Created: Rainer Bartoldus, Feb 21 2004.
                                        (Updated: Apr 7, 2006)


  README on how to skim events from an xtc file
  ---------------------------------------------
  
  Skimming xtc files is actually very easy.  There is a wrapper script
  to run the Level 3 skim application called:
  
    runL3TSkimApp
  
  All you need to do is to set your path to a recent release.  Unless
  you know better, the 'newest' link should always be a good choice.
  So,
  
    $ srtpath newest
    <return>
    <return>
  
  Then you need to set your OO_FD_BOOT file to get access to the
  configuration database. Typically, you would do:
  
    $ ambientboot
  
  (If you see an error complaining about 'gmake database.config', you
  can just ignore that.)
  
  [** Temporary note: If you are working against a pre-18.6.3 or early
    20-series release (the run, not your working release),
   
    checkout the following package:

      L3Trigger V00-13-07

    and rebuild L3Trigger.binscripts

   (Or, you can switch to the Objectivity (instead ofthe ROOT) implementation,
    by unsetting CFG_DEFAULT_IMPL parameter:

      $ unset CFG_DEFAULT_IMPL 
    or
      $ unsetenv CFG_DEFAULT_IMPL
   ) ]


  Next, run the application like this:
  
    $ runL3TSkimApp -f <xtc file> [-n <number of events>] [<tcl file>]
  
  The -n option and the <tcl file> argument are optional. 
  
  If you don't specify a tcl file, the application will just skim the
  number of events given by the -n option.  (Or every event if there
  is no -n.)
  
  The tcl file allows you to skim on a particular trigger bit, or a
  set of trigger bits.  It should look something like this:
  
    #
    # L3OutCyclic1.tcl
    #
    # Skims cyclic trigger events from an xtc file.
    #
    
    sourceFoundFile L3Trigger/L3TSkimApp.tcl
    
    module talk TrgOepOutputLineFilter
      linesOn set "L3OutCyclic1"
    exit
  
  Look around for existing tcl files in this directory.  If you don't
  find one, just start from a copy of this example and modify it to
  your needs.

  In addition to the OepOutputLines, you can talk to one or more of
  the following modules:
  
    TrgFctLineFilter
    TrgGltLineFilter
    TrgL3InputFilter
    TrgL3ScriptFlagFilter
    TrgOepInputLineFilter
    TrgOepOutputLineFilter

  [ FYI:
      L1 lines           (from GLT/FCT)
      L3 input lines     (OR of L1 lines)
      L3 script flags    (result of L3 algorithms and filters)
      L3 output lines    (OR/VETO of scripts)
       = OEP input lines
      OEP output lines   (after prescaling)
  ]
  
  For more information on what these are, take a look at the
  TrgConfig(5) man page.

  Happy skimming.

  -- Rainer