ChainGroup.cxx

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/*
  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
*/
 
/**********************************************************************************
 * @Project: TrigDecisionTool
 * @Package: TrigDecisionTool
 * @Class  : ChainGroup
 *
 * @brief simple container to hold trigger chains
 *
 * @author Michael Begel  <michael.begel@cern.ch> - Brookhaven National Laboratory
 * @author Alexander Mann  <mann@cern.ch> - University of Goettingen
 *
 ***********************************************************************************/
#include <limits>
#include "boost/regex.hpp"
#include "boost/range/adaptor/reversed.hpp"
 
#include "CxxUtils/bitmask.h"
#include "TrigConfHLTData/HLTChain.h"
#include "TrigConfHLTData/HLTStreamTag.h"
#include "TrigConfHLTData/HLTSignature.h"
#include "TrigConfHLTData/HLTTriggerElement.h"
#include "TrigConfHLTUtils/HLTUtils.h"
#include "TrigConfL1Data/TriggerItem.h"
#include "TrigConfL1Data/TriggerItemNode.h"
#include "TrigSteeringEvent/Chain.h"
#include "TrigSteeringEvent/Lvl1Item.h"
#include "TrigNavStructure/ComboIterator.h"
#include "xAODTrigger/TrigCompositeContainer.h"
 
#include "TrigDecisionTool/ChainGroup.h"
#include "TrigDecisionTool/TDTUtilities.h"
#include "TrigDecisionTool/Logger.h"
 
 
 
using namespace std;
 
Trig::ChainGroup::ChainGroup(const std::vector< std::string >& triggerNames,
                             Trig::CacheGlobalMemory& parent)
  :
  m_patterns(triggerNames),
  m_cgm(parent)
{}
 
const Trig::ChainGroup& Trig::ChainGroup::operator+(const Trig::ChainGroup& rhs) {
  std::vector< std::string > v;
  v.resize(patterns().size()+rhs.patterns().size());
  merge(patterns().begin(), patterns().end(),
        rhs.patterns().begin(), rhs.patterns().end(),
        v.begin());
  return *(cgm().createChainGroup(v));
}
 
 
bool Trig::ChainGroup::operator==(const Trig::ChainGroup& rhs) {
  return Trig::keyWrap(names())==Trig::keyWrap(rhs.names());
}
 
bool Trig::ChainGroup::operator!=(const Trig::ChainGroup& rhs) {
  return !(*this==rhs);
}
 
void Trig::ChainGroup::addAlias(const std::string& alias) {
  cgm().createChainGroup(patterns(),alias);
}
 
const Trig::CacheGlobalMemory& Trig::ChainGroup::cgm_assert() const {
  // thread-safe because assert_decision is locked
  auto nonconst_cgm ATLAS_THREAD_SAFE = const_cast<Trig::CacheGlobalMemory*>(&cgm());
  nonconst_cgm->assert_decision();
 
  return cgm();
}
 
bool Trig::ChainGroup::HLTResult(const std::string& chain, unsigned int condition) const {
  bool chainRESULT = false;
  if (chain.empty()) return chainRESULT;
  const HLT::Chain* fchain=cgm_assert().chain(chain);
  if (fchain==nullptr) return chainRESULT;
  
  
  bool RAW               = fchain->chainPassedRaw();
  const bool PASSTHROUGH = fchain->isPassedThrough();
  const bool PRESCALED   = fchain->isPrescaled();
  const bool RESURRECTED = fchain->isResurrected();
  
  // Resurrection overwrites the value in RAW but sets the RESURRECTED flag
  // we should therefore fix RAW appropriately
  if (~condition & TrigDefs::allowResurrectedDecision) {
    if (RESURRECTED) {
      RAW=false;
    }
  }
  //
  // Do we accept the result?
  //
  if (condition & TrigDefs::passedThrough) {
    if (PASSTHROUGH) {chainRESULT=true;}
  }
  if (condition & TrigDefs::requireDecision) {
    if (RAW && !PRESCALED) {chainRESULT=true;}
    if ( condition & TrigDefs::allowResurrectedDecision ) { // prescaling does not matter for RR (it runs in fact because of that
      if (RAW) {chainRESULT=true;}      
    }
 
  }
  // respects resurrection -- is this the appropriate behavior???
  if (condition & TrigDefs::eventAccepted) {
    if ( (RAW  && !PRESCALED) ||  PASSTHROUGH) {chainRESULT=true;}
  }
  ATH_MSG_DEBUG("ChainGroup::HLTResult Counter = " << std::setw(4) << fchain->getChainCounter()
        << " name = "  << fchain->getChainName()
        << " level = " << fchain->getConfigChain()->level()
        << " success (raw) = " << fchain->chainPassedRaw()
        << " pass-through = " << fchain->isPassedThrough()
        << " prescaled = " << fchain->isPrescaled()
        << " rerun = " << fchain->isResurrected()
        << " lastActiveStep = " << fchain->getChainStep()
        << " name = " << std::setw(35) << fchain->getChainName() 
        << " result = " << chainRESULT);
 
  return chainRESULT;
}
 
// this logic fails for passthrough especially with enforceLogicalFlow!!!!
bool Trig::ChainGroup::L1Result(const std::string& item, unsigned int condition) const {
  bool r = false;
  if (item.empty()) return r;
  if (item.find(',')!=std::string::npos) {
    for(const std::string& item : convertStringToVector(item)) {
      if(L1Result(item,condition)) return true;
    }
    return false;
  }
  const LVL1CTP::Lvl1Item* fitem=cgm_assert().item(item);
  if (fitem==nullptr) {
    return r;
  }
  ATH_MSG_DEBUG(" success (raw) = " << fitem->isPassedBeforePrescale()
        << " prescaled = " << fitem->isPrescaled()
        << " vetoed = " << fitem->isVeto()
        << " name = " << std::setw(35) << fitem->name()); 
 
  r = fitem->isPassedAfterVeto();
 
  if (condition & TrigDefs::allowResurrectedDecision)
    r = fitem->isPassedBeforePrescale();
 
  //if (condition & TrigDefs::eventAccepted) 
  //  r = fitem->isPassedAfterVeto();
  //else
  //  r = fitem->isPassedBeforePrescale();
  return r;
}
 
 
std::string Trig::ChainGroup::getLowerName(const std::string& name) const {
  if ( name.empty() )
    return name;
  const TrigConf::HLTChain* cchain = cgm().config_chain(name);
  if (cchain==nullptr){
    ATH_MSG_WARNING(" Lower chain name used by:  " << name << " is not in the configuration ");
    return "BAD NAME";
  }
  return cchain->lower_chain_name();
}
 
// Helper to get decision of a single chain (private)
bool Trig::ChainGroup::isPassed(const TrigConf::HLTChain& chain, unsigned int condition) const
{
  bool result = HLTResult(chain.chain_name(),condition);
  if (result && (condition & TrigDefs::enforceLogicalFlow)) {
    // enforceLogicalFlow
    if (chain.level()=="EF") {
      const std::string& nexttwo = getLowerName(chain.chain_name());
      result = result && HLTResult(nexttwo,condition);
      result = result && L1Result(getLowerName(nexttwo),condition);
 
    } else if (chain.level()=="L2") {
      result = result && L1Result(getLowerName(chain.chain_name()),condition);
 
    } else if (chain.level()=="HLT"){
      result = result && L1Result(getLowerName(chain.chain_name()),condition);
    }
  }
 
  return result;
}
 
std::vector<bool> Trig::ChainGroup::isPassedForEach(unsigned int condition) const
{
  std::vector<bool> result;
  result.reserve(m_confChains.size() + m_confItems.size());
 
  for (const TrigConf::HLTChain* ch : m_confChains) {
    result.push_back( isPassed(*ch, condition) );
  }
  for (const TrigConf::TriggerItem* item : m_confItems) {
    result.push_back( L1Result(item->name(), condition) );
  }
 
  return result;
}
 
bool Trig::ChainGroup::isPassed(unsigned int condition) const
{
  if (condition & TrigDefs::Express_passed) {
    ATH_MSG_ERROR("Incorrect use of Express_passed bit. Please use isPassedBits() and test for TrigDefs::Express_passed in the returned bit-map.");
  }
 
  // True if any HLT or L1 item passed
  return ( std::any_of(m_confChains.cbegin(), m_confChains.cend(),
                       [&](const TrigConf::HLTChain* ch) {return isPassed(*ch, condition);}) ||
           std::any_of(m_confItems.cbegin(), m_confItems.cend(),
                       [&](const TrigConf::TriggerItem* item) {return L1Result(item->name(), condition);}) );
}
 
unsigned int Trig::ChainGroup::HLTBits(const std::string& chain, const std::string& level, const TrigCompositeUtils::DecisionIDContainer& passExpress) const {
  unsigned int chainRESULT = 0;
  if (chain.empty()) return chainRESULT;
  const HLT::Chain* fchain = cgm_assert().chain(chain);
  if (fchain==nullptr) return chainRESULT;
  if (level=="L2") {
    if (fchain->chainPassedRaw())  chainRESULT = chainRESULT | TrigDefs::L2_passedRaw;
    if (fchain->isPassedThrough()) chainRESULT = chainRESULT | TrigDefs::L2_passThrough;
    if (fchain->isPrescaled())     chainRESULT = chainRESULT | TrigDefs::L2_prescaled;
    if (fchain->isResurrected())   chainRESULT = chainRESULT | TrigDefs::L2_resurrected;
  } else {//L2EF merged use same EF bits
    if (fchain->chainPassedRaw())  chainRESULT = chainRESULT | TrigDefs::EF_passedRaw;
    if (fchain->isPassedThrough()) chainRESULT = chainRESULT | TrigDefs::EF_passThrough;
    if (fchain->isPrescaled())     chainRESULT = chainRESULT | TrigDefs::EF_prescaled;
    if (fchain->isResurrected())   chainRESULT = chainRESULT | TrigDefs::EF_resurrected;
 
    if (passExpress.count( HLT::Identifier(chain).numeric() ) == 1) {
      chainRESULT = chainRESULT | TrigDefs::Express_passed; 
    }
  }
  return chainRESULT;
}
 
unsigned int Trig::ChainGroup::L1Bits(const std::string& item) const {
  unsigned int r = 0;
  if (item.empty()) return r;
  if (item.find(',')!=std::string::npos) {
    for(const std::string& item : convertStringToVector(item)) {
      r |= L1Bits(item);
    }
    return r;
  }
  const LVL1CTP::Lvl1Item* fitem = cgm_assert().item(item);
  if (fitem==nullptr) return r;
  if (fitem->isPassedBeforePrescale()) r = r | TrigDefs::L1_isPassedBeforePrescale;
  if (fitem->isPassedAfterPrescale())  r = r | TrigDefs::L1_isPassedAfterPrescale;
  if (fitem->isPassedAfterVeto())      r = r | TrigDefs::L1_isPassedAfterVeto;
  return r;
}
 
std::vector<unsigned int> Trig::ChainGroup::isPassedBitsForEach() const
{
  // This is for the express decision (R3 only), we read this directly from the navigation (not from bits)
  const SG::ReadHandleKey<TrigCompositeUtils::DecisionContainer>* navRHK = cgm().getRun3NavigationKeyPtr();
  TrigCompositeUtils::DecisionIDContainer passExpress;
  if (navRHK && !navRHK->empty()) {
    SG::ReadHandle<TrigCompositeUtils::DecisionContainer> navRH(*navRHK); // No good way to pass in the context here?
    if (navRH.isValid()) {
      const TrigCompositeUtils::Decision* expressTerminusNode = TrigCompositeUtils::getExpressTerminusNode(*navRH);
      if (expressTerminusNode) {
        TrigCompositeUtils::decisionIDs(expressTerminusNode, passExpress);
      }
    }
  }
 
  std::vector<unsigned int> all;
  all.reserve(m_confChains.size() + m_confItems.size());
 
  for ( const TrigConf::HLTChain* ch : m_confChains ) {
 
    unsigned int RESULT = HLTBits(ch->chain_name(), ch->level(), passExpress);
 
    if (ch->level()=="EF") {
      const std::string& nexttwo = getLowerName(ch->chain_name());
      RESULT = RESULT | HLTBits(nexttwo,"L2", passExpress);
      RESULT = RESULT | L1Bits(getLowerName(nexttwo));
      
    } else if (ch->level()=="L2") {
      RESULT = RESULT | L1Bits(getLowerName(ch->chain_name()));
      
    } else if (ch->level()=="HLT") {
      RESULT = RESULT | L1Bits(getLowerName(ch->chain_name()));
    }
 
    all.push_back(RESULT);
  }
 
  for ( const TrigConf::TriggerItem* item : m_confItems ) {
    all.push_back( L1Bits(item->name()) );
  }
 
  return all;
}
 
unsigned int Trig::ChainGroup::isPassedBits() const
{
  const std::vector<unsigned int> all = isPassedBitsForEach();
  unsigned int result = 0;
  for (unsigned int r : all) {
    result = result | r;
  }
  return result;
}
 
HLT::ErrorCode Trig::ChainGroup::error() const {
  HLT::ErrorCode errorCode = HLT::OK;  
  for ( const TrigConf::HLTChain* ch : m_confChains ) {
    const HLT::Chain* fchain = cgm_assert().chain(ch->chain_name());
    if (fchain==nullptr) continue;
    HLT::ErrorCode ec = fchain->getErrorCode();
    errorCode = errorCode > ec ? errorCode : ec;
  }
  return errorCode;
}
 
float Trig::ChainGroup::HLTPrescale(const std::string& chain, unsigned int /*condition*/) const {
  if (chain=="") return 0.;
 
  const TrigConf::HLTChain* fchain=cgm().config_chain(chain);
  if (fchain==0) { // this is error condition, we always need configuration of the chains in the chaon group!
    ATH_MSG_WARNING("Configuration for the chain: " << chain << " not known");
    return std::numeric_limits<float>::quiet_NaN();
  }
  float chainRESULT = fchain->prescale();
  
  if (chainRESULT < 1)
    chainRESULT = 0.;
    
  return chainRESULT;
}
 
 
bool Trig::ChainGroup::isCorrelatedL1items(const std::string& item) const {
  if( (item == "L1_MU20,L1_MU21") || (item == "L1_MU21,L1_MU20") ) return true;
  return false;
}
 
float Trig::ChainGroup::correlatedL1Prescale(const std::string& item) const {
  if( (item == "L1_MU20,L1_MU21") || (item == "L1_MU21,L1_MU20") ) {
    //see discussion in ATR-16612
    auto l1mu20 = cgm().config_item("L1_MU20");
    if (l1mu20==nullptr) {
      ATH_MSG_WARNING("Configuration for the item L1_MU20 not known");
      return std::numeric_limits<float>::quiet_NaN();
    }
    float l1mu20ps = cgm().item_prescale(l1mu20->ctpId());
 
    auto l1mu21 = cgm().config_item("L1_MU21");
    if (l1mu21==nullptr) {
      ATH_MSG_WARNING("Configuration for the item L1_MU21 not known");
      return std::numeric_limits<float>::quiet_NaN();
    }
    float l1mu21ps = cgm().item_prescale(l1mu21->ctpId());
    
    if( (l1mu20ps  < 1.0) && (l1mu21ps < 1.0) ) return 0.0;
    if( (l1mu20ps  < 1.0) ) return l1mu21ps;
    if( (l1mu21ps  < 1.0) ) return l1mu20ps;
    if(l1mu20ps == 1.0) return 1.0;
    return 0.0;
  }
  return 0.0;
}
 
float Trig::ChainGroup::L1Prescale(const std::string& item, unsigned int /*condition*/) const {
  if (item.empty()) return 0;
 
  if(item.find(',')==std::string::npos) {
    const TrigConf::TriggerItem* fitem=cgm().config_item(item);
    if (fitem==nullptr) {
      ATH_MSG_WARNING("Configuration for the item: " << item << " not known");
      return std::numeric_limits<float>::quiet_NaN();
    }
    // now we can;t access the prescale value because this information doe not come togehther as in HLT
    // we need to go to the cache of L1 items and get it from there  
    float itemprescale = cgm().item_prescale(fitem->ctpId());
    if ( itemprescale < 1) itemprescale = 0;
    return itemprescale;
  } else if(isCorrelatedL1items(item)) {
    return correlatedL1Prescale(item);
  } else {
    float minprescale=0;
    for(const std::string& item : convertStringToVector(item)) {
 
      const TrigConf::TriggerItem* fitem=cgm().config_item(item);
      if (fitem==nullptr) {
        ATH_MSG_WARNING("Configuration for the item: " << item << " not known");
        return std::numeric_limits<float>::quiet_NaN();
      }
      float itemprescale = cgm().item_prescale(fitem->ctpId());
      if ( itemprescale < 1) itemprescale = 0;
      minprescale = (minprescale&&(minprescale<itemprescale)?minprescale:itemprescale); // takes min, except the first time
    }
    return minprescale;
  }
}
 
float Trig::ChainGroup::getPrescale(unsigned int condition) const {
  if ( condition != TrigDefs::Physics )
    return 0.0;
  return m_prescale;
}
 
float Trig::ChainGroup::calculatePrescale(unsigned int condition)
{
  bool singleTrigger = (m_confChains.size()+m_confItems.size()==1);
  
  for ( const TrigConf::HLTChain* ch : m_confChains ) {
    
    const std::string& hltChainName = ch->chain_name();
    float chainRESULT = HLTPrescale(hltChainName,condition);
    
    if (condition & TrigDefs::enforceLogicalFlow) {
      // enforceLogicalFlow
      if (ch->level()=="EF") {
        const std::string& hltChainNameL2 = getLowerName(hltChainName);
        const std::string& l1ItemName     = getLowerName(hltChainNameL2);
        chainRESULT *= HLTPrescale(hltChainNameL2,condition);
        chainRESULT *= L1Prescale(l1ItemName,condition);
        if(l1ItemName.find(',')!=std::string::npos) singleTrigger=false;
    
      } else if (ch->level()=="L2") {
        const std::string& l1ItemName       = getLowerName(hltChainName);
        chainRESULT *= L1Prescale(l1ItemName,condition);
        if(l1ItemName.find(',')!=std::string::npos) singleTrigger=false;
 
      } else if (ch->level()=="HLT") {
        const std::string& l1ItemName       = getLowerName(hltChainName);
        chainRESULT *= L1Prescale(l1ItemName,condition);
        if(l1ItemName.find(',')!=std::string::npos and !isCorrelatedL1items(l1ItemName) ) singleTrigger=false;
      }
    }
 
    if (singleTrigger) return chainRESULT;  // for a single trigger we are done
 
    const bool UNPRESCALED = (fabs(chainRESULT-1.0)<1e-5);
 
    if (UNPRESCALED) return 1.0; // any unprescaled trigger and we are done too
  }
 
 
  for ( const TrigConf::TriggerItem* item : m_confItems ) {
    const std::string& l1ItemName = item->name();
    const float itemRESULT = L1Prescale(l1ItemName, condition);
    if(l1ItemName.find(',')!=std::string::npos) singleTrigger=false;
 
    if (singleTrigger) return itemRESULT; // for a single trigger we are done
 
    const bool UNPRESCALED = (itemRESULT==1);
 
    if (UNPRESCALED) return 1.0; // any unprescaled trigger and we are done too
  }
 
  return 0.0; // multiple triggers and all are prescaled
}
 
 
std::vector< std::string > Trig::ChainGroup::getListOfTriggers() const {
  return m_names;
}
 
 
std::vector< std::string > Trig::ChainGroup::getListOfStreams() const {
  std::set< std::string > streams;
  for ( const TrigConf::HLTChain* ch : m_confChains ) {
    for ( const TrigConf::HLTStreamTag* s : ch->streams() ) {
      streams.insert(s->stream());
    }
  }
  return {streams.begin(), streams.end()};
}
 
//
// Groups
//
 
vector<string>
Trig::ChainGroup::getListOfGroups() const {
 
   vector< string > v;
 
   for( const TrigConf::HLTChain* ch : m_confChains )
      v.assign( ch->groups().begin(), ch->groups().end() );
 
   return v;
}
 
//
// Signatures
//
 
std::vector< std::string > Trig::ChainGroup::getListOfSignatures() const {
  std::set< std::string > sig;
  for ( const TrigConf::HLTChain* ch : m_confChains ) {
    for ( const TrigConf::HLTSignature* s : ch->signatureList() ) {
      sig.insert(s->label());
    }
  }
  return {sig.begin(), sig.end()};
}
 
 
//
// Return level 1 thresholds
//
 
vector<string>
Trig::ChainGroup::getListOfThresholds() const {
 
   set<string> s;   // using a set makes the items in the result vector unique
   std::stack<const TrigConf::TriggerItemNode*> nodes;
   const TrigConf::TriggerItemNode* node;
 
   for( const TrigConf::TriggerItem* item : m_confItems ) {
      nodes.push( item->topNode() );
      while (!nodes.empty()) {
         node = nodes.top(); nodes.pop();
         if (node == NULL)
            continue;
         if (node->isThreshold()) {
            if (node->triggerThreshold()) {
               // available if thresholds have been read in
               if (!node->triggerThreshold()->name().empty())
                  s.insert(node->triggerThreshold()->name());
            } else if (!node->thresholdName().empty()) {
               // fall back solution
               s.insert(node->thresholdName());
            }
         } else {
           for(TrigConf::TriggerItemNode* childnode : node->children()) {
               nodes.push(childnode);
            }
         }
      }
      // I am not using (*it)->topNode()->getAllThresholds() here, because it returns nothing when only ItemDef (and not the thresholds themselves) are defined
   }
 
   return {s.begin(), s.end()};
}
 
 
//
// Trigger Elements
//
 
std::vector< std::vector< std::string > > Trig::ChainGroup::getListOfTriggerElements() const {
 
  std::set< std::vector< std::string > > tes;
  std::vector< std::string > t;
 
  for( const TrigConf::HLTChain* ch : m_confChains ) {
    for ( const TrigConf::HLTSignature* s : ch->signatureList() ) {
      t.clear();
      for ( const TrigConf::HLTTriggerElement* te : s->outputTEs() ) {
        t.push_back( te->name());
      }
      tes.insert(t);
    }
  }
  return {tes.begin(), tes.end()};
}
 
 
//
// get vector of vector with all Trigger Elements
//
 
std::vector< std::vector< TrigConf::HLTTriggerElement* > > Trig::ChainGroup::getHLTTriggerElements() const {
 
  std::set< std::vector< TrigConf::HLTTriggerElement* > > tes;
 
  for( const TrigConf::HLTChain* ch : m_confChains ) {
    for ( const TrigConf::HLTSignature* s : ch->signatureList() ) {
      tes.insert(s->outputTEs());
    }
  }
  return {tes.begin(), tes.end()};
}
 
 
void
Trig::ChainGroup::update(const TrigConf::HLTChainList* confChains,
                         const TrigConf::ItemContainer* confItems,
                         TrigDefs::Group prop) {
 
   m_confChains.clear();
   m_confItems.clear();
   m_names.clear();
 
   // protect against genConf failure
   if (!(confChains && confItems) ) return;
 
   if (!CxxUtils::test(prop, TrigDefs::Group::NoRegex)) {
 
     for(const std::string& pat : m_patterns) {
        // find chains matching pattern
        boost::regex compiled(pat);
        boost::cmatch what;
 
        for(TrigConf::HLTChain* ch : *confChains) {
           if ( boost::regex_match(ch->chain_name().c_str(), what, compiled) ) {
              m_confChains.push_back(ch);
           }
        }
 
        for(TrigConf::TriggerItem* item : *confItems) {
           if ( boost::regex_match( item->name().c_str(), what, compiled) ) {
              m_confItems.push_back(item);
           }
        }
     }
   
   } else { // Do not parse as regex
 
     for(const std::string& what : m_patterns) {
 
        bool found_it = false;
 
        for(TrigConf::HLTChain* ch : *confChains) {
           if (ch->chain_name() == what) {
              m_confChains.push_back(ch);
              found_it = true;
              break;
           }
        }
 
        if (found_it) {
           continue;
        }
 
        for(TrigConf::TriggerItem* item : *confItems) {
           if (item->name() == what) {
              m_confItems.push_back(item);
              found_it = true;
              break;
           }
        }
 
        if (found_it) {
           continue;
        }
 
        ATH_MSG_WARNING("Explicitly requested '" << what << "' be added to a ChainGroup"
          << " but this item or chain could not be found in the menu");
     }
 
   } // parseAsRegex
 
   // Cache the names of all triggers
   m_names.reserve(m_confChains.size() + m_confItems.size());
   for (const TrigConf::HLTChain* ch : m_confChains)     m_names.push_back(ch->chain_name());
   for (const TrigConf::TriggerItem* item : m_confItems) m_names.push_back(item->name());
 
   m_prescale = calculatePrescale(TrigDefs::Physics);
}
 
// features
 
namespace ChainGroup_impl {
   using namespace HLT;
   using namespace Trig;
 
   bool allActive(const std::vector<TriggerElement*>& tes) {
     for(TriggerElement* te : tes){
         if (te->getActiveState() == false)
            return false;
      }
      return true;
   }
 
 
  
   void collectCombinations( const TrigConf::HLTChain* conf, const CacheGlobalMemory& cgm, FeatureContainer& fc, unsigned int condition ){
      // go over the steps of the chain and collecte TEs combinations for each of the chain step (signature)
      bool last_step=true;
      const TrigConf::HLTSignature* previous_sig(0);
      for(const TrigConf::HLTSignature* sig : boost::adaptors::reverse(conf->signatureList())) {
         // chain without signatures
         if (!sig) break;
 
         // the signatures size changes from step to step, this needs custom treatement and the iteration eeds to be stoped here
         if ( previous_sig && previous_sig->outputTEs().size() != sig->outputTEs().size() )
            break;
         previous_sig = sig;
 
         std::vector<std::vector<HLT::TriggerElement*> > tes(sig->outputTEs().size()); // preallocate     
         size_t idx = 0;
         for(const TrigConf::HLTTriggerElement* confte : sig->outputTEs() ) {
 
            // here the condition enters; if we take only accepted objects we need to pick only the active TEs
            cgm.navigation()->getAllOfType(confte->id(), tes[idx], condition & TrigDefs::Physics );
            idx++;
         }
         HLT::ComboIterator combination(tes, cgm.navigation());
 
         // build the combinations, sometimes a huge list
         while (combination.isValid()) {
            // very very tricky, if all TEs in the combination are active then it means they were already picked up by previous combinations
            // but we can not do this for the last chain step, (we woudl be unable to pick objects whcih made trigger passing)
            //std::cerr << "emitting new combination last_step: "<< last_step << std::endl; 
            if (!allActive(*combination) || last_step) {
               fc.addWithChecking(Combination(*combination, &cgm));
            }
            ++combination;
         }
 
         if ( condition & TrigDefs::Physics ) // here again athe condition calls for the loop breaking
            break;
         else
            last_step = false; // and go deeper
      }
   }
}// eof namespace
 
const Trig::FeatureContainer 
Trig::ChainGroup::features(unsigned int condition) const {
   using namespace ChainGroup_impl;
   FeatureContainer f(&cgm_assert());
 
   // this loop only applies to L2 and EF chain groups
   for (const TrigConf::HLTChain* ch : m_confChains) {
      const HLT::Chain* fchain = cgm_assert().chain(*ch);
      if (fchain) {
         collectCombinations(fchain->getConfigChain(), cgm_assert(), f, condition);
      }
   }
 
   // this part only applies to L1 chain groups
   std::vector< std::vector< HLT::TriggerElement*> > tes;
   std::vector< std::vector< HLT::TriggerElement*> >::iterator tesit;
 
   for(const TrigConf::TriggerItem* item : m_confItems) {
 
      std::set< std::string > threshold_names;
      std::stack<const TrigConf::TriggerItemNode*> nodes;
 
      nodes.push( item->topNode() );
 
      // collect unique list (= set) of threshold names for this item
      while (!nodes.empty()) {
         const TrigConf::TriggerItemNode* node = nodes.top();
         nodes.pop();
         if (node == nullptr)
            continue;
         if (node->isThreshold()) {
            if (node->triggerThreshold()) {
               // available if thresholds have been read in
               if (!node->triggerThreshold()->name().empty())
                  threshold_names.insert(node->triggerThreshold()->name());
            } else if (!node->thresholdName().empty()) {
               // fall back solution
               threshold_names.insert(node->thresholdName());
            }
         }
         for(TrigConf::TriggerItemNode* childnode : node->children()) {
            nodes.push(childnode);
         }
      }
 
      // collect corresponding TEs and add them using appendFeatures()
      tes.clear();
      tes.resize(threshold_names.size());   
      tesit = tes.begin();
      std::set< std::string >::iterator setstrit;
 
      for (setstrit = threshold_names.begin(); setstrit != threshold_names.end(); ++setstrit, ++tesit) {
         cgm_assert().navigation()->getAllOfType(TrigConf::HLTUtils::string2hash(*setstrit), *tesit, true);
      }
 
      appendFeatures(tes, f);    
   }
    
   ATH_MSG_DEBUG("features: features container size: "<< f.getCombinations().size());
   return f;
}
 
 
void Trig::ChainGroup::appendFeatures(std::vector< std::vector< HLT::TriggerElement*> >& tes, Trig::FeatureContainer& fc) const {
 
  // appends (combinations of) TriggerElements to FeatureContainer
  if (tes.empty()) // ComboIterator::isValid would return true in this case
    return;
 
  HLT::ComboIterator combination(tes, cgm_assert().navigation());
  while (combination.isValid()) {
    fc.addWithChecking(Combination(*combination, &cgm_assert()));
 
    ATH_MSG_VERBOSE(" adding combination" << Combination(*combination, &cgm_assert()));
 
    ++combination;
  }
}