KalmanFilterTrajectoryFitter_module.cc

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/// \class KalmanFilterTrajectoryFitter
///
/// \brief Producer for fitting Trajectories and TrackTrajectories using TrackKalmanFitter.
///
/// \author G. Cerati
///

#include "art/Framework/Core/EDProducer.h"
#include "art/Framework/Core/ModuleMacros.h"
#include "art/Framework/Principal/Event.h"
#include "art/Framework/Principal/Handle.h"

#include "canvas/Utilities/InputTag.h"
#include "fhiclcpp/types/Atom.h"
#include "fhiclcpp/types/Sequence.h"
#include "fhiclcpp/types/Table.h"

#include "lardata/DetectorInfoServices/DetectorPropertiesService.h"
#include "lardata/RecoObjects/TrackStatePropagator.h"
#include "lardataobj/MCBase/MCTrack.h"
#include "lardataobj/RecoBase/Hit.h"
#include "lardataobj/RecoBase/SpacePoint.h"
#include "lardataobj/RecoBase/Track.h"
#include "lardataobj/RecoBase/TrackHitMeta.h"
#include "larreco/RecoAlg/TrackKalmanFitter.h"
#include "larreco/RecoAlg/TrackMomentumCalculator.h"
#include "larreco/TrackFinder/TrackMaker.h"

#include <memory>

namespace trkf {

  class KalmanFilterTrajectoryFitter : public art::EDProducer {
  public:
    struct Inputs {
      using Name = fhicl::Name;
      using Comment = fhicl::Comment;
      fhicl::Atom<art::InputTag> inputTrajectoryLabel{
        Name("inputTrajectoryLabel"),
        Comment("Label of recob::Trajectory or recob::TrackTrajectory Collection to be fit")};
      fhicl::Atom<bool> isTrackTrajectory{
        Name("isTrackTrajectory"),
        Comment("If true, we assume the input collection is made of recob::TrackTrajectory "
                "objects, otherwise of recob::Trajectory objects.")};
      fhicl::Atom<art::InputTag> inputMCLabel{
        Name("inputMCLabel"),
        Comment("Label of sim::MCTrack Collection to be used for initial momentum estimate. Used "
                "only if momFromMC is set to true.")};
    };

    struct Options {
      using Name = fhicl::Name;
      using Comment = fhicl::Comment;
      fhicl::Atom<bool> pFromLength{Name("momFromLength"),
                                    Comment("Flag used to get initial momentum estimate from "
                                            "trkf::TrackMomentumCalculator::GetTrackMomentum().")};
      fhicl::Atom<bool> pFromMC{
        Name("momFromMC"),
        Comment("Flag used to get initial momentum estimate from inputMCLabel collection.")};
      fhicl::Atom<double> pval{
        Name("momentumInGeV"),
        Comment("Fixed momentum estimate value, to be used when momFromCalo, momFromLength and "
                "momFromMC are all false, or if the estimate is not available.") //momFromMSChi2,
      };
      fhicl::Atom<int> pdgId{
        Name("pdgId"),
        Comment("Default particle id hypothesis in case no valid id is provided either via "
                "PFParticle or in the ParticleId collection.")};
      fhicl::Atom<bool> dirFromMC{Name("dirFromMC"), Comment("Assume track direction from MC.")};
      fhicl::Atom<bool> dirFromVec{Name("dirFromVec"),
                                   Comment("Assume track direction from as the one giving positive "
                                           "dot product with vector specified by dirVec.")};
      fhicl::Sequence<float, 3u> dirVec{Name("dirVec"),
                                        Comment("Fhicl sequence defining the vector used when "
                                                "dirFromVec=true. It must have 3 elements.")};
      fhicl::Atom<bool> alwaysInvertDir{
        Name("alwaysInvertDir"),
        Comment("If true, fit all tracks from end to vertex assuming inverted direction.")};
      fhicl::Atom<bool> produceTrackFitHitInfo{
        Name("produceTrackFitHitInfo"),
        Comment("Option to produce (or not) the detailed TrackFitHitInfo.")};
      fhicl::Atom<bool> produceSpacePoints{
        Name("produceSpacePoints"),
        Comment("Option to produce (or not) the associated SpacePoints.")};
      fhicl::Atom<bool> keepInputTrajectoryPoints{
        Name("keepInputTrajectoryPoints"),
        Comment("Option to keep positions and directions from input trajectory. The fit will "
                "provide only covariance matrices, chi2, ndof, particle Id and absolute momentum. "
                "It may also modify the trajectory point flags. In order to avoid inconsistencies, "
                "it has to be used with the following fitter options all set to false: "
                "sortHitsByPlane, sortOutputHitsMinLength, skipNegProp.")};
    };

    struct Config {
      using Name = fhicl::Name;
      fhicl::Table<KalmanFilterTrajectoryFitter::Inputs> inputs{
        Name("inputs"),
      };
      fhicl::Table<KalmanFilterTrajectoryFitter::Options> options{Name("options")};
      fhicl::Table<TrackStatePropagator::Config> propagator{Name("propagator")};
      fhicl::Table<TrackKalmanFitter::Config> fitter{Name("fitter")};
    };
    using Parameters = art::EDProducer::Table<Config>;

    explicit KalmanFilterTrajectoryFitter(Parameters const& p);

    // Plugins should not be copied or assigned.
    KalmanFilterTrajectoryFitter(KalmanFilterTrajectoryFitter const&) = delete;
    KalmanFilterTrajectoryFitter(KalmanFilterTrajectoryFitter&&) = delete;
    KalmanFilterTrajectoryFitter& operator=(KalmanFilterTrajectoryFitter const&) = delete;
    KalmanFilterTrajectoryFitter& operator=(KalmanFilterTrajectoryFitter&&) = delete;

  private:
    void produce(art::Event& e) override;

    Parameters p_;
    TrackStatePropagator prop;
    trkf::TrackKalmanFitter kalmanFitter;
    trkf::TrackMomentumCalculator tmc{};

    art::InputTag trajectoryInputTag;
    art::InputTag simTrackInputTag;

    bool isTT;

    double setMomValue(const recob::TrackTrajectory* ptraj, const double pMC, const int pId) const;
    int setPId() const;
    bool setDirFlip(const recob::TrackTrajectory* ptraj, TVector3& mcdir) const;

    void restoreInputPoints(const recob::TrackTrajectory& track,
                            const std::vector<art::Ptr<recob::Hit>>& inHits,
                            recob::Track& outTrack,
                            std::vector<art::Ptr<recob::Hit>>& outHits) const;
  };
}

trkf::KalmanFilterTrajectoryFitter::KalmanFilterTrajectoryFitter(
  trkf::KalmanFilterTrajectoryFitter::Parameters const& p)
  : EDProducer{p}
  , p_(p)
  , prop{p_().propagator}
  , kalmanFitter{&prop, p_().fitter}
  , trajectoryInputTag{p_().inputs().inputTrajectoryLabel()}
{
  if (p_().options().pFromMC() || p_().options().dirFromMC())
    simTrackInputTag = art::InputTag{p_().inputs().inputMCLabel()};

  isTT = p_().inputs().isTrackTrajectory();

  produces<std::vector<recob::Track>>();
  produces<art::Assns<recob::Track, recob::Hit>>();
  produces<art::Assns<recob::Track, recob::Hit, recob::TrackHitMeta>>();
  if (isTT) { produces<art::Assns<recob::TrackTrajectory, recob::Track>>(); }
  else {
    produces<art::Assns<recob::Trajectory, recob::Track>>();
  }
  if (p_().options().produceTrackFitHitInfo()) {
    produces<std::vector<std::vector<recob::TrackFitHitInfo>>>();
  }
  if (p_().options().produceSpacePoints()) {
    produces<std::vector<recob::SpacePoint>>();
    produces<art::Assns<recob::Hit, recob::SpacePoint>>();
  }

  //throw expections to avoid possible silent failures due to incompatible configuration options

  unsigned int nDirs = 0;
  if (p_().options().dirFromMC()) nDirs++;
  if (p_().options().dirFromVec()) nDirs++;
  if (p_().options().alwaysInvertDir()) nDirs++;
  if (nDirs > 1) {
    throw cet::exception("KalmanFilterTrajectoryFitter")
      << "Incompatible configuration parameters: only at most one can be set to true among "
         "dirFromMC, dirFromVec, and alwaysInvertDir."
      << "\n";
  }

  unsigned int nPFroms = 0;
  if (p_().options().pFromLength()) nPFroms++;
  if (p_().options().pFromMC()) nPFroms++;
  if (nPFroms > 1) {
    throw cet::exception("KalmanFilterTrajectoryFitter")
      << "Incompatible configuration parameters: only at most one can be set to true among "
         "pFromLength, and pFromMC."
      << "\n"; //pFromMSChi2,
  }

  if (p_().options().keepInputTrajectoryPoints()) {
    if (p_().fitter().sortHitsByPlane() || p_().fitter().sortOutputHitsMinLength() ||
        p_().fitter().skipNegProp()) {
      throw cet::exception("KalmanFilterTrajectoryFitter")
        << "Incompatible configuration parameters: keepInputTrajectoryPoints needs the following "
           "fitter options all set to false: sortHitsByPlane, sortOutputHitsMinLength, skipNegProp."
        << "\n";
    }
  }
}

void
trkf::KalmanFilterTrajectoryFitter::produce(art::Event& e)
{

  auto outputTracks = std::make_unique<std::vector<recob::Track>>();
  auto outputHitsMeta =
    std::make_unique<art::Assns<recob::Track, recob::Hit, recob::TrackHitMeta>>();
  auto outputHits = std::make_unique<art::Assns<recob::Track, recob::Hit>>();
  auto outputHitInfo = std::make_unique<std::vector<std::vector<recob::TrackFitHitInfo>>>();

  //only one will be filled and pushed into the event:
  auto outputTTjTAssn = std::make_unique<art::Assns<recob::TrackTrajectory, recob::Track>>();
  auto outputTjTAssn = std::make_unique<art::Assns<recob::Trajectory, recob::Track>>();

  auto const tid = e.getProductID<std::vector<recob::Track>>();
  auto const tidgetter = e.productGetter(tid);

  auto outputSpacePoints = std::make_unique<std::vector<recob::SpacePoint>>();
  auto outputHitSpacePointAssn = std::make_unique<art::Assns<recob::Hit, recob::SpacePoint>>();
  auto const spid = e.getProductID<std::vector<recob::SpacePoint>>();
  auto const spidgetter = e.productGetter(spid);

  //FIXME, eventually remove this (ok only for single particle MC)
  double pMC = -1.;
  TVector3 mcdir;
  if (p_().options().pFromMC() || p_().options().dirFromMC()) {
    art::ValidHandle<std::vector<sim::MCTrack>> simTracks =
      e.getValidHandle<std::vector<sim::MCTrack>>(simTrackInputTag);
    for (unsigned int iMC = 0; iMC < simTracks->size(); ++iMC) {
      const sim::MCTrack& mctrack = simTracks->at(iMC);
      //fiducial cuts on MC tracks
      if (mctrack.PdgCode() != 13) continue;
      if (mctrack.Process() != "primary") continue;
      pMC = mctrack.Start().Momentum().P() * 0.001;
      mcdir = TVector3(mctrack.Start().Momentum().X() * 0.001 / pMC,
                       mctrack.Start().Momentum().Y() * 0.001 / pMC,
                       mctrack.Start().Momentum().Z() * 0.001 / pMC);
      break;
    }
    //std::cout << "mc momentum value = " << pval << " GeV" << std::endl;
  }

  unsigned int nTrajs = 0;

  art::Handle<std::vector<recob::TrackTrajectory>> inputTrackTrajectoryH;
  art::Handle<std::vector<recob::Trajectory>> inputTrajectoryH;
  const std::vector<recob::TrackTrajectory>* trackTrajectoryVec = nullptr;
  const std::vector<recob::Trajectory>* trajectoryVec = nullptr;
  const art::Assns<recob::TrackTrajectory, recob::Hit>* trackTrajectoryHitsAssn = nullptr;
  const art::Assns<recob::Trajectory, recob::Hit>* trajectoryHitsAssn = nullptr;
  if (isTT) {
    bool ok = e.getByLabel(trajectoryInputTag, inputTrackTrajectoryH);
    if (!ok)
      throw cet::exception("KalmanFilterTrajectoryFitter")
        << "Cannot find recob::TrackTrajectory art::Handle with inputTag " << trajectoryInputTag;
    trackTrajectoryVec = inputTrackTrajectoryH.product();
    trackTrajectoryHitsAssn =
      e.getValidHandle<art::Assns<recob::TrackTrajectory, recob::Hit>>(trajectoryInputTag)
        .product();
    nTrajs = trackTrajectoryVec->size();
  }
  else {
    bool ok = e.getByLabel(trajectoryInputTag, inputTrajectoryH);
    if (!ok)
      throw cet::exception("KalmanFilterTrajectoryFitter")
        << "Cannot find recob::Trajectory art::Handle with inputTag " << trajectoryInputTag;
    trajectoryVec = inputTrajectoryH.product();
    trajectoryHitsAssn =
      e.getValidHandle<art::Assns<recob::Trajectory, recob::Hit>>(trajectoryInputTag).product();
    nTrajs = trajectoryVec->size();
  }

  auto const detProp = art::ServiceHandle<detinfo::DetectorPropertiesService const>()->DataFor(e);

  for (unsigned int iTraj = 0; iTraj < nTrajs; ++iTraj) {

    const recob::TrackTrajectory& inTraj =
      (isTT ? trackTrajectoryVec->at(iTraj) :
              recob::TrackTrajectory(trajectoryVec->at(iTraj),
                                     std::vector<recob::TrajectoryPointFlags>()));
    // this is not computationally optimal, but at least preserves the order
    // unlike FindManyP
    std::vector<art::Ptr<recob::Hit>> inHits;
    if (isTT) {
      for (auto it = trackTrajectoryHitsAssn->begin(); it != trackTrajectoryHitsAssn->end(); ++it) {
        if (it->first.key() == iTraj)
          inHits.push_back(it->second);
        else if (inHits.size() > 0)
          break;
      }
    }
    else {
      for (auto it = trajectoryHitsAssn->begin(); it != trajectoryHitsAssn->end(); ++it) {
        if (it->first.key() == iTraj)
          inHits.push_back(it->second);
        else if (inHits.size() > 0)
          break;
      }
    }
    const int pId = setPId();
    const double mom = setMomValue(&inTraj, pMC, pId);
    const bool flipDir = setDirFlip(&inTraj, mcdir);

    recob::Track outTrack;
    std::vector<art::Ptr<recob::Hit>> outHits;
    trkmkr::OptionalOutputs optionals;
    if (p_().options().produceTrackFitHitInfo()) optionals.initTrackFitInfos();
    bool fitok = kalmanFitter.fitTrack(detProp,
                                       inTraj,
                                       iTraj,
                                       SMatrixSym55(),
                                       SMatrixSym55(),
                                       inHits, // inFlags,
                                       mom,
                                       pId,
                                       flipDir,
                                       outTrack,
                                       outHits,
                                       optionals);
    if (!fitok) continue;

    if (p_().options().keepInputTrajectoryPoints()) {
      restoreInputPoints(inTraj, inHits, outTrack, outHits);
    }

    outputTracks->emplace_back(std::move(outTrack));
    art::Ptr<recob::Track> aptr(tid, outputTracks->size() - 1, tidgetter);
    unsigned int ip = 0;
    for (auto const& trhit : outHits) {
      //the fitter produces collections with 1-1 match between hits and point
      recob::TrackHitMeta metadata(ip, -1);
      outputHitsMeta->addSingle(aptr, trhit, metadata);
      outputHits->addSingle(aptr, trhit);
      if (p_().options().produceSpacePoints() && outputTracks->back().HasValidPoint(ip)) {
        auto& tp = outputTracks->back().Trajectory().LocationAtPoint(ip);
        double fXYZ[3] = {tp.X(), tp.Y(), tp.Z()};
        double fErrXYZ[6] = {0};
        recob::SpacePoint sp(fXYZ, fErrXYZ, -1.);
        outputSpacePoints->emplace_back(std::move(sp));
        art::Ptr<recob::SpacePoint> apsp(spid, outputSpacePoints->size() - 1, spidgetter);
        outputHitSpacePointAssn->addSingle(trhit, apsp);
      }
      ip++;
    }
    outputHitInfo->emplace_back(optionals.trackFitHitInfos());
    if (isTT) {
      outputTTjTAssn->addSingle(art::Ptr<recob::TrackTrajectory>(inputTrackTrajectoryH, iTraj),
                                aptr);
    }
    else {
      outputTjTAssn->addSingle(art::Ptr<recob::Trajectory>(inputTrajectoryH, iTraj), aptr);
    }
  }
  e.put(std::move(outputTracks));
  e.put(std::move(outputHitsMeta));
  e.put(std::move(outputHits));
  if (p_().options().produceTrackFitHitInfo()) { e.put(std::move(outputHitInfo)); }
  if (p_().options().produceSpacePoints()) {
    e.put(std::move(outputSpacePoints));
    e.put(std::move(outputHitSpacePointAssn));
  }
  if (isTT)
    e.put(std::move(outputTTjTAssn));
  else
    e.put(std::move(outputTjTAssn));
}

void
trkf::KalmanFilterTrajectoryFitter::restoreInputPoints(
  const recob::TrackTrajectory& track,
  const std::vector<art::Ptr<recob::Hit>>& inHits,
  recob::Track& outTrack,
  std::vector<art::Ptr<recob::Hit>>& outHits) const
{
  const auto np = outTrack.NumberTrajectoryPoints();
  std::vector<Point_t> positions(np);
  std::vector<Vector_t> momenta(np);
  std::vector<recob::TrajectoryPointFlags> outFlags(np);
  //
  for (unsigned int p = 0; p < np; ++p) {
    auto flag = outTrack.FlagsAtPoint(p);
    auto mom = outTrack.VertexMomentum();
    auto op = flag.fromHit();
    positions[op] = track.LocationAtPoint(op);
    momenta[op] = mom * track.DirectionAtPoint(op);
    auto mask = flag.mask();
    if (mask.isSet(recob::TrajectoryPointFlagTraits::NoPoint))
      mask.unset(recob::TrajectoryPointFlagTraits::NoPoint);
    outFlags[op] = recob::TrajectoryPointFlags(op, mask);
  }
  auto covs = outTrack.Covariances();
  outTrack = recob::Track(
    recob::TrackTrajectory(std::move(positions), std::move(momenta), std::move(outFlags), true),
    outTrack.ParticleId(),
    outTrack.Chi2(),
    outTrack.Ndof(),
    std::move(covs.first),
    std::move(covs.second),
    outTrack.ID());
  //
  outHits.clear();
  for (auto h : inHits)
    outHits.push_back(h);
}

double
trkf::KalmanFilterTrajectoryFitter::setMomValue(const recob::TrackTrajectory* ptraj,
                                                const double pMC,
                                                const int pId) const
{
  double result = p_().options().pval();
  if (p_().options().pFromLength()) { result = tmc.GetTrackMomentum(ptraj->Length(), pId); }
  else if (p_().options().pFromMC() && pMC > 0.) {
    result = pMC;
  }
  return result;
}

int
trkf::KalmanFilterTrajectoryFitter::setPId() const
{
  int result = p_().options().pdgId();
  return result;
}

bool
trkf::KalmanFilterTrajectoryFitter::setDirFlip(const recob::TrackTrajectory* ptraj,
                                               TVector3& mcdir) const
{
  bool result = false;
  if (p_().options().alwaysInvertDir()) { return true; }
  else if (p_().options().dirFromMC()) {
    auto tdir = ptraj->VertexDirection();
    if ((mcdir.X() * tdir.X() + mcdir.Y() * tdir.Y() + mcdir.Z() * tdir.Z()) < 0.) result = true;
  }
  else if (p_().options().dirFromVec()) {
    std::array<float, 3> dir = p_().options().dirVec();
    auto tdir = ptraj->VertexDirection();
    if ((dir[0] * tdir.X() + dir[1] * tdir.Y() + dir[2] * tdir.Z()) < 0.) result = true;
  }
  return result;
}

DEFINE_ART_MODULE(trkf::KalmanFilterTrajectoryFitter)