Replacement for TrackingTruthProducer in the new pileup mixing setup. More...

#include <TrackingTruthAccumulator.h>

Inheritance diagram for TrackingTruthAccumulator:

Classes
struct	OutputCollections

Public Member Functions
	TrackingTruthAccumulator (const edm::ParameterSet &config, edm::one::EDProducerBase &mixMod, edm::ConsumesCollector &iC)

Public Member Functions inherited from DigiAccumulatorMixMod
virtual void	beginLuminosityBlock (edm::LuminosityBlock const &lumi, edm::EventSetup const &setup)

virtual void	beginRun (edm::Run const &run, edm::EventSetup const &setup)

	DigiAccumulatorMixMod ()

virtual void	endLuminosityBlock (edm::LuminosityBlock const &lumi, edm::EventSetup const &setup)

virtual void	endRun (edm::Run const &run, edm::EventSetup const &setup)

virtual void	finalizeBunchCrossing (edm::Event &event, edm::EventSetup const &setup, int bunchCrossing)

virtual PileupMixingContent *	getEventPileupInfo ()

virtual void	initializeBunchCrossing (edm::Event const &event, edm::EventSetup const &setup, int bunchCrossing)

virtual void	StorePileupInformation (std::vector< int > &numInteractionList, std::vector< int > &bunchCrossingList, std::vector< float > &TrueInteractionList)

virtual	~DigiAccumulatorMixMod ()

Private Member Functions
virtual void	accumulate (const edm::Event &event, const edm::EventSetup &setup)

virtual void	accumulate (const PileUpEventPrincipal &event, const edm::EventSetup &setup, edm::StreamID const &)

template<class T >
void	accumulateEvent (const T &event, const edm::EventSetup &setup)
	Both forms of accumulate() delegate to this templated method. More...

template<class T >
void	fillSimHits (std::vector< const PSimHit * > &returnValue, const T &event, const edm::EventSetup &setup)
	Fills the supplied vector with pointers to the SimHits, checking for bad modules if required. More...

virtual void	finalizeEvent (edm::Event &event, const edm::EventSetup &setup)

virtual void	initializeEvent (const edm::Event &event, const edm::EventSetup &setup)

Private Attributes
const bool	addAncestors_
	Whether or not to add the full parentage of any TrackingParticle that is inserted in the collection. More...

bool	allowDifferentProcessTypeForDifferentDetectors_
	When counting hits, allows hits in different detectors to have a different process type. More...

bool	chargedOnly_
	Uses the same config as selector_, but can be used to drop out early since selector_ requires the TrackingParticle to be created first. More...

std::vector< edm::InputTag >	collectionTags_

const bool	createMergedCollection_

const bool	createUnmergedCollection_
	If bremsstrahlung merging, whether to also add the unmerged collection to the event or not. More...

edm::InputTag	genParticleLabel_

const bool	ignoreTracksOutsideVolume_

const unsigned int	maximumPreviousBunchCrossing_

const unsigned int	maximumSubsequentBunchCrossing_

OutputCollections	mergedOutput_

const std::string	messageCategory_
	The message category used to send messages to MessageLogger. More...

const bool	removeDeadModules_
	As of 11/Feb/2013 this option hasn't been implemented yet. More...

TrackingParticleSelector	selector_

bool	selectorFlag_

bool	signalOnly_
	Uses the same config as selector_, but can be used to drop out early since selector_ requires the TrackingParticle to be created first. More...

const edm::InputTag	simTrackLabel_

const edm::InputTag	simVertexLabel_

OutputCollections	unmergedOutput_

const double	volumeRadius_

const double	volumeZ_

Detailed Description

Replacement for TrackingTruthProducer in the new pileup mixing setup.

The configuration parameters are:

Parameter name	Type	Description
volumeRadius	double	The volume radius in cm used if ignoreTracksOutsideVolume is true.
volumeZ	double	The volume z in cm used if ignoreTracksOutsideVolume is true.
ignoreTracksOutsideVolume	bool	If true, sim tracks that have a production vertex outside the volume specified by volumeRadius and volumeZ won't be turned into TrackingParticles. Doesn't make much difference to be honest, over a huge range of volume sizes so there must be a cut earlier in the simulation.
maximumPreviousBunchCrossing	unsigned int	Bunch crossings before this number (inclusive; use positive integer) won't be included. Setting to zero means only in-time.
maximumSubsequentBunchCrossing	unsigned int	Bunch crossings after this won't create any TrackingParticles.
createUnmergedCollection	bool	Whether to create the TrackingParticle collection without bremsstrahlung merged.
createMergedBremsstrahlung	bool	Whether to create the TrackingParticle collection with bremsstrahlung merged. At least one of createUnmergedCollection or createMergedBremsstrahlung should be true otherwise nothing will be produced.
alwaysAddAncestors	bool	If a sim track passes selection and is turned into a TrackingParticle, all of it's parents will also be created even if they fail the selection. This was the default behaviour for the old TrackingParticleProducer.
removeDeadModules	bool	Hasn't been implemented yet (as of 22/May/2013).
simTrackCollection	edm::InputTag	The input SimTrack collection
simVertexCollection	edm::InputTag	The input SimVerted collection
simHitCollections	edm::ParameterSet	A ParameterSet of vectors of InputTags that are the input PSimHits
genParticleCollection	edm::InputTag	The input reco::GenParticle collection. Note that there's a difference between reco::GenParticle and HepMC::GenParticle; the old TrackingTruthProducer used to use HepMC::GenParticle.
allowDifferentSimHitProcesses	bool	Should be false for FullSim and true for FastSim. There's more documentation in the code if you're really interested.
select	edm::ParameterSet	A ParameterSet used to configure a TrackingParticleSelector. If the TrackingParticle doesn't pass this selector then it's not added to the output.

Author: Mark Grimes (mark..nosp@m.grim.nosp@m.es@br.nosp@m.isto.nosp@m.l.ac..nosp@m.uk)

Date: 11/Oct/2012

Definition at line 68 of file TrackingTruthAccumulator.h.

Constructor & Destructor Documentation

TrackingTruthAccumulator::TrackingTruthAccumulator	(	const edm::ParameterSet &	config,
		edm::one::EDProducerBase &	mixMod,
		edm::ConsumesCollector &	iC
	)

explicit

Definition at line 217 of file TrackingTruthAccumulator.cc.

References chargedOnly_, collectionTags_, edm::ConsumesCollector::consumes(), createMergedCollection_, createUnmergedCollection_, edm::ParameterSet::exists(), genParticleLabel_, edm::ParameterSet::getParameter(), edm::ParameterSet::getParameterNames(), edm::ParameterSet::getParameterSet(), messageCategory_, selector_, selectorFlag_, signalOnly_, simTrackLabel_, simVertexLabel_, and o2o::tags.

                                                                                                                                           :
         messageCategory_("TrackingTruthAccumulator"),
         volumeRadius_( config.getParameter<double>("volumeRadius") ),
         volumeZ_( config.getParameter<double>("volumeZ") ),
         ignoreTracksOutsideVolume_( config.getParameter<bool>("ignoreTracksOutsideVolume") ),
         maximumPreviousBunchCrossing_( config.getParameter<unsigned int>("maximumPreviousBunchCrossing") ),
         maximumSubsequentBunchCrossing_( config.getParameter<unsigned int>("maximumSubsequentBunchCrossing") ),
         createUnmergedCollection_( config.getParameter<bool>("createUnmergedCollection") ),
         createMergedCollection_(config.getParameter<bool>("createMergedBremsstrahlung") ),
         addAncestors_( config.getParameter<bool>("alwaysAddAncestors") ),
         removeDeadModules_( config.getParameter<bool>("removeDeadModules") ),
         simTrackLabel_( config.getParameter<edm::InputTag>("simTrackCollection") ),
         simVertexLabel_( config.getParameter<edm::InputTag>("simVertexCollection") ),
         collectionTags_( ),
         genParticleLabel_( config.getParameter<edm::InputTag>("genParticleCollection") ),
         allowDifferentProcessTypeForDifferentDetectors_( config.getParameter<bool>("allowDifferentSimHitProcesses") )
 {
     //
     // Make sure at least one of the merged and unmerged collections have been set
     // to be created.
     //
     if( !createUnmergedCollection_ && !createMergedCollection_ )
         edm::LogError(messageCategory_) << "Both \"createUnmergedCollection\" and \"createMergedBremsstrahlung\" have been"
             << "set to false, which means no collections will be created";
 
     // Initialize selection for building TrackingParticles
     //
     if( config.exists( "select" ) )
     {
         edm::ParameterSet param=config.getParameter<edm::ParameterSet>("select");
         selector_=TrackingParticleSelector( param.getParameter<double>( "ptMinTP" ),
                 param.getParameter<double>( "minRapidityTP" ),
                 param.getParameter<double>( "maxRapidityTP" ),
                 param.getParameter<double>( "tipTP" ),
                 param.getParameter<double>( "lipTP" ),
                 param.getParameter<int>( "minHitTP" ),
                 param.getParameter<bool>( "signalOnlyTP" ),
                 param.getParameter<bool>( "chargedOnlyTP" ),
                 param.getParameter<bool>( "stableOnlyTP" ),
                 param.getParameter<std::vector<int> >("pdgIdTP") );
         selectorFlag_=true;
 
         // Also set these two variables, which are used to drop out early if the SimTrack doesn't conform.
         // The selector_ requires a full TrackingParticle object, but these two variables can veto things early.
         chargedOnly_=param.getParameter<bool>( "chargedOnlyTP" );
         signalOnly_=param.getParameter<bool>( "signalOnlyTP" );
     }
     else
     {
         selectorFlag_=false;
         chargedOnly_=false;
         signalOnly_=false;
     }
 
     //
     // Need to state what collections are going to be added to the event. This
     // depends on which of the merged and unmerged collections have been configured
     // to be created.
     //
     if( createUnmergedCollection_ )
     {
         mixMod.produces<TrackingVertexCollection>();
         mixMod.produces<TrackingParticleCollection>();
     }
 
     if( createMergedCollection_ )
     {
         mixMod.produces<TrackingParticleCollection>("MergedTrackTruth");
         mixMod.produces<TrackingVertexCollection>("MergedTrackTruth");
     }
 
         iC.consumes<std::vector<SimTrack> >(simTrackLabel_);
         iC.consumes<std::vector<SimVertex> >(simVertexLabel_);
         iC.consumes<std::vector<reco::GenParticle> >(genParticleLabel_);
         iC.consumes<std::vector<int> >(genParticleLabel_);
 
     // Fill the collection tags
         const edm::ParameterSet& simHitCollectionConfig=config.getParameterSet("simHitCollections");
     std::vector<std::string> parameterNames=simHitCollectionConfig.getParameterNames();
 
     for( const auto& parameterName : parameterNames )
     {
            std::vector<edm::InputTag> tags=simHitCollectionConfig.getParameter<std::vector<edm::InputTag> >(parameterName);
            collectionTags_.insert(collectionTags_.end(), tags.begin(), tags.end());
         }
 
     for( const auto& collectionTag : collectionTags_ ) {
       iC.consumes<std::vector<PSimHit> >(collectionTag);
         }
 
 }

Member Function Documentation

void TrackingTruthAccumulator::accumulate	(	const edm::Event &	event,
		const edm::EventSetup &	setup
	)

privatevirtual

Implements DigiAccumulatorMixMod.

Definition at line 328 of file TrackingTruthAccumulator.cc.

References accumulateEvent().

 {
     // Call the templated version that does the same for both signal and pileup events
     accumulateEvent( event, setup );
 }

void TrackingTruthAccumulator::accumulate	(	const PileUpEventPrincipal &	event,
		const edm::EventSetup &	setup,
		edm::StreamID const &
	)

privatevirtual

Implements DigiAccumulatorMixMod.

Definition at line 334 of file TrackingTruthAccumulator.cc.

References accumulateEvent(), PileUpEventPrincipal::bunchCrossing(), maximumPreviousBunchCrossing_, maximumSubsequentBunchCrossing_, and messageCategory_.

 {
     // If this bunch crossing is outside the user configured limit, don't do anything.
     if( event.bunchCrossing()>=-static_cast<int>(maximumPreviousBunchCrossing_) && event.bunchCrossing()<=static_cast<int>(maximumSubsequentBunchCrossing_) )
     {
         //edm::LogInfo(messageCategory_) << "Analysing pileup event for bunch crossing " << event.bunchCrossing();
         accumulateEvent( event, setup );
     }
     else edm::LogInfo(messageCategory_) << "Skipping pileup event for bunch crossing " << event.bunchCrossing();
 }

template<class T >

void TrackingTruthAccumulator::accumulateEvent	(	const T &	event,
		const edm::EventSetup &	setup
	)

private

Both forms of accumulate() delegate to this templated method.

Definition at line 368 of file TrackingTruthAccumulator.cc.

References addAncestors_, allowDifferentProcessTypeForDifferentDetectors_, EncodedEventId::bunchCrossing(), CoreSimTrack::charge(), chargedOnly_, createMergedCollection_, createUnmergedCollection_, EncodedEventId::event(), CoreSimTrack::eventId(), cppFunctionSkipper::exception, fillSimHits(), genParticleLabel_, ignoreTracksOutsideVolume_, cmsHarvester::index, mergedOutput_, NULL, CoreSimVertex::position(), selector_, selectorFlag_, signalOnly_, simTrackLabel_, simVertexLabel_, unmergedOutput_, volumeRadius_, and volumeZ_.

Referenced by accumulate().

 {
     //
     // Get the collections
     //
     edm::Handle<std::vector<SimTrack> > hSimTracks;
     edm::Handle<std::vector<SimVertex> > hSimVertices;
     edm::Handle< std::vector<reco::GenParticle> > hGenParticles;
     edm::Handle< std::vector<int> > hGenParticleIndices;
 
     event.getByLabel( simTrackLabel_, hSimTracks );
     event.getByLabel( simVertexLabel_, hSimVertices );
 
     try
     {
         event.getByLabel( genParticleLabel_, hGenParticles );
         event.getByLabel( genParticleLabel_, hGenParticleIndices );
     }
     catch( cms::Exception& exception )
     {
         //
         // The Monte Carlo is not always available, e.g. for pileup events. The information
         // is only used if it's available, but for some reason the PileUpEventPrincipal
         // wrapper throws an exception here rather than waiting to see if the handle is
         // used (as is the case for edm::Event). So I just want to catch this exception
         // and use the normal handle checking later on.
         //
     }
 
     // Run through the collections and work out the decay chain of each track/vertex. The
     // information in SimTrack and SimVertex only allows traversing upwards, but this will
     // allow traversal in both directions. This is required for things like grouping electrons
     // that bremsstrahlung as one TrackingParticle if "mergedBremsstrahlung" is set in the
     // config file.
     DecayChain decayChain( *hSimTracks, *hSimVertices );
 
     // I only want to create these collections if they're actually required
     std::auto_ptr< ::OutputCollectionWrapper> pUnmergedCollectionWrapper;
     std::auto_ptr< ::OutputCollectionWrapper> pMergedCollectionWrapper;
     if( createUnmergedCollection_ ) pUnmergedCollectionWrapper.reset( new ::OutputCollectionWrapper( decayChain, unmergedOutput_ ) );
     if( createMergedCollection_ ) pMergedCollectionWrapper.reset( new ::OutputCollectionWrapper( decayChain, mergedOutput_ ) );
 
     std::vector<const PSimHit*> simHitPointers;
     fillSimHits( simHitPointers, event, setup );
     TrackingParticleFactory objectFactory( decayChain, hGenParticles, hGenParticleIndices, simHitPointers, volumeRadius_, volumeZ_, allowDifferentProcessTypeForDifferentDetectors_ );
 
     // While I'm testing, perform some checks.
     // TODO - drop this call once I'm happy it works in all situations.
     //decayChain.integrityCheck();
 
     TrackingParticleSelector* pSelector=NULL;
     if( selectorFlag_ ) pSelector=&selector_;
 
     // Run over all of the SimTracks, but because I'm interested in the decay hierarchy
     // do it through the DecayChainTrack objects. These are looped over in sequence here
     // but they have the hierarchy information for the functions called to traverse the
     // decay chain.
 
     for( size_t index=0; index<decayChain.decayTracksSize; ++index )
     {
         ::DecayChainTrack* pDecayTrack=&decayChain.decayTracks[index];
         const SimTrack& simTrack=hSimTracks->at(pDecayTrack->simTrackIndex);
 
 
         // Perform some quick checks to see if we can drop out early. Note that these are
         // a subset of the cuts in the selector_ so the created TrackingParticle could still
         // fail. The selector_ requires the full TrackingParticle to be made however, which
         // can be computationally expensive.
         if( chargedOnly_ && simTrack.charge()==0 ) continue;
         if( signalOnly_ && (simTrack.eventId().bunchCrossing()!=0 || simTrack.eventId().event()!=0) ) continue;
 
         // Also perform a check to see if the production vertex is inside the tracker volume (if required).
         if( ignoreTracksOutsideVolume_ )
         {
             const SimVertex& simVertex=hSimVertices->at( pDecayTrack->pParentVertex->simVertexIndex );
             if( !objectFactory.vectorIsInsideVolume( simVertex.position() ) ) continue;
         }
 
 
         // This function creates the TrackinParticle and adds it to the collection if it
         // passes the selection criteria specified in the configuration. If the config
         // specifies adding ancestors, the function is called recursively to do that.
         ::addTrack( pDecayTrack, pSelector, pUnmergedCollectionWrapper.get(), pMergedCollectionWrapper.get(), objectFactory, addAncestors_ );
     }
 }

template<class T >

void TrackingTruthAccumulator::fillSimHits	(	std::vector< const PSimHit * > &	returnValue,
		const T &	event,
		const edm::EventSetup &	setup
	)

private

Fills the supplied vector with pointers to the SimHits, checking for bad modules if required.

Definition at line 454 of file TrackingTruthAccumulator.cc.

References collectionTags_.

Referenced by accumulateEvent().

 {
     // loop over the collections
     for( const auto& collectionTag : collectionTags_ )
     {
         edm::Handle< std::vector<PSimHit> > hSimHits;
         event.getByLabel( collectionTag, hSimHits );
 
         // TODO - implement removing the dead modules
         for( const auto& simHit : *hSimHits )
         {
             returnValue.push_back( &simHit );
         }
 
     } // end of loop over InputTags
 }

void TrackingTruthAccumulator::finalizeEvent	(	edm::Event &	event,
		const edm::EventSetup &	setup
	)

privatevirtual

Implements DigiAccumulatorMixMod.

Definition at line 345 of file TrackingTruthAccumulator.cc.

References createMergedCollection_, createUnmergedCollection_, mergedOutput_, TrackingTruthAccumulator::OutputCollections::pTrackingParticles, TrackingTruthAccumulator::OutputCollections::pTrackingVertices, and unmergedOutput_.

 {
 
     if( createUnmergedCollection_ )
     {
         edm::LogInfo("TrackingTruthAccumulator") << "Adding " << unmergedOutput_.pTrackingParticles->size() << " TrackingParticles and " << unmergedOutput_.pTrackingVertices->size()
                 << " TrackingVertexs to the event.";
 
         event.put( unmergedOutput_.pTrackingParticles );
         event.put( unmergedOutput_.pTrackingVertices );
     }
 
     if( createMergedCollection_ )
     {
         edm::LogInfo("TrackingTruthAccumulator") << "Adding " << mergedOutput_.pTrackingParticles->size() << " merged TrackingParticles and " << mergedOutput_.pTrackingVertices->size()
                 << " merged TrackingVertexs to the event.";
 
         event.put( mergedOutput_.pTrackingParticles, "MergedTrackTruth" );
         event.put( mergedOutput_.pTrackingVertices, "MergedTrackTruth" );
     }
 
 }

void TrackingTruthAccumulator::initializeEvent	(	const edm::Event &	event,
		const edm::EventSetup &	setup
	)

privatevirtual

Implements DigiAccumulatorMixMod.

Definition at line 309 of file TrackingTruthAccumulator.cc.

References createMergedCollection_, createUnmergedCollection_, event(), mergedOutput_, TrackingTruthAccumulator::OutputCollections::pTrackingParticles, TrackingTruthAccumulator::OutputCollections::pTrackingVertices, TrackingTruthAccumulator::OutputCollections::refTrackingParticles, TrackingTruthAccumulator::OutputCollections::refTrackingVertexes, and unmergedOutput_.

 {
     if( createUnmergedCollection_ )
     {
         unmergedOutput_.pTrackingParticles.reset( new TrackingParticleCollection );
         unmergedOutput_.pTrackingVertices.reset( new TrackingVertexCollection );
         unmergedOutput_.refTrackingParticles=const_cast<edm::Event&>( event ).getRefBeforePut<TrackingParticleCollection>();
         unmergedOutput_.refTrackingVertexes=const_cast<edm::Event&>( event ).getRefBeforePut<TrackingVertexCollection>();
     }
 
     if( createMergedCollection_ )
     {
         mergedOutput_.pTrackingParticles.reset( new TrackingParticleCollection );
         mergedOutput_.pTrackingVertices.reset( new TrackingVertexCollection );
         mergedOutput_.refTrackingParticles=const_cast<edm::Event&>( event ).getRefBeforePut<TrackingParticleCollection>("MergedTrackTruth");
         mergedOutput_.refTrackingVertexes=const_cast<edm::Event&>( event ).getRefBeforePut<TrackingVertexCollection>("MergedTrackTruth");
     }
 }

Member Data Documentation

const bool TrackingTruthAccumulator::addAncestors_

private

Whether or not to add the full parentage of any TrackingParticle that is inserted in the collection.

Definition at line 100 of file TrackingTruthAccumulator.h.

Referenced by accumulateEvent().

bool TrackingTruthAccumulator::allowDifferentProcessTypeForDifferentDetectors_

private

When counting hits, allows hits in different detectors to have a different process type.

Fast sim PSimHits seem to have a peculiarity where the process type (as reported by PSimHit::processType()) is different for the tracker than the muons. When counting how many hits there are, the code usually only counts the number of hits that have the same process type as the first hit. Setting this to true will also count hits that have the same process type as the first hit in the second detector.

Definition at line 123 of file TrackingTruthAccumulator.h.

Referenced by accumulateEvent().

bool TrackingTruthAccumulator::chargedOnly_

private

Uses the same config as selector_, but can be used to drop out early since selector_ requires the TrackingParticle to be created first.

Definition at line 112 of file TrackingTruthAccumulator.h.

Referenced by accumulateEvent(), and TrackingTruthAccumulator().

std::vector<edm::InputTag> TrackingTruthAccumulator::collectionTags_

private

Definition at line 106 of file TrackingTruthAccumulator.h.

Referenced by fillSimHits(), and TrackingTruthAccumulator().

const bool TrackingTruthAccumulator::createMergedCollection_

private

Definition at line 98 of file TrackingTruthAccumulator.h.

Referenced by accumulateEvent(), finalizeEvent(), initializeEvent(), and TrackingTruthAccumulator().

const bool TrackingTruthAccumulator::createUnmergedCollection_

private

If bremsstrahlung merging, whether to also add the unmerged collection to the event or not.

Definition at line 97 of file TrackingTruthAccumulator.h.

Referenced by accumulateEvent(), finalizeEvent(), initializeEvent(), and TrackingTruthAccumulator().

edm::InputTag TrackingTruthAccumulator::genParticleLabel_

private

Definition at line 107 of file TrackingTruthAccumulator.h.

Referenced by accumulateEvent(), and TrackingTruthAccumulator().

const bool TrackingTruthAccumulator::ignoreTracksOutsideVolume_

private

Definition at line 88 of file TrackingTruthAccumulator.h.

Referenced by accumulateEvent().

const unsigned int TrackingTruthAccumulator::maximumPreviousBunchCrossing_

private

The maximum bunch crossing BEFORE the signal crossing to create TrackinParticles for. Use positive values. If set to zero no previous bunches are added and only in-time, signal and after bunches (defined by maximumSubsequentBunchCrossing_) are used.

Definition at line 92 of file TrackingTruthAccumulator.h.

Referenced by accumulate().

const unsigned int TrackingTruthAccumulator::maximumSubsequentBunchCrossing_

private

The maximum bunch crossing AFTER the signal crossing to create TrackinParticles for. E.g. if set to zero only uses the signal and in time pileup (and previous bunches defined by the maximumPreviousBunchCrossing_ parameter).

Definition at line 95 of file TrackingTruthAccumulator.h.

Referenced by accumulate().

OutputCollections TrackingTruthAccumulator::mergedOutput_

private

Definition at line 136 of file TrackingTruthAccumulator.h.

Referenced by accumulateEvent(), finalizeEvent(), and initializeEvent().

const std::string TrackingTruthAccumulator::messageCategory_

private

The message category used to send messages to MessageLogger.

Definition at line 84 of file TrackingTruthAccumulator.h.

Referenced by accumulate(), and TrackingTruthAccumulator().

const bool TrackingTruthAccumulator::removeDeadModules_