overlay::Overlay Class Reference

Overlay processor allows to overlay an event with background events from additional LCIO files based on different criteria. More...

#include <Overlay.h>

Inheritance diagram for overlay::Overlay:

Public Member Functions
virtual marlin::Processor *	newProcessor ()
virtual const std::string &	name () const
virtual void	modifyEvent (EVENT::LCEvent *evt)
virtual void	init ()
	Called at the begin of the job before anything is read. More...
virtual void	processRunHeader (LCRunHeader *run)
	Called for every run.
virtual void	check (EVENT::LCEvent *evt)
	Called for every event - the working horse.
virtual void	end ()
	Called after data processing for clean up.

Protected Member Functions
LCEvent *	readNextEvent ()
	Helper method.

Protected Attributes
StringVec	_fileNames
	Input file names.
int	_numOverlay
double	_expBG
bool	_runOverlay
int	_nSkipEventsRandom
StringVec	_colVec
std::map< std::string, std::string >	_colMap
IO::LCReader *	_lcReader
EVENT::LCEvent *	_overlayEvent
int	_activeRunNumber
int	_nRun
int	_nEvt
int	_nOverlayEvt
IntVec	_events

Detailed Description

Overlay processor allows to overlay an event with background events from additional LCIO files based on different criteria.

A typical use case would be the overlay of gamma gamma -> hadrons background events with a number drawn from a poissonian distribution with a given mean 'expBG' (NumberOverlayEvents=0). Best to specfiy only one input file as then direct access in LCIO is used.

See Merger.cc for the collection types that can be merged.

Author

N. Chiapolini, DESY

F. Gaede, DESY

Version

Id:

Overlay.h 851 2012-09-11 09:52:37Z gaede

Parameters

InputFileNames	(StringVec) The names (with absolute or relative pathes) of the files from which the background should be read. Multiple files can be given by a white spaces separated list or by setting this parameter multiple times. If the end of the last file is reached, before all events have been processed, a warning will be printed and reading restarted with the first file. NB: if only one file is given direct access is used - this is much faster (and thus preferred)
CollectionMap	(StringVec) Pairs of collection names. The input collection (given first) will be merged into the output collection. If the output collection does not exist, it will be created. It is recommended to set this parameter once for each collection pair. If this parameter is not set, all collections with the same name and type will be merged.
NumberOverlayEvents	(int) Fixed number of background events that should be added to each physics event. (default 0)
expBG	(double) If this value is set, a random number of background will be added to each physics event. The Random numbers will be thrown according to a Poisson distribution with this expectation value. If set, NumberOverlayEvents will be added to the random number.
runOverlay	(bool) If true, NumberOverlayEvents and expBG will be ignored. Instead one run of background events will be added to each physics event.
NSkipEventsRandom	Maximum number of events to skip between overlayd events (choosen from flat intervall [0,NSkipEventsRandom] ) used if more than one inout file given and skipNEvent is used

Member Function Documentation

void overlay::Overlay::init ( )

virtual

Called at the begin of the job before anything is read.

Use to initialize the processor, e.g. book histograms.

References _fileNames.

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The documentation for this class was generated from the following files:

• Overlay.h
• Overlay.cc