Root/src/RootParticleWriter.cpp

0001 // This file is part of the ACTS project.
0002 //
0003 // Copyright (C) 2016 CERN for the benefit of the ACTS project
0004 //
0005 // This Source Code Form is subject to the terms of the Mozilla Public
0006 // License, v. 2.0. If a copy of the MPL was not distributed with this
0007 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
0008
0009 #include "ActsExamples/Io/Root/RootParticleWriter.hpp"
0010
0011 #include "Acts/Definitions/TrackParametrization.hpp"
0012 #include "Acts/Definitions/Units.hpp"
0013 #include "Acts/Propagator/Propagator.hpp"
0014 #include "Acts/Propagator/SympyStepper.hpp"
0015 #include "Acts/Surfaces/PerigeeSurface.hpp"
0016 #include "Acts/Surfaces/Surface.hpp"
0017 #include "Acts/Utilities/Helpers.hpp"
0018 #include "Acts/Utilities/VectorHelpers.hpp"
0019 #include "ActsExamples/EventData/SimParticle.hpp"
0020 #include "ActsExamples/Framework/AlgorithmContext.hpp"
0021
0022 #include <cstdint>
0023 #include <ios>
0024 #include <stdexcept>
0025
0026 #include <TFile.h>
0027 #include <TTree.h>
0028
0029 namespace ActsExamples {
0030
0031 RootParticleWriter::RootParticleWriter(const RootParticleWriter::Config& cfg,
0032                                        Acts::Logging::Level lvl)
0033     : WriterT(cfg.inputParticles, "RootParticleWriter", lvl), m_cfg(cfg) {
0034   // inputParticles is already checked by base constructor
0035   if (m_cfg.filePath.empty()) {
0036     throw std::invalid_argument("Missing file path");
0037   }
0038   if (m_cfg.treeName.empty()) {
0039     throw std::invalid_argument("Missing tree name");
0040   }
0041
0042   // open root file and create the tree
0043   m_outputFile = TFile::Open(m_cfg.filePath.c_str(), m_cfg.fileMode.c_str());
0044   if (m_outputFile == nullptr) {
0045     throw std::ios_base::failure("Could not open '" + m_cfg.filePath + "'");
0046   }
0047   m_outputFile->cd();
0048   m_outputTree = new TTree(m_cfg.treeName.c_str(), m_cfg.treeName.c_str());
0049   if (m_outputTree == nullptr) {
0050     throw std::bad_alloc();
0051   }
0052
0053   // setup the branches
0054   m_outputTree->Branch("event_id", &m_eventId);
0055   m_outputTree->Branch("particle_hash", &m_particleHash);
0056   m_outputTree->Branch("particle_type", &m_particleType);
0057   m_outputTree->Branch("process", &m_process);
0058   m_outputTree->Branch("vx", &m_vx);
0059   m_outputTree->Branch("vy", &m_vy);
0060   m_outputTree->Branch("vz", &m_vz);
0061   m_outputTree->Branch("vt", &m_vt);
0062   m_outputTree->Branch("px", &m_px);
0063   m_outputTree->Branch("py", &m_py);
0064   m_outputTree->Branch("pz", &m_pz);
0065   m_outputTree->Branch("m", &m_m);
0066   m_outputTree->Branch("q", &m_q);
0067   m_outputTree->Branch("eta", &m_eta);
0068   m_outputTree->Branch("phi", &m_phi);
0069   m_outputTree->Branch("pt", &m_pt);
0070   m_outputTree->Branch("p", &m_p);
0071   m_outputTree->Branch("q_over_p", &m_qop);
0072   m_outputTree->Branch("theta", &m_theta);
0073   m_outputTree->Branch("vertex_primary", &m_vertexPrimary);
0074   m_outputTree->Branch("vertex_secondary", &m_vertexSecondary);
0075   m_outputTree->Branch("particle", &m_particle);
0076   m_outputTree->Branch("generation", &m_generation);
0077   m_outputTree->Branch("sub_particle", &m_subParticle);
0078
0079   if (m_cfg.writeHelixParameters) {
0080     m_outputTree->Branch("perigee_d0", &m_perigeeD0);
0081     m_outputTree->Branch("perigee_z0", &m_perigeeZ0);
0082     m_outputTree->Branch("perigee_phi", &m_perigeePhi);
0083     m_outputTree->Branch("perigee_theta", &m_perigeeTheta);
0084     m_outputTree->Branch("perigee_q_over_p", &m_perigeeQop);
0085     m_outputTree->Branch("perigee_p", &m_perigeeP);
0086     m_outputTree->Branch("perigee_px", &m_perigeePx);
0087     m_outputTree->Branch("perigee_py", &m_perigeePy);
0088     m_outputTree->Branch("perigee_pz", &m_perigeePz);
0089     m_outputTree->Branch("perigee_eta", &m_perigeeEta);
0090     m_outputTree->Branch("perigee_pt", &m_perigeePt);
0091   }
0092
0093   m_outputTree->Branch("e_loss", &m_eLoss);
0094   m_outputTree->Branch("total_x0", &m_pathInX0);
0095   m_outputTree->Branch("total_l0", &m_pathInL0);
0096   m_outputTree->Branch("number_of_hits", &m_numberOfHits);
0097   m_outputTree->Branch("outcome", &m_outcome);
0098 }
0099
0100 RootParticleWriter::~RootParticleWriter() {
0101   if (m_outputFile != nullptr) {
0102     m_outputFile->Close();
0103   }
0104 }
0105
0106 ProcessCode RootParticleWriter::finalize() {
0107   m_outputFile->cd();
0108   m_outputTree->Write();
0109   m_outputFile->Close();
0110
0111   ACTS_INFO("Wrote particles to tree '" << m_cfg.treeName << "' in '"
0112                                         << m_cfg.filePath << "'");
0113
0114   return ProcessCode::SUCCESS;
0115 }
0116
0117 ProcessCode RootParticleWriter::writeT(const AlgorithmContext& ctx,
0118                                        const SimParticleContainer& particles) {
0119   // ensure exclusive access to tree/file while writing
0120   std::lock_guard<std::mutex> lock(m_writeMutex);
0121
0122   m_eventId = ctx.eventNumber;
0123   for (const auto& particle : particles) {
0124     m_particleHash.push_back(particle.particleId().hash());
0125     m_particleType.push_back(particle.pdg());
0126     m_process.push_back(static_cast<std::uint32_t>(particle.process()));
0127     // position
0128     m_vx.push_back(Acts::clampValue<float>(particle.fourPosition().x() /
0129                                            Acts::UnitConstants::mm));
0130     m_vy.push_back(Acts::clampValue<float>(particle.fourPosition().y() /
0131                                            Acts::UnitConstants::mm));
0132     m_vz.push_back(Acts::clampValue<float>(particle.fourPosition().z() /
0133                                            Acts::UnitConstants::mm));
0134     m_vt.push_back(Acts::clampValue<float>(particle.fourPosition().w() /
0135                                            Acts::UnitConstants::mm));
0136
0137     // particle constants
0138     if (!std::isfinite(particle.mass()) || !std::isfinite(particle.charge())) {
0139       ACTS_WARNING("Particle mass or charge is not finite, can't write it");
0140     }
0141
0142     m_m.push_back(
0143         Acts::clampValue<float>(particle.mass() / Acts::UnitConstants::GeV));
0144     m_q.push_back(
0145         Acts::clampValue<float>(particle.charge() / Acts::UnitConstants::e));
0146     // decoded barcode components
0147     m_vertexPrimary.push_back(particle.particleId().vertexPrimary());
0148     m_vertexSecondary.push_back(particle.particleId().vertexSecondary());
0149     m_particle.push_back(particle.particleId().particle());
0150     m_generation.push_back(particle.particleId().generation());
0151     m_subParticle.push_back(particle.particleId().subParticle());
0152
0153     m_eLoss.push_back(Acts::clampValue<float>(particle.energyLoss() /
0154                                               Acts::UnitConstants::GeV));
0155     m_pathInX0.push_back(
0156         Acts::clampValue<float>(particle.pathInX0() / Acts::UnitConstants::mm));
0157     m_pathInL0.push_back(
0158         Acts::clampValue<float>(particle.pathInL0() / Acts::UnitConstants::mm));
0159     m_numberOfHits.push_back(particle.numberOfHits());
0160     m_outcome.push_back(static_cast<std::uint32_t>(particle.outcome()));
0161
0162     // momentum
0163     const auto p = particle.absoluteMomentum() / Acts::UnitConstants::GeV;
0164     m_p.push_back(Acts::clampValue<float>(p));
0165     m_px.push_back(Acts::clampValue<float>(p * particle.direction().x()));
0166     m_py.push_back(Acts::clampValue<float>(p * particle.direction().y()));
0167     m_pz.push_back(Acts::clampValue<float>(p * particle.direction().z()));
0168     // derived kinematic quantities
0169     m_eta.push_back(Acts::clampValue<float>(
0170         Acts::VectorHelpers::eta(particle.direction())));
0171     m_pt.push_back(Acts::clampValue<float>(
0172         p * Acts::VectorHelpers::perp(particle.direction())));
0173     m_phi.push_back(Acts::clampValue<float>(
0174         Acts::VectorHelpers::phi(particle.direction())));
0175     m_theta.push_back(Acts::clampValue<float>(
0176         Acts::VectorHelpers::theta(particle.direction())));
0177     m_qop.push_back(Acts::clampValue<float>(
0178         particle.qOverP() * Acts::UnitConstants::GeV / Acts::UnitConstants::e));
0179
0180     if (!m_cfg.writeHelixParameters) {
0181       // done with this particle
0182       continue;
0183     }
0184
0185     // Perigee surface at configured reference point
0186     auto pSurface =
0187         Acts::Surface::makeShared<Acts::PerigeeSurface>(m_cfg.referencePoint);
0188
0189     // Start from truth curvilinear parameters (direction, q/p)
0190     const Acts::Vector3 startDir = particle.direction();  // unit vector
0191     const auto qOverP = particle.qOverP();                // ACTS units
0192     auto intersection =
0193         pSurface
0194             ->intersect(ctx.geoContext, particle.position(), startDir,
0195                         Acts::BoundaryTolerance::Infinite())
0196             .closest();
0197
0198     // Neutral particles have no helix -> linearly extrapolate to perigee
0199     if (particle.charge() == 0) {
0200       ACTS_WARNING(
0201           "Particle has zero charge, linearly extrapolating to perigee");
0202       // Initialize the truth particle info
0203       auto perigeeD0 = NaNfloat;
0204       auto perigeeZ0 = NaNfloat;
0205
0206       const auto position = intersection.position();
0207
0208       // get the truth perigee parameter
0209       auto lpResult =
0210           pSurface->globalToLocal(ctx.geoContext, position, startDir);
0211       if (lpResult.ok()) {
0212         perigeeD0 = lpResult.value()[Acts::BoundIndices::eBoundLoc0];
0213         perigeeZ0 = lpResult.value()[Acts::BoundIndices::eBoundLoc1];
0214       } else {
0215         ACTS_ERROR("Global to local transformation did not succeed.");
0216       }
0217       // truth parameters at perigee are the same as at production vertex
0218       m_perigeePhi.push_back(Acts::clampValue<float>(particle.phi()));
0219       m_perigeeTheta.push_back(Acts::clampValue<float>(particle.theta()));
0220       m_perigeeQop.push_back(Acts::clampValue<float>(
0221           qOverP * Acts::UnitConstants::GeV / Acts::UnitConstants::e));
0222       m_perigeeP.push_back(Acts::clampValue<float>(particle.absoluteMomentum() /
0223                                                    Acts::UnitConstants::GeV));
0224       m_perigeePx.push_back(Acts::clampValue<float>(m_p.back() * startDir.x()));
0225       m_perigeePy.push_back(Acts::clampValue<float>(m_p.back() * startDir.y()));
0226       m_perigeePz.push_back(Acts::clampValue<float>(m_p.back() * startDir.z()));
0227       m_perigeeEta.push_back(Acts::clampValue<float>(
0228           Acts::VectorHelpers::eta(particle.direction())));
0229       m_perigeePt.push_back(Acts::clampValue<float>(
0230           m_p.back() * Acts::VectorHelpers::perp(particle.direction())));
0231
0232       // Push the extrapolated parameters
0233       m_perigeeD0.push_back(
0234           Acts::clampValue<float>(perigeeD0 / Acts::UnitConstants::mm));
0235       m_perigeeZ0.push_back(
0236           Acts::clampValue<float>(perigeeZ0 / Acts::UnitConstants::mm));
0237       continue;
0238     }
0239
0240     // Charged particles: propagate helix to perigee
0241     // Build a propagator and propagate the *truth parameters* to the
0242     // perigee Stepper + propagator
0243     using Stepper = Acts::SympyStepper;
0244     Stepper stepper(m_cfg.bField);
0245     using PropagatorT = Acts::Propagator<Stepper>;
0246     auto propagator = std::make_shared<PropagatorT>(stepper);
0247
0248     Acts::BoundTrackParameters startParams =
0249         Acts::BoundTrackParameters::createCurvilinear(
0250             particle.fourPosition(), startDir, qOverP, std::nullopt,
0251             Acts::ParticleHypothesis::pion());
0252
0253     // Propagation options (need event contexts)
0254     using PropOptions = PropagatorT::Options<>;
0255     PropOptions pOptions(ctx.geoContext, ctx.magFieldContext);
0256
0257     // Choose propagation direction based on the closest intersection
0258     pOptions.direction =
0259         Acts::Direction::fromScalarZeroAsPositive(intersection.pathLength());
0260
0261     // Do the propagation to the perigee surface
0262     auto propRes = propagator->propagate(startParams, *pSurface, pOptions);
0263     if (!propRes.ok() || !propRes->endParameters.has_value()) {
0264       ACTS_ERROR("Propagation to perigee surface failed.");
0265       m_perigeePhi.push_back(NaNfloat);
0266       m_perigeeTheta.push_back(NaNfloat);
0267       m_perigeeQop.push_back(NaNfloat);
0268       m_perigeeD0.push_back(NaNfloat);
0269       m_perigeeZ0.push_back(NaNfloat);
0270       m_perigeeP.push_back(NaNfloat);
0271       m_perigeePx.push_back(NaNfloat);
0272       m_perigeePy.push_back(NaNfloat);
0273       m_perigeePz.push_back(NaNfloat);
0274       m_perigeeEta.push_back(NaNfloat);
0275       m_perigeePt.push_back(NaNfloat);
0276       continue;
0277     }
0278     const Acts::BoundTrackParameters& atPerigee = *propRes->endParameters;
0279
0280     // By construction, atPerigee is *bound on the perigee surface*.
0281     // Its parameter vector is [loc0, loc1, phi, theta, q/p, t]
0282     const auto& perigee_pars = atPerigee.parameters();
0283
0284     const auto perigeeD0 = perigee_pars[Acts::BoundIndices::eBoundLoc0];
0285     const auto perigeeZ0 = perigee_pars[Acts::BoundIndices::eBoundLoc1];
0286
0287     // truth phi;theta;q/p *at the perigee*,
0288     const auto perigeePhi = perigee_pars[Acts::BoundIndices::eBoundPhi];
0289     const auto perigeeTheta = perigee_pars[Acts::BoundIndices::eBoundTheta];
0290     const auto perigeeQop = perigee_pars[Acts::BoundIndices::eBoundQOverP];
0291
0292     m_perigeePhi.push_back(Acts::clampValue<float>(perigeePhi));
0293     m_perigeeTheta.push_back(Acts::clampValue<float>(perigeeTheta));
0294     m_perigeeQop.push_back(Acts::clampValue<float>(
0295         perigeeQop * Acts::UnitConstants::GeV / Acts::UnitConstants::e));
0296     // update p, px, py, pz, eta, pt
0297     const auto perigeeP =
0298         atPerigee.absoluteMomentum() / Acts::UnitConstants::GeV;
0299     m_perigeeP.push_back(Acts::clampValue<float>(perigeeP));
0300     const auto dir = atPerigee.direction();
0301     m_perigeePx.push_back(Acts::clampValue<float>(perigeeP * dir.x()));
0302     m_perigeePy.push_back(Acts::clampValue<float>(perigeeP * dir.y()));
0303     m_perigeePz.push_back(Acts::clampValue<float>(perigeeP * dir.z()));
0304     m_perigeeEta.push_back(Acts::clampValue<float>(
0305         Acts::VectorHelpers::eta(atPerigee.direction())));
0306     m_perigeePt.push_back(Acts::clampValue<float>(
0307         perigeeP * Acts::VectorHelpers::perp(atPerigee.direction())));
0308
0309     // Push the perigee parameters
0310     m_perigeeD0.push_back(
0311         Acts::clampValue<float>(perigeeD0 / Acts::UnitConstants::mm));
0312     m_perigeeZ0.push_back(
0313         Acts::clampValue<float>(perigeeZ0 / Acts::UnitConstants::mm));
0314   }
0315
0316   m_outputTree->Fill();
0317
0318   m_particleHash.clear();
0319   m_particleType.clear();
0320   m_process.clear();
0321   m_vx.clear();
0322   m_vy.clear();
0323   m_vz.clear();
0324   m_vt.clear();
0325   m_p.clear();
0326   m_px.clear();
0327   m_py.clear();
0328   m_pz.clear();
0329   m_m.clear();
0330   m_q.clear();
0331   m_eta.clear();
0332   m_phi.clear();
0333   m_pt.clear();
0334   m_theta.clear();
0335   m_qop.clear();
0336   m_vertexPrimary.clear();
0337   m_vertexSecondary.clear();
0338   m_particle.clear();
0339   m_generation.clear();
0340   m_subParticle.clear();
0341   m_eLoss.clear();
0342   m_numberOfHits.clear();
0343   m_outcome.clear();
0344   m_pathInX0.clear();
0345   m_pathInL0.clear();
0346
0347   if (m_cfg.writeHelixParameters) {
0348     m_perigeeD0.clear();
0349     m_perigeeZ0.clear();
0350     m_perigeePhi.clear();
0351     m_perigeeTheta.clear();
0352     m_perigeeQop.clear();
0353     m_perigeeP.clear();
0354     m_perigeePx.clear();
0355     m_perigeePy.clear();
0356     m_perigeePz.clear();
0357     m_perigeeEta.clear();
0358     m_perigeePt.clear();
0359   }
0360
0361   return ProcessCode::SUCCESS;
0362 }
0363
0364 }  // namespace ActsExamples