TrackingMomentumScaleFactors.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 header.
#include <analysis/modules/TrackingSystematics/TrackingMomentumScaleFactors.h>
 
#include <framework/datastore/StoreObjPtr.h>
#include <framework/core/ModuleParam.templateDetails.h>
#include <analysis/VariableManager/Manager.h>
#include <analysis/dataobjects/ParticleList.h>
 
#include <map>
#include <TRandom.h>
#include <Math/Vector4D.h>
 
using namespace Belle2;
 
REG_MODULE(TrackingMomentumScaleFactors);
 
TrackingMomentumScaleFactorsModule::TrackingMomentumScaleFactorsModule() : Module()
{
  setDescription(
    R"DOC(Module to modify momentum of tracks from the lists. Include in your code as
 
.. code:: python
 
    mypath.add_module("TrackingMomentumScaleFactors", particleLists=['pi+:cut'], scale=0.999)
 
The module modifies the input particleLists by scaling track momenta as given by the parameter scale
         
         )DOC");
  // Parameter definitions
  addParam("particleLists", m_ParticleLists, "input particle lists");
  addParam("scale", m_scale, "scale factor to be applied to 3-momentum", nan(""));
  addParam("payloadName", m_payloadName, "ID of table used for reweighing", std::string(""));
  addParam("scalingFactorName", m_scalingFactorName, "Label for the scale factor in the look up table", std::string(""));
  addParam("smearingFactorName", m_smearingFactorName, "Label for the smearing factor in the look up table", std::string(""));
}
 
void TrackingMomentumScaleFactorsModule::initialize()
{
  if (!isnan(m_scale) && !m_payloadName.empty()) {
    B2FATAL("It's not allowed to provide both a valid value for the scale parameter and a non-empty table name. Please decide for one of the two options!");
  } else if (isnan(m_scale) && m_payloadName.empty()) {
    B2FATAL("Neither a valid value for the scale parameter nor a non-empty table name was provided. Please set (exactly) one of the two options!");
  } else if (!m_scalingFactorName.empty() && !m_smearingFactorName.empty()) {
    B2FATAL("It's not allowed to provide both a valid value for the scalingFactorName and smearingFactorName. Please set (exactly) one of the two options!");
  } else if (!m_payloadName.empty()) {
    m_ParticleWeightingLookUpTable = std::make_unique<DBObjPtr<ParticleWeightingLookUpTable>>(m_payloadName);
 
    std::vector<std::string> variables =  Variable::Manager::Instance().resolveCollections((
                                            *m_ParticleWeightingLookUpTable.get())->getAxesNames());
    for (const auto& i_variable : variables) {
      const Variable::Manager::Var* var = Variable::Manager::Instance().getVariable(i_variable);
      if (!var) {
        B2FATAL("Variable '" << i_variable << "' is not available in Variable::Manager!");
      }
    }
  }
}
 
void TrackingMomentumScaleFactorsModule::event()
{
  for (auto& iList : m_ParticleLists) {
    StoreObjPtr<ParticleList> particleList(iList);
 
    //check particle List exists and has particles
    if (!particleList) {
      B2ERROR("ParticleList " << iList << " not found");
      continue;
    }
 
    size_t nPart = particleList->getListSize();
    for (size_t iPart = 0; iPart < nPart; iPart++) {
      auto particle = particleList->getParticle(iPart);
      setMomentumScalingFactor(particle);
    }
  }
}
 
 
// Getting LookUp info for given particle in given event
double TrackingMomentumScaleFactorsModule::getScalingFactor(Particle* particle)
{
  std::vector<std::string> variables =  Variable::Manager::Instance().resolveCollections((
                                          *m_ParticleWeightingLookUpTable.get())->getAxesNames());
 
  std::map<std::string, double> values;
  for (const auto& i_variable : variables) {
    const Variable::Manager::Var* var = Variable::Manager::Instance().getVariable(i_variable);
    double value = std::get<double>(var->function(particle));
    values.insert(std::make_pair(i_variable, value));
  }
 
  WeightInfo info = (*m_ParticleWeightingLookUpTable.get())->getInfo(values);
  for (const auto& entry : info) {
    particle->writeExtraInfo(m_payloadName + "_" + entry.first, entry.second);
  }
 
  return particle->getExtraInfo(m_payloadName + "_" + m_scalingFactorName);
}
 
 
 
double TrackingMomentumScaleFactorsModule::getSmearingFactor(Particle* particle)
{
  std::vector<std::string> variables =  Variable::Manager::Instance().resolveCollections((
                                          *m_ParticleWeightingLookUpTable.get())->getAxesNames());
 
  std::map<std::string, double> values;
  for (const auto& i_variable : variables) {
    const Variable::Manager::Var* var = Variable::Manager::Instance().getVariable(i_variable);
    double value = std::get<double>(var->function(particle));
    values.insert(std::make_pair(i_variable, value));
  }
 
  WeightInfo info = (*m_ParticleWeightingLookUpTable.get())->getInfo(values);
  for (const auto& entry : info) {
    particle->writeExtraInfo(m_payloadName + "_" + entry.first, gRandom->Gaus(1, entry.second));
  }
  return particle->getExtraInfo(m_payloadName + "_" + m_smearingFactorName);
}
 
 
 
void TrackingMomentumScaleFactorsModule::setMomentumScalingFactor(Particle* particle)
{
  if (particle->getParticleSource() == Particle::EParticleSourceObject::c_Composite or
      particle->getParticleSource() == Particle::EParticleSourceObject::c_V0) {
    for (auto daughter : particle->getDaughters()) {
      setMomentumScalingFactor(daughter);
    }
    double px = 0;
    double py = 0;
    double pz = 0;
    double E = 0;
    for (auto daughter : particle->getDaughters()) {
      px += daughter->getPx();
      py += daughter->getPy();
      pz += daughter->getPz();
      E  += daughter->getEnergy();
    }
    const ROOT::Math::PxPyPzEVector vec(px, py, pz, E);
    particle->set4Vector(vec);
  } else if (particle->getParticleSource() == Particle::EParticleSourceObject::c_Track) {
    if (!isnan(m_scale)) {
      particle->setMomentumScalingFactor(m_scale);
    } else if (!m_scalingFactorName.empty()) {
      particle->setMomentumScalingFactor(getScalingFactor(particle));
    } else if (!m_smearingFactorName.empty()) {
      particle->setMomentumSmearingFactor(getSmearingFactor(particle));
    }
  }
 
 
}