ParticleMCDecayStringModule.cc

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#include <analysis/modules/ParticleMCDecayString/ParticleMCDecayStringModule.h>
 
#include <mdst/dataobjects/MCParticle.h>
 
#include <framework/logging/Logger.h>
#include <framework/pcore/ProcHandler.h>
 
#include <string>
#include <vector>
 
#include <boost/algorithm/string.hpp>
 
namespace Belle2 {
  REG_MODULE(ParticleMCDecayString)
 
  ParticleMCDecayStringModule::ParticleMCDecayStringModule() : Module(), m_tree("", DataStore::c_Persistent), m_hashset("",
        DataStore::c_Persistent), m_decayHash(0.0), m_decayHashExtended(0.0)
  {
    setDescription("Creates the Monte Carlo decay string of a Particle and its daughters. "
                   "The MC decay string of the particle is hashed and saved as a 32bit pattern in the extra info field decayHash of the particle.  "
                   "The MC decay string of the particle + its daughters is hashed as well and saved as another 32bit pattern in the extra info field decayHashExtended of the particle.  "
                   "The mapping hash <-> MC decay string in saved in a TTree by this module.  "
                   "The 32bit pattern must be saved as a float (because our extra info field, variable manager and ntuple output only supports float) "
                   "but they just represent 32 bits of a hash!  "
                   "The MC decay string can also be stored in an analysis ROOT file using the MCDecayString NtupleTool.  "
                   "Details on the MC decay string format can be found here: `MCDecayString`");
    setPropertyFlags(c_ParallelProcessingCertified | c_TerminateInAllProcesses);
    addParam("listName", m_listName, "Particles from these ParticleList are used as input.");
    addParam("fileName", m_fileName, "Filename in which the hash strings are saved, if empty the strings are not saved",
             std::string(""));
    addParam("treeName", m_treeName, "Tree name in which the hash strings are saved", std::string("hashtable"));
    addParam("conciseString", m_useConciseString, "If set to true, the code will use a more concise format for the string.", false);
    addParam("identifiers", m_identifiers, "Identifiers used to identify particles in the concise format.",
             std::string("abcdefghijklmnopqrstuvwxyz"));
 
    m_file = nullptr;
  }
 
  void ParticleMCDecayStringModule::initialize()
  {
    m_pList.isRequired(m_listName);
 
    //This might not work for non-default names of Particle array:
    StoreArray<Particle>().isRequired();
 
    m_stringWrapperArray.registerInDataStore();
    StoreArray<Particle>().registerRelationTo(m_stringWrapperArray);
 
 
    // Initializing the output root file
    if (m_fileName != "") {
      m_file = new TFile(m_fileName.c_str(), "RECREATE");
      if (!m_file->IsOpen()) {
        B2WARNING("Could not create file " << m_fileName);
        return;
      }
 
      m_file->cd();
 
      // check if TTree with that name already exists
      if (m_file->Get(m_treeName.c_str())) {
        B2WARNING("Tree with this name already exists: " << m_fileName);
        return;
      }
 
      m_tree.registerInDataStore(m_fileName + m_treeName, DataStore::c_DontWriteOut);
      m_tree.construct(m_treeName.c_str(), "Decay Hash Map");
      m_tree->get().Branch("decayHash", &m_decayHash);
      m_tree->get().Branch("decayHashExtended", &m_decayHashExtended);
      m_tree->get().Branch("decayString", &m_decayString);
      m_tree->get().SetBasketSize("*", 1600);
      m_tree->get().SetCacheSize(100000);
    }
 
    m_hashset.registerInDataStore(m_fileName + m_treeName + "_hashset", DataStore::c_DontWriteOut);
    m_hashset.construct();
 
  }
 
  void ParticleMCDecayStringModule::event()
  {
 
    for (unsigned iParticle = 0; iParticle < m_pList->getListSize(); ++iParticle) {
      Particle* particle = m_pList->getParticle(iParticle);
 
      const std::string decayString = getMCDecayStringFromMCParticle(particle->getRelatedTo<MCParticle>());
      std::string decayStringExtended = getDecayString(*particle); //removed const to allow string to be modified to a different format.
 
      if (m_useConciseString) {convertToConciseString(decayStringExtended);}
 
      uint32_t decayHash = m_hasher(decayString);
      uint32_t decayHashExtended = m_hasher(decayStringExtended);
 
      uint64_t m_decayHashFull = decayHash;
      m_decayHashFull <<= 32;
      m_decayHashFull += decayHashExtended;
 
      // Convert unsigned int decay hash into a float keeping the same bit pattern
      assert(sizeof(float) == sizeof(uint32_t));
 
      union convert {
        uint32_t i;
        float f;
      };
      convert bitconverter;
 
      bitconverter.i = decayHash;
      m_decayHash = bitconverter.f;
      particle->addExtraInfo(c_ExtraInfoName, m_decayHash);
 
      // cppcheck doesn't like this use of union and throws warnings
      // cppcheck-suppress redundantAssignment
      bitconverter.i = decayHashExtended;
      m_decayHashExtended = bitconverter.f;
      particle->addExtraInfo(c_ExtraInfoNameExtended, m_decayHashExtended);
 
      m_decayString = decayStringExtended;
 
      StringWrapper* stringWrapper = m_stringWrapperArray.appendNew();
      particle->addRelationTo(stringWrapper);
      stringWrapper->setString(m_decayString);
 
      auto it = m_hashset->get().find(m_decayHashFull);
      if (it == m_hashset->get().end()) {
        m_hashset->get().insert(m_decayHashFull);
 
        if (m_tree.isValid()) {
          m_tree->get().Fill();
        }
      }
 
    }
  }
 
  void ParticleMCDecayStringModule::terminate()
  {
    if (!ProcHandler::parallelProcessingUsed() or ProcHandler::isOutputProcess()) {
      if (m_tree.isValid()) {
        B2INFO("Writing NTuple " << m_treeName);
        m_tree->write(m_file);
 
        const bool writeError = m_file->TestBit(TFile::kWriteError);
        if (writeError) {
          //m_file deleted first so we have a chance of closing it (though that will probably fail)
          delete m_file;
          B2FATAL("A write error occurred while saving '" << m_fileName  << "', please check if enough disk space is available.");
        }
 
        B2INFO("Closing file " << m_fileName);
        delete m_file;
      }
    }
  }
 
 
  const MCParticle* ParticleMCDecayStringModule::getInitialParticle(const MCParticle* mcP)
  {
    const MCParticle* mcPMother = mcP->getMother();
    if (mcPMother == nullptr) {
      return mcP;
    } else {
      return getInitialParticle(mcPMother);
    }
  }
 
  bool isFSP(int pdg)
  {
    switch (abs(pdg)) {
      case 211:   //pi^+
      case 321:   //K^+
      case 11:    //e
      case 12:    //nu_e
      case 13:    //mu
      case 14:    //nu_mu
      case 16:    //nu_tau
      case 22:    //gamma
      case 310:   //K_S
      case 130:   //K_L
      case 2112:  //n
      case 2212:  //p
        return true;
      default:
        return false;
    }
  }
 
  std::string ParticleMCDecayStringModule::getDecayString(const Particle& p)
  {
 
    std::string output;
    output += getDecayStringFromParticle(&p) + " | ";
    output += getMCDecayStringFromParticle(&p);
    return output;
 
  }
 
  std::string ParticleMCDecayStringModule::getDecayStringFromParticle(const Particle* p)
  {
 
    std::string output = " ";
 
    output += std::to_string(p->getPDGCode());
 
    if (not isFSP(p->getPDGCode())) {
      output += " (-->";
      for (auto daughter : p->getDaughters()) {
        output += getDecayStringFromParticle(daughter);
      }
      output += ")";
    }
 
    return output;
 
  }
 
  std::string ParticleMCDecayStringModule::getMCDecayStringFromParticle(const Particle* p)
  {
 
    std::string output;
 
    output = getMCDecayStringFromMCParticle(p->getRelatedTo<MCParticle>());
    // Some FSPs can have daughters, e.g. converted Photons and K-Shorts
    if (not isFSP(p->getPDGCode())) {
      for (auto& daughter : p->getDaughters()) {
        output += " | " + getMCDecayStringFromParticle(daughter);
      }
    }
 
    return output;
 
  }
 
  std::string ParticleMCDecayStringModule::getMCDecayStringFromMCParticle(const MCParticle* mcPMatched)
  {
 
    if (mcPMatched == nullptr)
      return "(No match)";
 
    // TODO Performance can be optimized, this mcPMother does not change during the construction
    const MCParticle* mcPMother = getInitialParticle(mcPMatched);
 
    std::string decayString = buildMCDecayString(mcPMother, mcPMatched);
 
    if (mcPMatched->getPDG() == 10022)
      return decayString + " (Virtual gamma match)";
    return decayString;
  }
 
 
  std::string ParticleMCDecayStringModule::buildMCDecayString(const MCParticle* mcPMother, const MCParticle* mcPMatched)
  {
 
    std::stringstream ss;
    ss << " ";
    if (mcPMother->getArrayIndex() == mcPMatched->getArrayIndex()) {
      ss << "^";
    }
 
    ss << mcPMother->getPDG();
 
    if (not isFSP(mcPMother->getPDG())) {
      ss << " (-->";
      for (auto daughter : mcPMother->getDaughters()) {
        ss << buildMCDecayString(daughter, mcPMatched);
      }
      ss << ")";
    }
 
    return ss.str();
  }
 
  void ParticleMCDecayStringModule::convertToConciseString(std::string& string)
  {
 
    std::vector<std::string> decayStrings;
    boost::split(decayStrings, string, boost::is_any_of("|"));
 
    if (decayStrings.empty()) {
      B2WARNING("ParticleMCDecayStringModule: unable to convert decay string to concise format.");
      return;
    }
 
    unsigned int nParticles(decayStrings.size() - 1);
    if (nParticles > m_identifiers.size()) {
      B2WARNING("ParticleMCDecayStringModule: not enough identifiers have been specified to use the concise string format:"
                << std::endl << "Number of particles in your decay mode = " << nParticles << std::endl
                << "Available identifiers: " << m_identifiers << std::endl
                << "Standard format will be used instead.");
      return;
    }
 
    //Find positions of carets in original strings, store them, and then erase them.
    std::string mode("");
    std::vector<int> caretPositions;
    for (auto& decayString : decayStrings) {
      std::string thisString(decayString);
      if ("" == mode) {
        mode = thisString;
        continue;
      }
 
      int caretPosition(thisString.find('^')); // -1 if no match.
      caretPositions.push_back(caretPosition);
      if (caretPosition > -1) {
        decayString.erase(caretPosition, 1);
      }
    }
 
    //Check if all of the decay strings are the same (except for No matches):
    std::string theDecayString("");
    for (auto thisString : decayStrings) {
      if (thisString == mode) {continue;}
 
      //last decay string does not have a space at the end, don't want this to stop a match.
      char finalChar(thisString.back());
      if (finalChar != ' ') {thisString = thisString + " ";}
 
      if (" (No match) " != thisString) {
        if ("" == theDecayString) {
          theDecayString = thisString;
        } else {
          if (theDecayString != thisString) {
            //TODO: add string format if multiple decay strings are present (e.g. pile-up events).
            return;
          }
        }
      }
    }
 
    std::string modifiedString(theDecayString);
 
    //insert identifiers in positions where carets were:
    int nStrings(caretPositions.size());
    for (int iString(0); iString < nStrings; ++iString) {
      std::string identifier(m_identifiers.substr(iString, 1));
      int insertPosition(caretPositions.at(iString));
      if (insertPosition > -1) {
        for (int jString(0); jString < iString; ++jString) {
          if (caretPositions.at(jString) > -1 && caretPositions.at(jString) <= caretPositions.at(iString)) {
            ++insertPosition;
          }
        }
        modifiedString.insert(insertPosition, identifier);
      }
    }
 
    modifiedString = mode + "|" + modifiedString;
 
    //add a list of the unmatched particles at the end of the string:
    bool noMatchStringAdded(false);
    for (int iString(0); iString < nStrings; ++iString) {
      int insertPosition(caretPositions.at(iString));
      if (-1 == insertPosition) {
        if (!noMatchStringAdded) {
          modifiedString += " | No match: ";
          noMatchStringAdded = true;
        }
        modifiedString += m_identifiers.substr(iString, 1);
      }
    }
 
    string = modifiedString;
    return;
  }
 
} // Belle2 namespace