algorithms/pid_lut/PIDLookup.cc

0001 // SPDX-License-Identifier: LGPL-3.0-or-later
0002 // Copyright (C) 2024, Nathan Brei, Dmitry Kalinkin
0003
0004 #include <algorithms/service.h>
0005 #include <edm4eic/EDM4eicVersion.h>
0006 #include <edm4eic/MCRecoParticleAssociationCollection.h>
0007 #include <edm4eic/ReconstructedParticleCollection.h>
0008 #include <edm4hep/MCParticleCollection.h>
0009 #include <edm4hep/Vector3f.h>
0010 #include <edm4hep/utils/vector_utils.h>
0011 #include <podio/detail/Link.h>
0012 #include <podio/detail/LinkCollectionImpl.h>
0013 #include <cmath>
0014 #include <exception>
0015 #include <gsl/pointers>
0016 #include <memory>
0017 #include <random>
0018 #include <stdexcept>
0019 #include <vector>
0020
0021 #include "algorithms/pid_lut/PIDLookup.h"
0022 #include "algorithms/pid_lut/PIDLookupConfig.h"
0023 #include "services/pid_lut/PIDLookupTableSvc.h"
0024
0025 namespace eicrecon {
0026
0027 void PIDLookup::init() {
0028
0029   try {
0030     m_system = m_detector->constant<int32_t>(m_cfg.system);
0031   } catch (const std::exception& e) {
0032     error("Failed to get {} from the detector: {}", m_cfg.system, e.what());
0033     throw std::runtime_error("Failed to get requested ID from the detector");
0034   }
0035
0036   auto& serviceSvc = algorithms::ServiceSvc::instance();
0037   auto* lut_svc    = serviceSvc.service<PIDLookupTableSvc>("PIDLookupTableSvc");
0038
0039   m_lut = lut_svc->load(m_cfg.filename,
0040                         {
0041                             .pdg_values                   = m_cfg.pdg_values,
0042                             .charge_values                = m_cfg.charge_values,
0043                             .momentum_edges               = m_cfg.momentum_edges,
0044                             .polar_edges                  = m_cfg.polar_edges,
0045                             .azimuthal_binning            = m_cfg.azimuthal_binning,
0046                             .azimuthal_bin_centers_in_lut = m_cfg.azimuthal_bin_centers_in_lut,
0047                             .momentum_bin_centers_in_lut  = m_cfg.momentum_bin_centers_in_lut,
0048                             .polar_bin_centers_in_lut     = m_cfg.polar_bin_centers_in_lut,
0049                             .use_radians                  = m_cfg.use_radians,
0050                             .missing_electron_prob        = m_cfg.missing_electron_prob,
0051                         });
0052   if (m_lut == nullptr) {
0053     throw std::runtime_error("LUT not available");
0054   }
0055 }
0056
0057 void PIDLookup::process(const Input& input, const Output& output) const {
0058   const auto [headers, recoparts_in, partassocs_in] = input;
0059 #if EDM4EIC_BUILD_VERSION >= EDM4EIC_VERSION(8, 7, 0)
0060   auto [recoparts_out, partlinks_out, partassocs_out, partids_out] = output;
0061 #else
0062   auto [recoparts_out, partassocs_out, partids_out] = output;
0063 #endif
0064
0065   // local random generator
0066   auto seed = m_uid.getUniqueID(*headers, name());
0067   std::default_random_engine generator(seed);
0068   std::uniform_real_distribution<double> uniform;
0069
0070   for (const auto& recopart_without_pid : *recoparts_in) {
0071     auto recopart = recopart_without_pid.clone();
0072
0073     // Find MCParticle from associations and propagate the relevant ones further
0074     auto best_assoc = edm4eic::MCRecoParticleAssociation::makeEmpty();
0075     for (auto assoc_in : *partassocs_in) {
0076       if (assoc_in.getRec() == recopart_without_pid) {
0077         if ((not best_assoc.isAvailable()) || (best_assoc.getWeight() < assoc_in.getWeight())) {
0078           best_assoc = assoc_in;
0079         }
0080 #if EDM4EIC_BUILD_VERSION >= EDM4EIC_VERSION(8, 7, 0)
0081         auto link_out = partlinks_out->create();
0082         link_out.setFrom(recopart);
0083         link_out.setTo(assoc_in.getSim());
0084         link_out.setWeight(assoc_in.getWeight());
0085 #endif
0086         auto assoc_out = assoc_in.clone();
0087         assoc_out.setRec(recopart);
0088         partassocs_out->push_back(assoc_out);
0089       }
0090     }
0091     if (not best_assoc.isAvailable()) {
0092       recoparts_out->push_back(recopart);
0093       continue;
0094     }
0095
0096     edm4hep::MCParticle mcpart = best_assoc.getSim();
0097
0098     int true_pdg    = mcpart.getPDG();
0099     int true_charge = mcpart.getCharge();
0100     int charge      = recopart.getCharge();
0101     double momentum = edm4hep::utils::magnitude(recopart.getMomentum());
0102
0103     double theta = edm4hep::utils::anglePolar(recopart.getMomentum()) / M_PI * 180.;
0104     double phi   = edm4hep::utils::angleAzimuthal(recopart.getMomentum()) / M_PI * 180.;
0105
0106     trace("lookup for true_pdg={}, true_charge={}, momentum={:.2f} GeV, polar={:.2f}, "
0107           "aziumthal={:.2f}",
0108           true_pdg, true_charge, momentum, theta, phi);
0109     const auto* entry = m_lut->Lookup(true_pdg, true_charge, momentum, theta, phi);
0110
0111     int identified_pdg = 0; // unknown
0112
0113     if ((entry != nullptr) && ((entry->prob_electron != 0.) || (entry->prob_pion != 0.) ||
0114                                (entry->prob_kaon != 0.) || (entry->prob_proton != 0.))) {
0115       double random_unit_interval = uniform(generator);
0116
0117       trace("entry with e:pi:K:P={}:{}:{}:{}", entry->prob_electron, entry->prob_pion,
0118             entry->prob_kaon, entry->prob_proton);
0119
0120       recopart.addToParticleIDs(
0121           partids_out->create(m_system,                                // std::int32_t type
0122                               std::copysign(11, -charge),              // std::int32_t PDG
0123                               0,                                       // std::int32_t algorithmType
0124                               static_cast<float>(entry->prob_electron) // float likelihood
0125                               ));
0126       recopart.addToParticleIDs(
0127           partids_out->create(m_system,                            // std::int32_t type
0128                               std::copysign(211, charge),          // std::int32_t PDG
0129                               0,                                   // std::int32_t algorithmType
0130                               static_cast<float>(entry->prob_pion) // float likelihood
0131                               ));
0132       recopart.addToParticleIDs(
0133           partids_out->create(m_system,                            // std::int32_t type
0134                               std::copysign(321, charge),          // std::int32_t PDG
0135                               0,                                   // std::int32_t algorithmType
0136                               static_cast<float>(entry->prob_kaon) // float likelihood
0137                               ));
0138       recopart.addToParticleIDs(
0139           partids_out->create(m_system,                              // std::int32_t type
0140                               std::copysign(2212, charge),           // std::int32_t PDG
0141                               0,                                     // std::int32_t algorithmType
0142                               static_cast<float>(entry->prob_proton) // float likelihood
0143                               ));
0144
0145       if (random_unit_interval < entry->prob_electron) {
0146         identified_pdg = 11; // electron
0147         recopart.setParticleIDUsed((*partids_out)[partids_out->size() - 4]);
0148       } else if (random_unit_interval < (entry->prob_electron + entry->prob_pion)) {
0149         identified_pdg = 211; // pion
0150         recopart.setParticleIDUsed((*partids_out)[partids_out->size() - 3]);
0151       } else if (random_unit_interval <
0152                  (entry->prob_electron + entry->prob_pion + entry->prob_kaon)) {
0153         identified_pdg = 321; // kaon
0154         recopart.setParticleIDUsed((*partids_out)[partids_out->size() - 2]);
0155       } else if (random_unit_interval < (entry->prob_electron + entry->prob_pion +
0156                                          entry->prob_kaon + entry->prob_proton)) {
0157         identified_pdg = 2212; // proton
0158         recopart.setParticleIDUsed((*partids_out)[partids_out->size() - 1]);
0159       }
0160     }
0161
0162     if (identified_pdg != 0) {
0163       recopart.setPDG(std::copysign(identified_pdg, (identified_pdg == 11) ? -charge : charge));
0164       recopart.setMass(m_particleSvc.particle(identified_pdg).mass);
0165       recopart.setEnergy(std::hypot(momentum, m_particleSvc.particle(identified_pdg).mass));
0166     }
0167
0168     if (identified_pdg != 0) {
0169       trace("randomized PDG is {}", recopart.getPDG());
0170     }
0171
0172     recoparts_out->push_back(recopart);
0173   }
0174 }
0175
0176 } // namespace eicrecon