Shower2DLinearRegressionTrackHitFinder_tool.cc

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//############################################################################
//### Name:        Shower2DLinearRegressionTrackHitFinder                  ###
//### Author:      Dominic Barker (dominic.barker@sheffield.ac.uk)         ###
//### Date:        13.05.19                                                ###
//### Description: Tool for finding the initial shower track using a rms   ###
//###              based method to define when the shower starts to        ###
//###              shower. This methd is derived from the EMShower_module  ###
//############################################################################

//Framework Includes
#include "art/Utilities/ToolMacros.h"

//LArSoft Includes
#include "lardata/DetectorInfoServices/DetectorClocksService.h"
#include "lardata/DetectorInfoServices/DetectorPropertiesService.h"
#include "lardataobj/RecoBase/Cluster.h"
#include "lardataobj/RecoBase/Hit.h"
#include "lardataobj/RecoBase/PFParticle.h"
#include "lardataobj/RecoBase/SpacePoint.h"
#include "larpandora/LArPandoraEventBuilding/LArPandoraShower/Tools/IShowerTool.h"

namespace ShowerRecoTools {

  class Shower2DLinearRegressionTrackHitFinder : IShowerTool {
  public:
    Shower2DLinearRegressionTrackHitFinder(const fhicl::ParameterSet& pset);

    //Calculate the 2D initial track hits
    int CalculateElement(const art::Ptr<recob::PFParticle>& pfparticle,
                         art::Event& Event,
                         reco::shower::ShowerElementHolder& ShowerEleHolder) override;

  private:
    //Function to find the
    std::vector<art::Ptr<recob::Hit>> FindInitialTrackHits(
      const detinfo::DetectorPropertiesData& detProp,
      std::vector<art::Ptr<recob::Hit>>& hits);

    //Function to perform a weighted regression fit.
    Int_t WeightedFit(const Int_t n,
                      const Double_t* x,
                      const Double_t* y,
                      const Double_t* w,
                      Double_t* parm);

    //fcl parameters
    unsigned int fNfitpass; //Number of time to fit the straight
    //line the hits.
    std::vector<unsigned int> fNfithits; //Max number of hits to fit to.
    std::vector<double> fToler;          //Tolerance or each interaction.
    //Defined as the perpendicualar
    //distance from the best fit line.
    bool fApplyChargeWeight; //Apply charge weighting to the fit.
    art::InputTag fPFParticleLabel;
    int fVerbose;
    art::InputTag fHitLabel;
    std::string fShowerStartPositionInputLabel;
    std::string fShowerDirectionInputLabel;
    std::string fInitialTrackHitsOutputLabel;
    std::string fInitialTrackSpacePointsOutputLabel;
  };

  Shower2DLinearRegressionTrackHitFinder::Shower2DLinearRegressionTrackHitFinder(
    const fhicl::ParameterSet& pset)
    : IShowerTool(pset.get<fhicl::ParameterSet>("BaseTools"))
    , fNfitpass(pset.get<unsigned int>("Nfitpass"))
    , fNfithits(pset.get<std::vector<unsigned int>>("Nfithits"))
    , fToler(pset.get<std::vector<double>>("Toler"))
    , fApplyChargeWeight(pset.get<bool>("ApplyChargeWeight"))
    , fPFParticleLabel(pset.get<art::InputTag>("PFParticleLabel"))
    , fVerbose(pset.get<int>("Verbose"))
    , fHitLabel(pset.get<art::InputTag>("HitsModuleLabel"))
    , fShowerStartPositionInputLabel(pset.get<std::string>("ShowerStartPositionInputLabel"))
    , fShowerDirectionInputLabel(pset.get<std::string>("ShowerDirectionInputLabel"))
    , fInitialTrackHitsOutputLabel(pset.get<std::string>("InitialTrackHitsOutputLabel"))
    , fInitialTrackSpacePointsOutputLabel(
        pset.get<std::string>("InitialTrackSpacePointsOutputLabel"))
  {
    if (fNfitpass != fNfithits.size() || fNfitpass != fToler.size()) {
      throw art::Exception(art::errors::Configuration)
        << "Shower2DLinearRegressionTrackHitFinderEMShower: fNfithits and fToler need to have size "
           "fNfitpass";
    }
  }

  int Shower2DLinearRegressionTrackHitFinder::CalculateElement(
    const art::Ptr<recob::PFParticle>& pfparticle,
    art::Event& Event,
    reco::shower::ShowerElementHolder& ShowerEleHolder)
  {

    //This is all based on the shower vertex being known. If it is not lets not do the track
    if (!ShowerEleHolder.CheckElement(fShowerStartPositionInputLabel)) {
      if (fVerbose)
        mf::LogError("Shower2DLinearRegressionTrackHitFinder")
          << "Start position not set, returning " << std::endl;
      return 1;
    }
    if (!ShowerEleHolder.CheckElement(fShowerDirectionInputLabel)) {
      if (fVerbose)
        mf::LogError("Shower2DLinearRegressionTrackHitFinder")
          << "Direction not set, returning " << std::endl;
      return 1;
    }

    geo::Point_t ShowerStartPosition{-999, -999, -999};
    ShowerEleHolder.GetElement(fShowerStartPositionInputLabel, ShowerStartPosition);

    geo::Vector_t ShowerDirection = {-999, -999, -999};
    ShowerEleHolder.GetElement(fShowerDirectionInputLabel, ShowerDirection);

    // Get the assocated pfParicle vertex PFParticles
    auto const pfpHandle = Event.getValidHandle<std::vector<recob::PFParticle>>(fPFParticleLabel);

    //Get the clusters
    auto const clusHandle = Event.getValidHandle<std::vector<recob::Cluster>>(fPFParticleLabel);

    const art::FindManyP<recob::Cluster>& fmc =
      ShowerEleHolder.GetFindManyP<recob::Cluster>(pfpHandle, Event, fPFParticleLabel);
    std::vector<art::Ptr<recob::Cluster>> clusters = fmc.at(pfparticle.key());

    if (clusters.size() < 2) {
      if (fVerbose)
        mf::LogError("Shower2DLinearRegressionTrackHitFinder")
          << "Not enough clusters: " << clusters.size() << std::endl;
      return 1;
    }

    //Get the hit association
    const art::FindManyP<recob::Hit>& fmhc =
      ShowerEleHolder.GetFindManyP<recob::Hit>(clusHandle, Event, fPFParticleLabel);
    std::map<geo::PlaneID, std::vector<art::Ptr<recob::Hit>>> plane_clusters;
    //Loop over the clusters in the plane and get the hits
    for (auto const& cluster : clusters) {

      //Get the hits
      std::vector<art::Ptr<recob::Hit>> hits = fmhc.at(cluster.key());

      for (auto hit : hits) {
        geo::WireID wire = hit->WireID();
        geo::PlaneID plane = wire.asPlaneID();
        plane_clusters[plane].push_back(hit);
      }

      // Was having issues with clusters having hits in multiple planes breaking PMA
      // So switched to the method above. May want to switch back when using PandoraTrack
      //plane_clusters[plane].insert(plane_clusters[plane].end(),hits.begin(),hits.end());
    }

    auto const clockData =
      art::ServiceHandle<detinfo::DetectorClocksService const>()->DataFor(Event);
    auto const detProp =
      art::ServiceHandle<detinfo::DetectorPropertiesService const>()->DataFor(Event, clockData);

    std::vector<art::Ptr<recob::Hit>> InitialTrackHits;
    //Loop over the clusters and order the hits and get the initial track hits in that plane
    for (auto const& cluster : plane_clusters) {

      //Get the hits
      std::vector<art::Ptr<recob::Hit>> hits = cluster.second;

      //Order the hits
      IShowerTool::GetLArPandoraShowerAlg().OrderShowerHits(
        detProp, hits, ShowerStartPosition, ShowerDirection);

      //Find the initial track hits
      std::vector<art::Ptr<recob::Hit>> trackhits = FindInitialTrackHits(detProp, hits);

      InitialTrackHits.insert(InitialTrackHits.end(), trackhits.begin(), trackhits.end());
    }

    //Holders for the initial track values.
    ShowerEleHolder.SetElement(InitialTrackHits, fInitialTrackHitsOutputLabel);

    //Get the associated spacepoints
    //Get the hits
    auto const hitHandle = Event.getValidHandle<std::vector<recob::Hit>>(fHitLabel);

    //get the sp<->hit association
    const art::FindManyP<recob::SpacePoint>& fmsp =
      ShowerEleHolder.GetFindManyP<recob::SpacePoint>(hitHandle, Event, fPFParticleLabel);

    //Get the spacepoints associated to the track hit
    std::vector<art::Ptr<recob::SpacePoint>> intitaltrack_sp;
    for (auto const& hit : InitialTrackHits) {
      std::vector<art::Ptr<recob::SpacePoint>> sps = fmsp.at(hit.key());
      for (auto const sp : sps) {
        intitaltrack_sp.push_back(sp);
      }
    }
    ShowerEleHolder.SetElement(intitaltrack_sp, fInitialTrackSpacePointsOutputLabel);
    return 0;
  }

  //Function to calculate the what are the initial tracks hits. Adapted from EMShower FindInitialTrackHits
  std::vector<art::Ptr<recob::Hit>> Shower2DLinearRegressionTrackHitFinder::FindInitialTrackHits(
    const detinfo::DetectorPropertiesData& detProp,
    std::vector<art::Ptr<recob::Hit>>& hits)
  {

    std::vector<art::Ptr<recob::Hit>> trackHits;

    double parm[2];
    int fitok = 0;
    std::vector<double> wfit;
    std::vector<double> tfit;
    std::vector<double> cfit;

    for (size_t i = 0; i < fNfitpass; ++i) {

      // Fit a straight line through hits
      unsigned int nhits = 0;
      for (auto& hit : hits) {

        //Not sure I am a fan of doing things in wire tick space. What if id doesn't not iterate properly or the
        //two planes in each TPC are not symmetric.
        TVector2 coord = IShowerTool::GetLArPandoraShowerAlg().HitCoordinates(detProp, hit);

        if (i == 0 ||
            (std::abs((coord.Y() - (parm[0] + coord.X() * parm[1])) *
                      std::cos(std::atan(parm[1]))) < fToler[i - 1]) ||
            fitok == 1) {
          ++nhits;
          if (nhits == fNfithits[i] + 1) break;
          wfit.push_back(coord.X());
          tfit.push_back(coord.Y());

          if (fApplyChargeWeight) { cfit.push_back(hit->Integral()); }
          else {
            cfit.push_back(1.);
          };
          if (i == fNfitpass - 1) { trackHits.push_back(hit); }
        }
      }

      if (i < fNfitpass - 1 && wfit.size()) {
        fitok = WeightedFit(wfit.size(), &wfit[0], &tfit[0], &cfit[0], &parm[0]);
      }

      wfit.clear();
      tfit.clear();
      cfit.clear();
    }
    return trackHits;
  }

  //Stolen from EMShowerAlg, a linear regression fitting function
  Int_t Shower2DLinearRegressionTrackHitFinder::WeightedFit(const Int_t n,
                                                            const Double_t* x,
                                                            const Double_t* y,
                                                            const Double_t* w,
                                                            Double_t* parm)
  {

    Double_t sumx = 0.;
    Double_t sumx2 = 0.;
    Double_t sumy = 0.;
    Double_t sumxy = 0.;
    Double_t sumw = 0.;
    Double_t eparm[2];

    parm[0] = 0.;
    parm[1] = 0.;
    eparm[0] = 0.;
    eparm[1] = 0.;

    for (Int_t i = 0; i < n; i++) {
      sumx += x[i] * w[i];
      sumx2 += x[i] * x[i] * w[i];
      sumy += y[i] * w[i];
      sumxy += x[i] * y[i] * w[i];
      sumw += w[i];
    }

    if (sumx2 * sumw - sumx * sumx == 0.) return 1;
    if (sumx2 - sumx * sumx / sumw == 0.) return 1;

    parm[0] = (sumy * sumx2 - sumx * sumxy) / (sumx2 * sumw - sumx * sumx);
    parm[1] = (sumxy - sumx * sumy / sumw) / (sumx2 - sumx * sumx / sumw);

    eparm[0] = sumx2 * (sumx2 * sumw - sumx * sumx);
    eparm[1] = (sumx2 - sumx * sumx / sumw);

    if (eparm[0] < 0. || eparm[1] < 0.) return 1;

    eparm[0] = sqrt(eparm[0]) / (sumx2 * sumw - sumx * sumx);
    eparm[1] = sqrt(eparm[1]) / (sumx2 - sumx * sumx / sumw);

    return 0;
  }
}

DEFINE_ART_CLASS_TOOL(ShowerRecoTools::Shower2DLinearRegressionTrackHitFinder)