TTree::Draw() with expression and dynamic array problem

From: stefan kluth (skluth@mh1.lbl.gov)
Date: Wed Aug 19 1998 - 19:53:29 MEST 

Hi,

I have a tree with dynamic arrays of floats as branches and a basic float
branch. I would like to plot a simple expression involving a dynamic
array, but it doesn't work. Here is an example root session:

  *******************************************
  *                                         *
  *        W E L C O M E  to  R O O T       *
  *                                         *
  *   Version   2.00/10      30 July 1998   *
  *                                         *
  *  You are welcome to visit our Web site  *
  *          http://root.cern.ch            *
  *                                         *
  *******************************************

CINT/ROOT C/C++ Interpreter version 5.13.66, July 24 1998
Type ? for help. Commands must be C++ statements.
Enclose multiple statements between { }.
root [0] TFile f1("framework.root"); 
root [1] ntp1->Print();             
******************************************************************************
*Tree    :ntp1      : yflips
*
*Entries :      100 : Total  Size =     44566 bytes  File  Size =
44566 *
*        :          : Tree compression factor =   1.00
*
******************************************************************************
*Branch  :ievent    : ievent/I
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :sume      : sume/F
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :njets     : njets/I
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :JE0yf     : JE0yf[njets]/F
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :Pyf       : Pyf[njets]/F
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :P0yf      : P0yf[njets]/F
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :Eyf       : Eyf[njets]/F
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :Dyf       : Dyf[njets]/F
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :Gyf       : Gyf[njets]/F
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :Lyf       : Lyf[njets]/F
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
*Branch  :E0yf      : E0yf[njets]/F
*
*Entries :      100 : Total  Size =         0 bytes  File Size  =
0 *
*Baskets :        0 : Basket Size =      8000 bytes  Compression=   1.00
*
*............................................................................*
root [2] ntp1->Draw("njets/sume");  
Warning in <MakeDefCanvas>: creating a default canvas with name c1
root [3] ntp1->Draw("Lyf[1]/sume"); 


Error: No symbol ntp1->Draw("Lyf[1]/sume") in current scope
FILE:/tmp/faaaazuca LINE:1
*** Interpreter error recovered ***
root [5] ntp1->Draw("njets/sume"); 
Error: No symbol ntp1->Draw("njets/sume") in current scope
FILE:/tmp/gaaaazuca LINE:1
*** Interpreter error recovered ***


The first command "ntp1->Draw("njets/sume");" works as expected. The
second command "ntp1->Draw("Lyf[1]/sume");" cocks up the interpreter, such
that even the first command does not work anymore. 

Any ideas? cheers, Stefan


---Stefan Kluth---------------Lynen Fellow----------------|\--|\-------
-  LBNL, MS 50A 2160       -  phone:  +1 510 495 2376  -  |/  |/      -
-  1 Cyclotron Rd.         -  fax:    +1 510 495 2957  -  |\/\|\/\|'  -
---Berkeley, CA94720, USA-----e-mail: SKluth@lbl.gov------|/\/|/\/|----

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