ParticleSelectorModule.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.                  *
 **************************************************************************/
 
// Own include
#include <analysis/modules/ParticleSelector/ParticleSelectorModule.h>
 
// framework aux
#include <framework/logging/Logger.h>
 
// dataobjects
#include <analysis/dataobjects/Particle.h>
 
using namespace std;
 
namespace Belle2 {
  //-----------------------------------------------------------------
  //                 Register module
  //-----------------------------------------------------------------
 
  REG_MODULE(ParticleSelector)
 
  //-----------------------------------------------------------------
  //                 Implementation
  //-----------------------------------------------------------------
 
  ParticleSelectorModule::ParticleSelectorModule() : Module()
  {
    setDescription("Removes Particles from given ParticleList that do not pass specified selection criteria.");
 
    setPropertyFlags(c_ParallelProcessingCertified);
 
    addParam("decayString", m_decayString,
             "Input ParticleList name (see :ref:`DecayString`).");
 
    addParam("cut", m_cutParameter,
             "Selection criteria to be applied, see `cut_strings_selections`",
             std::string(""));
  }
 
  void ParticleSelectorModule::initialize()
  {
    // obtain the input and output particle lists from the decay string
    bool valid = m_decaydescriptor.init(m_decayString);
    if (!valid)
      B2ERROR("ParticleSelectorModule::initialize Invalid input DecayString: " << m_decayString);
 
    int nProducts = m_decaydescriptor.getNDaughters();
    if (nProducts > 0)
      B2ERROR("ParticleSelectorModule::initialize Invalid input DecayString " << m_decayString
              << ". DecayString should not contain any daughters, only the mother particle.");
 
    // Mother particle
    const DecayDescriptorParticle* mother = m_decaydescriptor.getMother();
 
    const int pdgCode = mother->getPDGCode();
    string listLabel = mother->getLabel();
    m_listName = mother->getFullName();
    // Some labels are reserved for the particle loader which loads all particles of the corresponding type.
    // If people applied cuts on these particle lists, very dangerous bugs could be introduced.
    // An exception is made for the gamma:all list. This can be limited to photons from the ECL only.
    if (Const::finalStateParticlesSet.contains(Const::ParticleType(abs(pdgCode))) and listLabel == "all"
        and not(abs(pdgCode) == Const::photon.getPDGCode() and m_cutParameter == "isFromECL")) {
      B2FATAL("You are trying to apply a cut on the list " << m_listName <<
              " but the label 'all' is protected for lists of final-state particles." <<
              " It could introduce *very* dangerous bugs.");
    } else if (listLabel == "MC" or listLabel == "V0") {
      // the labels MC and V0 are also protected
      B2FATAL("You are trying to apply a cut on the list " << m_listName <<
              " but the label " << listLabel << " is protected and can not be reduced.");
    }
 
    m_particleList.isRequired(m_listName);
 
    m_cut = Variable::Cut::compile(m_cutParameter);
 
    B2INFO("ParticleSelector: " << m_listName);
    B2INFO("   -> With cuts  : " << m_cutParameter);
  }
 
  void ParticleSelectorModule::event()
  {
    // loop over list only if cuts should be applied
    if (!m_cutParameter.empty()) {
      std::vector<unsigned int> toRemove;
      unsigned int n = m_particleList->getListSize();
      for (unsigned i = 0; i < n; i++) {
        const Particle* part = m_particleList->getParticle(i);
        if (!m_cut->check(part)) toRemove.push_back(part->getArrayIndex());
      }
      m_particleList->removeParticles(toRemove);
    }
  }
} // end Belle2 namespace