MatchFromCompositeTool.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
#include "TriggerMatchingTool/MatchFromCompositeTool.h"
#include "FourMomUtils/xAODP4Helpers.h"
 
#include "CxxUtils/crc64.h"
#include <format>
#include <stdexcept>
 
#ifdef XAOD_STANDALONE
namespace {
    SG::sgkey_t hashContainer(const std::string &container, CLID clid)
    {
        static const SG::sgkey_t sgkey_t_max = (static_cast<SG::sgkey_t>(1) << 30) - 1;
        return CxxUtils::crc64addint(CxxUtils::crc64(container), clid) & sgkey_t_max;
    }
}
#endif
 
namespace Trig {
  MatchFromCompositeTool::MatchFromCompositeTool(const std::string& name) :
    asg::AsgTool(name)
  {
    declareProperty("MatchShallow", m_matchShallow,
        "Whether to check if two objects are shallow copies of each other. "
        "If this is not true then pointer equality will be used.");
    declareProperty("DRThreshold", m_drThreshold,
        "If greater than 0 then use the DR between two objects to check if "
        "they are the same object.");
    declareProperty("InputPrefix", m_inputPrefix="TrigMatch_",
        "The input prefix to expect at the beginning of the TrigComposite "
        "container names.");
#ifdef XAOD_STANDALONE
    declareProperty("RemapBrokenLinks", m_remapBrokenLinks,
        "Whether to remap element links which are broken in some derivations for AnalysisBase");
    declareProperty("RemapContainers", m_remapContainers,
        "Containers whose links need remapping");
    declareProperty("RemapCLIDs", m_remapCLIDs, "CLIDs for those containers");
#endif
  }
 
  MatchFromCompositeTool::~MatchFromCompositeTool() {}
 
  StatusCode MatchFromCompositeTool::initialize() {
    ATH_MSG_INFO( "initializing " << name() );
#ifdef XAOD_STANDALONE
    ATH_MSG_INFO("Remap broken links? " << m_remapBrokenLinks);
    if (m_remapBrokenLinks)
    {
        if (m_remapContainers.size() != m_remapCLIDs.size())
        {
            ATH_MSG_ERROR("Number of containers and CLIDs to remap do not match!");
            return StatusCode::FAILURE;
        }
        CLID iparticleCLID = ClassID_traits<xAOD::IParticleContainer>::ID();
        for (std::size_t idx = 0; idx < m_remapContainers.size(); ++idx)
        {
            const std::string &name = m_remapContainers[idx];
            m_keyRemap[hashContainer(name, iparticleCLID)] = hashContainer(name, m_remapCLIDs[idx]);
        }
        ATH_MSG_INFO("Remap: ");
        for (const auto &p : m_keyRemap)
            ATH_MSG_INFO("\t" << p.first << " -> " << p.second);
 
    }
#endif
    return StatusCode::SUCCESS;
  }
 
  bool MatchFromCompositeTool::match  (
      const xAOD::IParticle& recoObject,
      std::string_view chain,
      double, bool) const
  {
    return match({&recoObject}, chain);
  }
 
  bool MatchFromCompositeTool::match(
      const std::vector<const xAOD::IParticle*>& recoObjects,
      std::string_view chain,
      double, bool) const
  {
    std::string containerName = m_inputPrefix;
    containerName.append(chain);
    // We have to replace '.' characters with '_' characters so that these are
    // valid container names...
    std::replace(containerName.begin(), containerName.end(), '.', '_');
    const xAOD::TrigCompositeContainer* composites(nullptr);
    if (evtStore()->retrieve(composites, containerName).isFailure() ){
      ATH_MSG_ERROR("Failed to retrieve composite container for chain "<< chain);
      ATH_MSG_ERROR("Please check your derivation to see if the container is there");
      ATH_MSG_ERROR("This likely means the trigger is not in your file's menu");
      throw std::runtime_error(
          std::format("Failed to retrieve composite corresponding to chain {}",chain));
    }
    const constAcc_t<vecLink_t<xAOD::IParticleContainer>> accMatched("TrigMatchedObjects");
    for (const xAOD::TrigComposite* composite : *composites) {
      if (testCombination(accMatched(*composite), recoObjects) )
        return true;
    }
    // If we get here then none of the online combinations worked
    return false;
  }
 
  bool MatchFromCompositeTool::testCombination(
      const vecLink_t<xAOD::IParticleContainer>& onlineLinks,
      const std::vector<const xAOD::IParticle*>& offline) const
  {
    // We need to make sure we don't allow two offline particles to match to the
    // same online particle, so we copy the vector so we can erase objects if
    // necessary. Dereference the links at the same time.
    std::vector<const xAOD::IParticle*> online;
    online.reserve(onlineLinks.size() );
    for (const ElementLink<xAOD::IParticleContainer>& link : onlineLinks)
      // Skip invalid links - these are usually objects that have been removed
      // by derivation framework level thinning. Going by the logic that we just
      // need a match for all the offline particles provided rather than for the
      // trigger particles implies that we should allow a combination that has
      // had some of its members removed.
      if (link.isValid() )
        online.push_back(*link);
#ifdef XAOD_STANDALONE
      else if (m_remapBrokenLinks)
      {
        auto itr = m_keyRemap.find(link.persKey());
        if (itr != m_keyRemap.end())
            online.push_back(*ElementLink<xAOD::IParticleContainer>(itr->second, link.index()));
      }
#endif
    // I will follow the way the current tool works and match even if there are
    // fewer reco objects than trigger objects
    for (const xAOD::IParticle* offlinePart : offline) {
      bool isMatched = false;
      for (auto itr = online.begin(); itr != online.end(); ++itr) {
        if (areTheSame(*offlinePart, **itr) ) {
          // Remove this online particle from consideration
          online.erase(itr);
          isMatched = true;
          break;
        }
      }
      if (!isMatched)
        // We've found an offline particle we couldn't match so the whole
        // combination doesn't match.
        return false;
    }
    // To reach this point every offline particle must have found a match.
    return true;
  }
 
  bool MatchFromCompositeTool::areTheSame(
      const xAOD::IParticle& lhs,
      const xAOD::IParticle& rhs) const
  {
    // If we've been given a dR threshold > 0 then we just use that.
    if (m_drThreshold > 0) {
      return xAOD::P4Helpers::deltaR(lhs, rhs, false) < m_drThreshold;
    }
    else if (m_matchShallow) {
      static const SG::AuxElement::ConstAccessor<
        ElementLink<xAOD::IParticleContainer>> accOOL("originalObjectLink");
      // For now assume that we've got a shallow copy iff this is available
      const xAOD::IParticle* lhsOrig = 
        accOOL.isAvailable(lhs) ? *accOOL(lhs) : &lhs;
      const xAOD::IParticle* rhsOrig = 
        accOOL.isAvailable(rhs) ? *accOOL(rhs) : &rhs;
      return lhsOrig == rhsOrig;
    }
    else {
      // Otherwise just use pointer equality
      return &lhs == &rhs;
    }
  }
 
} //> end namespace Trig