  Compression=   2.31
*
*...........................................................................
.*
*Br    2 :z         :
*
*Entries :    30664 : Total  Size=      95994 bytes  File Size  =      31161
*
*Baskets :        3 : Basket Size=      32000 bytes  Compression=   3.08
*
*...........................................................................
.*
*Br    3 :xd        :
*
*Entries :    30664 : Total  Size=      95997 bytes  File Size  =      55843
*
*Baskets :        3 : Basket Size=      32000 bytes  Compression=   1.72
*
*...........................................................................
.*
*Br    4 :yd        :
*
*Entries :    30664 : Total  Size=      95997 bytes  File Size  =      55933
*
*Baskets :        3 : Basket Size=      32000 bytes  Compression=   1.72
*
*...........................................................................
.*
*Br    5 :zd        :
*
*Entries :    30664 : Total  Size=      95997 bytes  File Size  =      30069
*
*Baskets :        3 : Basket Size=      32000 bytes  Compression=   3.19
*
*...........................................................................
.*
*Br    6 :s         :
*
*Entries :    30664 : Total  Size=      95994 bytes  File Size  =        594
*
*Baskets :        3 : Basket Size=      32000 bytes  Compression= 161.61
*

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