####################################################
#
#  package Overlay provides code for event overlay
#  with Marlin
#
#
#  F.Gaede, 08/2007
####################################################

 The Overlay processor can be used to overlay background 
 events from an additonal set of LCIO files in a Marlin job.

 It requires Marlin v01-00 or higher.

 For details see ./doc/Overlay.pdf and the doxygen API doc.

The JoinEvents processor can be used to join events on a collection basis,
i.e events from an additional input file  are read and all 
collections are added to the current event (provided they have a 
name that is different from all collections in the current event).



 Build instructions:
 -------------------

   . path_to_ilcsoft_installation/v01-XX/init_ilcsoft.sh

   mkdir build 
   cd build 

   cmake -C $ILCSOFT/ILCSoft.cmake ..

   make install


 or use the ilcinstall script to install together with the ilcsoft release.




 Versions:
 ---------

 -----------
| v00-11-01 |
 -----------

    - bug fixes:

        - OverlayTiming.cc: fixed correct particle time for background MCParticles based on their BX (M. Killenberg)

        - FPCCDOverlayBX.cc: fixed gcc 4.5 issue (D. Kamai)

 ----------
|  v00-11  |
 ----------

    - New processor (OverlayEvents) to merge a number of events in a LCIO file into one event.

    - First version of background overlay processor for FPCCD (FPCCDOverlayBX)

    - Added dependency to Marlinutil (needed by FPCCOverlay ) 


 -----------
| v00-10-00 |
 -----------

    - Several code improvements and corrections to OverlayTiming processor (J. Marshall, A. Sailer)

        - Delete Calorimeter hits that are not added to the collection

        - Timing window is extended so that it runs from -0.25ns to numeric_limits<float>::max() ns if an unrecognized collection name is specified.

        - Time of flight function is now inline, its use of pow() has been removed and any unnecessary calls to this function have also gone.

        - Made MCParticle collection name configurable

        - Setting "lcioDetailedShowerMode false" is now default (see http://indico.cern.ch/conferenceDisplay.py?confId=107327),
            so calls to "CalorimeterHit->getPDGCont(j)" do not make sense. Remove these calls to avoid logic based on uninitialized variables.
        
        - Clear DestMap at the end of ModifyEvent, do not only run this in Check() as this can be suppressed.

        - Use one destMap per collection to avoid adding calorimeterHits from one subDetector to a different.

        - Copy MCParticles for physics event into a new collection.

        - Tidied-up code with an emphasis on removing risk posed by uninitialized variables e.g.
            create stack pointers within for loops, rather than re-using single pointer declared outside loop, etc.
            Removed unused member variables, tidied header file includes, improved const-correctness and removed tab characters.
            Use of parentheses to clarify logic in if statements


 -----------
| v00-09-01 |
 -----------

    - Fixed address memory management issues associated with removing elements from an LCIO collection. When an element is removed, it is the user's
        responsibility to take care of the memory management, e.g. by deleting the object or by adding it to another collection in the LCEvent.
        Cosmetic change: added a typedef for "std::map<long long, SimCalorimeterHit*>" to improve readability. (J. Marshall)

    - Make OverlayTiming runable without specifying files. Do not run overlay loop if nothing is supposed to be overlaid. (A. Sailer)

    - Modified file handling, minor improvements (P. Shade)

 _______ 
|v00-09 |   
 -------
     - minor modifications
        -- timing window start time set to small negative value
        -- simplified cmake files


 _______ 
|v00-08 |   
 -------
     - added new processor OverlayTimimg (P.Schade)
       for CLIC related bg studies


 __________ 
|v00-07-04 |   
 ----------
       - same as v00-07-03 with fix for build on MacOS (streamlog)

 __________ 
|v00-07-03 |   
 ----------
   - minor fixes and improvements 

        - CMakeLists.txt: 
          - BUILD_32BIT_COMPATIBLE set per default to OFF
          - added exclude pattern for .svn dirs
          - added ctest

        - fixed doxygen documentation

 __________ 
|v00-07-01 |   
 ----------
   - bug fix: incorrect library version numbers

 _______ 
|v00-07 |   
 -------
   - added overlay of many bunch crossings for TPC hits, 
     properly shifted in z according to time structure.
   - introduced random rotation of TPC hits in azimuthal angle    
   - added LCIO::THBIT_MOMENTUM for newly created TPC collections
   - MCParticle pointer set to 0 for non-VXD SimTrackerhits
   - bug fix: nVXDBX for nVXDHits

 __________ 
|v00-06-01 |   
 ----------
   - bug fix for overlaying exactly 1 BX for the VXD 


 _______ 
|v00-06 |   
 -------
   - experimental version of overlaying background for many bunch crossings

 ______ 
|v00-04|   
 ------
    - use optional direct access in LCIO - requires v01-11 or higher
 ______ 
|v00-03|   
 ------
    - made gcc 4.3 compliant
    - made cmake 2.6 compliant
    - added 32 bit compatibility build option

 ______ 
|v00-02|   
 ------
     - added JoinEvents processor      
         (requires LCIO v01-08-05 or higher )

       recommended Marlin v00-09-10, LCIO v01-09

 ______ 
|v00-01|   initial version
 ------