SpacePointAna_module.cc

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//
// Name: SpacePointAna_module.cc
//
// Purpose: Module SpacePointAna.
//
//
// Configuration parameters.
//
//  HitModuleLabel:        Hit module label.
//  UseClusterHits:        If true, use clustered hits (otherwise all hits).
//  ClusterModuleLabel:    Cluster module label.
//  UseMC:                 Use MC truth information.
//  SpacePointAlgTime:     SpacePointAlg configuration (loose time cuts).
//  SpacePointAlgSep:      SpacePointAlg configuration (loose separation cuts).
//  SpacePointAlgDefault:  SpacePointAlg configuration (default cuts).
//
// Created: 2-Aug-2011  H. Greenlee
//

#include <iostream>
#include <map>
#include <vector>
#include <algorithm>

#include "art/Framework/Core/ModuleMacros.h" 
#include "art/Framework/Core/EDAnalyzer.h"
#include "canvas/Persistency/Common/FindManyP.h"
#include "art/Framework/Principal/Event.h"
#include "art/Framework/Services/Registry/ServiceHandle.h" 
#include "art/Framework/Services/Optional/TFileService.h" 
#include "messagefacility/MessageLogger/MessageLogger.h"

#include "larreco/RecoAlg/SpacePointAlg.h"
#include "larcore/Geometry/Geometry.h"
#include "larcorealg/Geometry/TPCGeo.h"
#include "larcorealg/Geometry/PlaneGeo.h"
#include "lardata/DetectorInfoServices/DetectorPropertiesService.h"
#include "lardata/Utilities/AssociationUtil.h"
#include "lardataobj/RecoBase/Cluster.h"
#include "lardataobj/RecoBase/Hit.h"
#include "lardataobj/RecoBase/SpacePoint.h"
#include "larsim/MCCheater/BackTrackerService.h"
#include "larsim/MCCheater/ParticleInventoryService.h"

#include "TH1F.h"
#include "TH2F.h"


namespace trkf {

  class SpacePointAna : public art::EDAnalyzer
  {
  public:
 
    // Constructors, destructor

    explicit SpacePointAna(fhicl::ParameterSet const& pset);
    virtual ~SpacePointAna();

    // Book histograms.

    void bookHistograms(bool mc);

    // Overrides.

    void analyze(const art::Event& evt);

  private:

    // Fcl Attributes.

    const SpacePointAlg fSptalgTime;    // Algorithm object (increased time cut).
    const SpacePointAlg fSptalgSep;     // Algorithm object (increased sepataion cut).
    const SpacePointAlg fSptalgDefault; // Algorithm object (default cuts).
    std::string fHitModuleLabel;
    bool fUseClusterHits;
    std::string fClusterModuleLabel;
    bool fUseMC;
    double fMinX;    // Minimum x.
    double fMaxX;    // Maximum x.
    double fMinY;    // Minimum y.
    double fMaxY;    // Maximum y.
    double fMinZ;    // Minimum z.
    double fMaxZ;    // Maximum z.

    // Histograms.

    bool fBooked;    // Have histograms been booked yet?
    TH1F* fHDTUE;    // U-drift electrons time difference.
    TH1F* fHDTVE;    // V-drift electrons time difference.
    TH1F* fHDTWE;    // W-drift electrons time difference.
    TH1F* fHDTUPull; // U-drift electrons time pull.
    TH1F* fHDTVPull; // V-drift electrons time pull.
    TH1F* fHDTWPull; // W-drift electrons time pull.
    TH1F* fHDTUV;    // U-V time difference.
    TH1F* fHDTVW;    // V-W time difference.
    TH1F* fHDTWU;    // W-U time difference.
    TH2F* fHDTUVU;   // U-V time difference vs. U.
    TH2F* fHDTUVV;   // U-V time difference vs. V.
    TH2F* fHDTVWV;   // V-W time difference vs. V.
    TH2F* fHDTVWW;   // V-W time difference vs. W.
    TH2F* fHDTWUW;   // W-U time difference vs. W.
    TH2F* fHDTWUU;   // W-U time difference vs. U.
    TH1F* fHS;       // Spatial separation.
    TH1F* fHchisq;   // Space point chisquare.
    TH1F* fHx;       // X position.
    TH1F* fHy;       // Y position.
    TH1F* fHz;       // Z position.
    TH1F* fHAmpU;    // U hit amplitude.
    TH1F* fHAmpV;    // V hit amplitude.
    TH1F* fHAmpW;    // W hit amplitude.
    TH1F* fHAreaU;   // U hit area.
    TH1F* fHAreaV;   // V hit area.
    TH1F* fHAreaW;   // W hit area.
    TH1F* fHSumU;    // U hit sum ADC.
    TH1F* fHSumV;    // V hit sum ADC.
    TH1F* fHSumW;    // W hit sum ADC.
    TH1F* fHMCdx;    // X residual (reco vs. mc truth).
    TH1F* fHMCdy;    // Y residual (reco vs. mc truth).
    TH1F* fHMCdz;    // Z residual (reco vs. mc truth).
    TH1F* fHMCxpull; // X pull (reco vs. mc truth).
    TH1F* fHMCypull; // Y pull (reco vs. mc truth).
    TH1F* fHMCzpull; // Z pull (reco vs. mc truth).

    // Statistics.

    int fNumEvent;
  };

  DEFINE_ART_MODULE(SpacePointAna)

  SpacePointAna::SpacePointAna(const fhicl::ParameterSet& pset)
    //
    // Purpose: Constructor.
    //
    // Arguments: pset - Module parameters.
    //
  : EDAnalyzer(pset)
   , fSptalgTime(pset.get<fhicl::ParameterSet>("SpacePointAlgTime"))
   , fSptalgSep(pset.get<fhicl::ParameterSet>("SpacePointAlgSep"))
   , fSptalgDefault(pset.get<fhicl::ParameterSet>("SpacePointAlgDefault"))
   , fHitModuleLabel(pset.get<std::string>("HitModuleLabel"))
   , fUseClusterHits(pset.get<bool>("UseClusterHits"))
   , fClusterModuleLabel(pset.get<std::string>("ClusterModuleLabel"))
   , fUseMC(pset.get<bool>("UseMC"))
   , fMinX(pset.get<double>("MinX", -1.e10))
   , fMaxX(pset.get<double>("MaxX", 1.e10))
   , fMinY(pset.get<double>("MinY", -1.e10))
   , fMaxY(pset.get<double>("MaxY", 1.e10))
   , fMinZ(pset.get<double>("MinZ", -1.e10))
   , fMaxZ(pset.get<double>("MaxZ", 1.e10))
   , fBooked(false)
   , fHDTUE(0)
   , fHDTVE(0)
   , fHDTWE(0)
   , fHDTUPull(0)
   , fHDTVPull(0)
   , fHDTWPull(0)
   , fHDTUV(0)
   , fHDTVW(0)
   , fHDTWU(0)
   , fHDTUVU(0)
   , fHDTUVV(0)
   , fHDTVWV(0)
   , fHDTVWW(0)
   , fHDTWUW(0)
   , fHDTWUU(0)
   , fHS(0)
   , fHchisq(0)
   , fHx(0)
   , fHy(0)
   , fHz(0)
   , fHAmpU(0)
   , fHAmpV(0)
   , fHAmpW(0)
   , fHAreaU(0)
   , fHAreaV(0)
   , fHAreaW(0)
   , fHSumU(0)
   , fHSumV(0)
   , fHSumW(0)
   , fHMCdx(0)
   , fHMCdy(0)
   , fHMCdz(0)
   , fHMCxpull(0)
   , fHMCypull(0)
   , fHMCzpull(0)
   , fNumEvent(0)
  {

    // Report.

    mf::LogInfo("SpacePointAna") 
      << "SpacePointAna configured with the following parameters:\n"
      << "  HitModuleLabel = " << fHitModuleLabel << "\n"
      << "  UseClusterHits = " << fUseClusterHits << "\n"
      << "  ClusterModuleLabel = " << fClusterModuleLabel << "\n"
      << "  UseMC = " << fUseMC;
  }

  SpacePointAna::~SpacePointAna()
  //
  // Purpose: Destructor.
  //
  {}

  void SpacePointAna::bookHistograms(bool mc)
  //
  // Purpose: Book histograms.
  //
  {
    if(!fBooked) {
      fBooked = true;

      art::ServiceHandle<geo::Geometry> geom;
      art::ServiceHandle<art::TFileService> tfs;
      art::TFileDirectory dir = tfs->mkdir("sptana", "SpacePointAna histograms");

      unsigned int nwiresU=0, nwiresV=0, nwiresW=0;

      // Figure out the number of wires in U, V, and W planes.

      // Loop over cryostats, tpcs, and planes.

      for(unsigned int cstat = 0; cstat < geom->Ncryostats(); ++cstat){

        const geo::CryostatGeo& cryogeom = geom->Cryostat(cstat);
        unsigned int const ntpc = cryogeom.NTPC();

        for(unsigned int tpc = 0; tpc < ntpc; ++tpc) {

          const geo::TPCGeo& tpcgeom = cryogeom.TPC(tpc);
          unsigned int const nplane = tpcgeom.Nplanes();
                
          for(unsigned int plane = 0; plane < nplane; ++plane) {

            const geo::PlaneGeo& pgeom = tpcgeom.Plane(plane);
            unsigned int nwires = pgeom.Nwires();
            geo::View_t view = pgeom.View();
            if(view == geo::kU)
              nwiresU = nwires;
            else if(view == geo::kV)
              nwiresV = nwires;
            else if(view == geo::kZ)
              nwiresW = nwires;
          }
        }
      }
 



      if(mc && fUseMC) {
        fHDTUE = dir.make<TH1F>("MCDTUE", "U-Drift Electrons Time Difference", 100, -5., 5.);
        fHDTVE = dir.make<TH1F>("MCDTVE", "V-Drift Electrons Time Difference", 100, -5., 5.);
        fHDTWE = dir.make<TH1F>("MCDTWE", "W-Drift Electrons Time Difference", 100, -5., 5.);
        fHDTUPull = dir.make<TH1F>("MCDTUPull", "U-Drift Electrons Time Pull", 100, -50., 50.);
        fHDTVPull = dir.make<TH1F>("MCDTVPull", "V-Drift Electrons Time Pull", 100, -50., 50.);
        fHDTWPull = dir.make<TH1F>("MCDTWPull", "W-Drift Electrons Time Pull", 100, -50., 50.);
      }
      if(!fSptalgTime.merge()) {
        fHDTUV = dir.make<TH1F>("DTUV", "U-V time difference", 100, -20., 20.);
        fHDTVW = dir.make<TH1F>("DTVW", "V-W time difference", 100, -20., 20.);
        fHDTWU = dir.make<TH1F>("DTWU", "W-U time difference", 100, -20., 20.);
        fHDTUVU = dir.make<TH2F>("DTUVU", "U-V time difference vs. U",
                                 100, 0., double(nwiresU), 100, -20., 20.);
        fHDTUVV = dir.make<TH2F>("DTUVV", "U-V time difference vs. V",
                                 100, 0., double(nwiresV), 100, -20., 20.);
        fHDTVWV = dir.make<TH2F>("DTVWV", "V-W time difference vs. V",
                                 100, 0., double(nwiresV), 100, -20., 20.);
        fHDTVWW = dir.make<TH2F>("DTVWW", "V-W time difference vs. W",
                                 100, 0., double(nwiresW), 100, -20., 20.);
        fHDTWUW = dir.make<TH2F>("DTWUW", "W-U time difference vs. W",
                                 100, 0., double(nwiresW), 100, -20., 20.);
        fHDTWUU = dir.make<TH2F>("DTWUU", "W-U time difference vs. U",
                                 100, 0., double(nwiresU), 100, -20., 20.);
        fHS = dir.make<TH1F>("DS", "Spatial Separation", 100, -2., 2.);
      }
      fHchisq = dir.make<TH1F>("chisq", "Chisquare", 100, 0., 20.);

      fHx = dir.make<TH1F>("xpos", "X Position",
                           100, 0., 2.*geom->DetHalfWidth());
      fHy = dir.make<TH1F>("ypos", "Y Position",
                           100, -geom->DetHalfHeight(), geom->DetHalfHeight());
      fHz = dir.make<TH1F>("zpos", "Z Position",
                           100, 0., geom->DetLength());
      fHAmpU = dir.make<TH1F>("ampU", "U Hit Amplitude", 50, 0., 50.);
      fHAmpV = dir.make<TH1F>("ampV", "V Hit Amplitude", 50, 0., 50.);
      fHAmpW = dir.make<TH1F>("ampW", "W Hit Amplitude", 50, 0., 50.);
      fHAreaU = dir.make<TH1F>("areaU", "U Hit Area", 100, 0., 500.);
      fHAreaV = dir.make<TH1F>("areaV", "V Hit Area", 100, 0., 500.);
      fHAreaW = dir.make<TH1F>("areaW", "W Hit Area", 100, 0., 500.);
      fHSumU = dir.make<TH1F>("sumU", "U Hit Sum ADC", 100, 0., 500.);
      fHSumV = dir.make<TH1F>("sumV", "V Hit Sum ADC", 100, 0., 500.);
      fHSumW = dir.make<TH1F>("sumW", "W Hit Sum ADC", 100, 0., 500.);
      if(mc && fUseMC) {
        fHMCdx = dir.make<TH1F>("MCdx", "X MC Residual", 100, -1., 1.);
        fHMCdy = dir.make<TH1F>("MCdy", "Y MC Residual", 100, -1., 1.);
        fHMCdz = dir.make<TH1F>("MCdz", "Z MC Residual", 100, -1., 1.);
        fHMCxpull = dir.make<TH1F>("MCxpull", "X MC Pull", 100, -50., 50.);
        fHMCypull = dir.make<TH1F>("MCypull", "Y MC Pull", 100, -50., 50.);
        fHMCzpull = dir.make<TH1F>("MCzpull", "Z MC Pull", 100, -50., 50.);
      }
    }
  }

  void SpacePointAna::analyze(const art::Event& evt)
  //
  // Purpose: Analyze method.
  //
  // Arguments: event - Art event.
  //
  {
    ++fNumEvent;

    // Make sure histograms are booked.

    bool mc = !evt.isRealData();
    bookHistograms(mc);

    // Get Services.

    art::ServiceHandle<geo::Geometry> geom;
    const detinfo::DetectorProperties* detprop = lar::providerFrom<detinfo::DetectorPropertiesService>();

    // Get Hits.

    art::PtrVector<recob::Hit> hits;

    if(fUseClusterHits) {

      // Get clusters.

      art::Handle< std::vector<recob::Cluster> > clusterh;
      evt.getByLabel(fClusterModuleLabel, clusterh);

      // Get hits from all clusters.
      art::FindManyP<recob::Hit> fm(clusterh, evt, fClusterModuleLabel);

      if(clusterh.isValid()) {
        int nclus = clusterh->size();

        for(int i = 0; i < nclus; ++i) {
          art::Ptr<recob::Cluster> pclus(clusterh, i);
          std::vector< art::Ptr<recob::Hit> > clushits = fm.at(i);
          int nhits = clushits.size();
          hits.reserve(hits.size() + nhits);

          for(std::vector< art::Ptr<recob::Hit> >::const_iterator ihit = clushits.begin(); ihit != clushits.end(); ++ihit) {
            hits.push_back(*ihit);
          }
        }
      }
    }
    else {

      // Get unclustered hits.

      art::Handle< std::vector<recob::Hit> > hith;
      evt.getByLabel(fHitModuleLabel, hith);
      if(hith.isValid()) {
        int nhits = hith->size();
        hits.reserve(nhits);

        for(int i = 0; i < nhits; ++i)
          hits.push_back(art::Ptr<recob::Hit>(hith, i));
      }
    }

    // Fill histograms that don't depend on space points.

    if(mc && fUseMC) {

      art::ServiceHandle<cheat::BackTrackerService> bt_serv;

      // Loop over hits and fill hit-electron time difference histogram.

      for(art::PtrVector<recob::Hit>::const_iterator ihit = hits.begin();
          ihit != hits.end(); ++ihit) {
        const recob::Hit& hit = **ihit;

        //unsigned int channel = hit.Channel();
        //geo::View_t geo_view = geom->View(channel);
        //geo::View_t hit_view = hit.View();
        //assert(geo_view == hit_view);
        double tpeak = hit.PeakTime();
        double terr = hit.SigmaPeakTime();

        //assert(channel == hit.Channel());

        // Loop over electrons associated with this hit/channel and fill
        // hit-electron time difference histograms.

        // loop over the map of TDC to sim::IDE to get the TDC for each energy dep
        // Find the average time in ticks for this hit.

        //double sumw = 0.;
        //double sumt = 0.;

        //const std::map<unsigned short, std::vector<sim::IDE> > &idemap = simchan.TDCIDEMap();
        //std::map<unsigned short, std::vector<sim::IDE> >::const_iterator mitr = idemap.begin();
        //for(mitr = idemap.begin(); mitr != idemap.end(); mitr++) {
        //  double tdc = double((*mitr).first);
        //  if(tdc >= tstart && tdc <= tend) {
        //    const std::vector<sim::IDE>& idevec = (*mitr).second;
        //    for(std::vector<sim::IDE>::const_iterator iide=idevec.begin();
        //      iide != idevec.end(); ++iide) {
        //      const sim::IDE& ide = *iide;
        //      double w = ide.numElectrons;
        //      sumw += w;
        //      sumt += w*tdc;
        //    }
        //  }
        //}
        //double tav = 0.;
        //if(sumw != 0.)
        //  tav = sumt / sumw;

        bool tav_ok = true;
        double tav = 0.;
        try {
          std::vector<double> hitxyz = bt_serv->HitToXYZ(*ihit);
          tav = detprop->ConvertXToTicks(hitxyz[0], (*ihit)->WireID().Plane, (*ihit)->WireID().TPC, (*ihit)->WireID().Cryostat);
        }
        catch(cet::exception& x) {
          tav_ok = false;
        }
        if(tav_ok) {
          if((*ihit)->View() == geo::kU) {
            fHDTUE->Fill(tpeak - tav);
            fHDTUPull->Fill((tpeak - tav) / terr);
          }
          else if((*ihit)->View() == geo::kV) {
            fHDTVE->Fill(tpeak - tav);
            fHDTVPull->Fill((tpeak - tav) / terr);
          }
          else if((*ihit)->View() == geo::kZ) {
            fHDTWE->Fill(tpeak - tav);
            fHDTWPull->Fill((tpeak - tav) / terr);
          }
          else
            throw cet::exception("SpacePointAna") << "Bad view = " << (*ihit)->View() << "\n";
        }
      }
    }
    
    std::vector<recob::SpacePoint> spts1;  // For time histograms.
    std::vector<recob::SpacePoint> spts2;  // For separation histogram.
    std::vector<recob::SpacePoint> spts3;  // Default cuts.

    // If nonzero time cut is specified, make space points using that
    // time cut (for time histograms).

    if(!fSptalgTime.merge()) {
      if(mc && fUseMC)
        fSptalgTime.makeMCTruthSpacePoints(hits, spts1);
      else
        fSptalgTime.makeSpacePoints(hits, spts1);

      // Report number of space points.

      LOG_DEBUG("SpacePointAna") << "Found " << spts1.size() 
                                    << " space points using special time cut.";
    }

    // If nonzero separation cut is specified, make space points using that 
    // separation cut (for separation histogram).

    if(!fSptalgSep.merge()) {
      if(mc && fUseMC)
        fSptalgSep.makeMCTruthSpacePoints(hits, spts2);
      else
        fSptalgSep.makeSpacePoints(hits, spts2);

      // Report number of space points.

      LOG_DEBUG("SpacePointAna") << "Found " << spts2.size() 
                                    << " space points using special seperation cut.";
    }

    // Make space points using default cuts.

    if(mc && fUseMC)
      fSptalgDefault.makeMCTruthSpacePoints(hits, spts3);
    else
      fSptalgDefault.makeSpacePoints(hits, spts3);

    // Report number of space points.

    LOG_DEBUG("SpacePointAna") << "Found " << spts3.size() 
                                  << " space points using default cuts.";

    if(!fSptalgTime.merge()) {

      // Loop over space points and fill time histograms.

      for(std::vector<recob::SpacePoint>::const_iterator i = spts1.begin(); 
          i != spts1.end(); ++i) {
        const recob::SpacePoint& spt = *i;
        if(spt.XYZ()[0] < fMinX || spt.XYZ()[0] > fMaxX ||
           spt.XYZ()[1] < fMinY || spt.XYZ()[1] > fMaxY ||
           spt.XYZ()[2] < fMinZ || spt.XYZ()[2] > fMaxZ)
          continue;

        // Get hits associated with this SpacePoint.

        const art::PtrVector<recob::Hit>& spthits = fSptalgTime.getAssociatedHits(spt);

        // Make a double loop over hits and fill hit time difference histograms.

        for(art::PtrVector<recob::Hit>::const_iterator ihit = spthits.begin();
            ihit != spthits.end(); ++ihit) {
          const recob::Hit& hit1 = **ihit;

          geo::WireID hit1WireID = hit1.WireID();
          unsigned int tpc1, plane1, wire1;
          tpc1 = hit1WireID.TPC;
          plane1 = hit1WireID.Plane;
          wire1 = hit1WireID.Wire;
                
          geo::View_t view1 = hit1.View();
          double t1 = fSptalgTime.correctedTime(hit1);

          for(art::PtrVector<recob::Hit>::const_iterator jhit = spthits.begin();
              jhit != spthits.end(); ++jhit) {
            const recob::Hit& hit2 = **jhit;

            geo::WireID hit2WireID = hit2.WireID();
            unsigned int tpc2, plane2, wire2;
            tpc2 = hit2WireID.TPC;
            plane2 = hit2WireID.Plane;
            wire2 = hit2WireID.Wire;

            // Require same tpc, different view.

            if(tpc1 == tpc2 && plane1 != plane2) {

              geo::View_t view2 = hit2.View();
              double t2 = fSptalgTime.correctedTime(hit2);

              if(view1 == geo::kU) {
                if(view2 == geo::kV) {
                  fHDTUV->Fill(t1-t2);
                  fHDTUVU->Fill(double(wire1), t1-t2);
                  fHDTUVV->Fill(double(wire2), t1-t2);
                }
                if(view2 == geo::kZ) {
                  fHDTWU->Fill(t2-t1);
                  fHDTWUW->Fill(double(wire2), t2-t1);
                  fHDTWUU->Fill(double(wire1), t2-t1);
                }
              }
              if(view1 == geo::kV) {
                if(view2 == geo::kZ) {
                  fHDTVW->Fill(t1-t2);
                  fHDTVWV->Fill(double(wire1), t1-t2);
                  fHDTVWW->Fill(double(wire2), t1-t2);
                }
                if(view2 == geo::kU) {
                  fHDTUV->Fill(t2-t1);
                  fHDTUVU->Fill(double(wire2), t2-t1);
                  fHDTUVV->Fill(double(wire1), t2-t1);
                }
              }
              if(view1 == geo::kZ) {
                if(view2 == geo::kU) {
                  fHDTWU->Fill(t1-t2);
                  fHDTWUW->Fill(double(wire1), t1-t2);
                  fHDTWUU->Fill(double(wire2), t1-t2);
                }
                if(view2 == geo::kV) {
                  fHDTVW->Fill(t2-t1);
                  fHDTVWV->Fill(double(wire2), t2-t1);
                  fHDTVWW->Fill(double(wire1), t2-t1);
                }
              }
            }
          }
        }
      }

      // Loop over space points and fill seperation histograms.

      for(std::vector<recob::SpacePoint>::const_iterator i = spts2.begin(); 
          i != spts2.end(); ++i) {
        const recob::SpacePoint& spt = *i;
        if(spt.XYZ()[0] < fMinX || spt.XYZ()[0] > fMaxX ||
           spt.XYZ()[1] < fMinY || spt.XYZ()[1] > fMaxY ||
           spt.XYZ()[2] < fMinZ || spt.XYZ()[2] > fMaxZ)
          continue;

        // Get hits associated with this SpacePoint.

        const art::PtrVector<recob::Hit>& spthits = fSptalgSep.getAssociatedHits(spt);

        // Fill separation histogram.

        double sep = fSptalgSep.separation(spthits);
        fHS->Fill(sep);
      }
    }

    // Loop over default space points and fill histograms.

    for(std::vector<recob::SpacePoint>::const_iterator i = spts3.begin();
        i != spts3.end(); ++i) {
      const recob::SpacePoint& spt = *i;
      if(spt.XYZ()[0] < fMinX || spt.XYZ()[0] > fMaxX ||
         spt.XYZ()[1] < fMinY || spt.XYZ()[1] > fMaxY ||
         spt.XYZ()[2] < fMinZ || spt.XYZ()[2] > fMaxZ)
        continue;

      fHchisq->Fill(spt.Chisq());
      fHx->Fill(spt.XYZ()[0]);
      fHy->Fill(spt.XYZ()[1]);
      fHz->Fill(spt.XYZ()[2]);

      // Get hits associated with this SpacePoint.

      std::vector<art::Ptr<recob::Hit> > spthits;
      const art::PtrVector<recob::Hit>& av_spthits = fSptalgDefault.getAssociatedHits(spt);
      for( auto const& ptr : av_spthits ){ spthits.push_back(ptr);}

      // Fill single hit histograms.

      for(art::PtrVector<recob::Hit>::const_iterator ihit = spthits.begin();
          ihit != spthits.end(); ++ihit) {
        const recob::Hit& hit = **ihit;

        geo::View_t view = hit.View();

        if(view == geo::kU) {
          fHAmpU->Fill(hit.PeakAmplitude());
          fHAreaU->Fill(hit.Integral());
          fHSumU->Fill(hit.SummedADC());
        }
        if(view == geo::kV) {
          fHAmpV->Fill(hit.PeakAmplitude());
          fHAreaV->Fill(hit.Integral());
          fHSumV->Fill(hit.SummedADC());
        }
        if(view == geo::kZ) {
          fHAmpW->Fill(hit.PeakAmplitude());
          fHAreaW->Fill(hit.Integral());
          fHSumW->Fill(hit.SummedADC());
        }
      }

      if(mc && fUseMC) {

        art::ServiceHandle<cheat::BackTrackerService> bt_serv;

        try {
          std::vector<double> mcxyz = bt_serv->SpacePointHitsToWeightedXYZ(spthits);
          fHMCdx->Fill(spt.XYZ()[0] - mcxyz[0]);
          fHMCdy->Fill(spt.XYZ()[1] - mcxyz[1]);
          fHMCdz->Fill(spt.XYZ()[2] - mcxyz[2]);
          if(spt.ErrXYZ()[0] > 0.)
            fHMCxpull->Fill((spt.XYZ()[0] - mcxyz[0]) / std::sqrt(spt.ErrXYZ()[0]));
          if(spt.ErrXYZ()[2] > 0.)
            fHMCypull->Fill((spt.XYZ()[1] - mcxyz[1]) / std::sqrt(spt.ErrXYZ()[2]));
          if(spt.ErrXYZ()[5] > 0.)
            fHMCzpull->Fill((spt.XYZ()[2] - mcxyz[2]) / std::sqrt(spt.ErrXYZ()[5]));
        }
        catch(cet::exception& x) {}
      }
    }
  }
}