Re: upcoming updates in BRAT

From: Christian Holm Christensen (cholm@hehi03.nbi.dk)
Date: Thu May 03 2001 - 05:35:33 EDT

  • Next message: Christian Holm Christensen: "Re: BRAT changes - mult code and build system"

    Hi Flemming, 
    
    On Wed, 2 May 2001 20:47:43 -0400
    "Flemming Videbaek" <videbaek@sgs1.hirg.bnl.gov> wrote
    concerning ": upcoming updates in BRAT":
    > As part of the process of updating and upgrading various tracking to
    > accomodate a more general approach I have changed (after
    > consultation with the local working groups) code and methods in
    > tracking classes. The changes has yet to be commiteed 
    > this is an announchement, and comments are appreciated.
    > 
    > - BrModuleMatchTrack class
    > 
    > ---- Extensive rewrite to simplify geometry handling. Replaced max
    >      array classes with STL <vector> implementation. 
    
    Uh.  Why STL vector<..>? I believe that recent experience from the
    ROOT team clearily shows that TCollection and derived classes, are
    much better (i.e., faster, safer) than the STL counter parts.  From
    the release note of ROOT 3.00/06: 
    
      New test suite and benchmark bench.cxx. This test program compares the
      I/O performance obtained with STL vector of objects or pointers to
      objects versus the native ROOT collection class TClonesArray.
      Trees in compression and non compression mode are created for each
      of the following cases:
        -vector<THit>
        -vector<THit*>
        -TClonesArray(TObjHit) in no split mode
        -TClonesArray(TObjHit) in split mode
    
    I've run the benchmark test, and it clearly shows that TClonesArray is
    far superior to vector<...>.  I've attached the output. 
    
    My own experience also suggets that STL containers are not as neat and
    easy to handle as ROOT's counter parts. 
    
    Yours, 
    
    Christian  -----------------------------------------------------------
    Holm Christensen                             Phone:  (+45) 35 35 96 91 
      Sankt Hansgade 23, 1. th.                  Office: (+45) 353  25 305 
      DK-2200 Copenhagen N                       Web:    www.nbi.dk/~cholm    
      Denmark                                    Email:       cholm@nbi.dk
    
    
    
    



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