EgammaPCAHelper.cc

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#include "RecoEgamma/EgammaTools/interface/EgammaPCAHelper.h"

#include "DataFormats/HGCRecHit/interface/HGCRecHit.h"
#include "DataFormats/Math/interface/deltaPhi.h"
#include "DataFormats/ForwardDetId/interface/HGCalDetId.h"
#include "DataFormats/HcalDetId/interface/HcalDetId.h"

// To retrieve HGCalImagingAlgo::maxlayer
// Also available as HGCal3DClustering::lastLayerBH and HGCalDepthPreClusterer::lastLayerBH
#include "RecoLocalCalo/HGCalRecAlgos/interface/HGCalImagingAlgo.h"

#include <algorithm>
#include <iostream>

using namespace hgcal;

EGammaPCAHelper::EGammaPCAHelper():
  // Thickness correction to dEdx weights
  // (100um, 200um, 300um silicon)
  // See RecoLocalCalo.HGCalRecProducers.HGCalRecHit_cfi
  invThicknessCorrection_({1. / 1.132, 1. / 1.092, 1. / 1.084}),
  pca_(new TPrincipal(3, "D")) {
    hitMapOrigin_ = 0;
    hitMap_ = new std::map<DetId, const HGCRecHit *>();
    debug_ = false;
}

EGammaPCAHelper::~EGammaPCAHelper() {
    if (hitMapOrigin_ == 2) delete hitMap_;
}

void EGammaPCAHelper::setHitMap( std::map<DetId,const HGCRecHit *> * hitMap) {
    hitMapOrigin_ = 1;
    hitMap_ = hitMap ;
    pcaIteration_ = 0;
}

void EGammaPCAHelper::setRecHitTools(const hgcal::RecHitTools * recHitTools ) {
    recHitTools_ = recHitTools;
}

void EGammaPCAHelper::fillHitMap(const HGCRecHitCollection & rechitsEE,
                                 const HGCRecHitCollection & rechitsFH,
                                 const HGCRecHitCollection & rechitsBH) {
    hitMap_->clear();
    for (const auto& hit : rechitsEE) {
        hitMap_->emplace_hint(hitMap_->end(), hit.detid(), &hit);
    }

    for (const auto& hit : rechitsFH) {
        hitMap_->emplace_hint(hitMap_->end(), hit.detid(), &hit);
    }

    for (const auto& hit : rechitsBH) {
        hitMap_->emplace_hint(hitMap_->end(), hit.detid(), &hit);
    }

    pcaIteration_ = 0;
    hitMapOrigin_ = 2;
}

void EGammaPCAHelper::storeRecHits(const reco::HGCalMultiCluster &cluster ){
    theCluster_ = &cluster;
    std::vector<std::pair<DetId, float>> result;
    for (reco::HGCalMultiCluster::component_iterator it = cluster.begin(); it != cluster.end();
    it++) {
        const std::vector<std::pair<DetId, float>> &hf = (*it)->hitsAndFractions();
        result.insert(result.end(),hf.begin(),hf.end());
    }
    storeRecHits(result);
}

void EGammaPCAHelper::storeRecHits(const reco::CaloCluster & cluster) {
    theCluster_ = &cluster;
    storeRecHits(cluster.hitsAndFractions());
}

void EGammaPCAHelper::storeRecHits(const std::vector<std::pair<DetId, float>> &hf) {
    std::vector<double> pcavars;
    pcavars.resize(3,0.);
    theSpots_.clear();
    pcaIteration_ = 0;

    sigu_ = 0.;
    sigv_ = 0.;
    sigp_ = 0.;
    sige_ = 0.;

    unsigned hfsize = hf.size();
    if (debug_)
        std::cout << "The seed cluster constains " << hfsize << " hits " << std::endl;

    if (hfsize == 0) return;


    for (unsigned int j = 0; j < hfsize; j++) {
        unsigned int layer = recHitTools_->getLayerWithOffset(hf[j].first);

        const DetId rh_detid = hf[j].first;
        std::map<DetId,const HGCRecHit *>::const_iterator itcheck= hitMap_->find(rh_detid);
        if (itcheck == hitMap_->end()) {
            edm::LogWarning("EgammaPCAHelper") << " Big problem, unable to find a hit " << rh_detid.rawId() << " " << rh_detid.det() << " " << HGCalDetId(rh_detid) << std::endl;
            continue;
        }
        if (debug_) {
            std::cout << "DetId " << rh_detid.rawId() << " " << layer << " " <<  itcheck->second->energy() <<std::endl;
            std::cout << " Hit " << itcheck->second << " " << itcheck->second->energy() << std::endl;
        }
        float fraction = hf[j].second;

        double thickness = (DetId::Forward == DetId(rh_detid).det()) ? recHitTools_->getSiThickness(rh_detid) : -1;
        double mip = dEdXWeights_[layer] * 0.001;  // convert in GeV
        if (thickness > 99. && thickness < 101)
            mip *= invThicknessCorrection_[0];
        else if (thickness > 199 && thickness < 201)
            mip *= invThicknessCorrection_[1];
        else if (thickness > 299 && thickness < 301)
            mip *= invThicknessCorrection_[2];

        pcavars[0] = recHitTools_->getPosition(rh_detid).x();
        pcavars[1] = recHitTools_->getPosition(rh_detid).y();
        pcavars[2] = recHitTools_->getPosition(rh_detid).z();
        if (pcavars[2] == 0.)
            edm::LogWarning("EgammaPCAHelper") << " Problem, hit with z =0 ";
        else  {
            Spot mySpot(rh_detid,itcheck->second->energy(),pcavars,layer,fraction,mip);
            theSpots_.push_back(mySpot);
        }
    }
    if (debug_) {
        std::cout << " Stored " << theSpots_.size() << " hits " << std::endl;
    }
}

void EGammaPCAHelper::computePCA(float radius , bool withHalo) {
    // very important - to reset
    pca_.reset(new TPrincipal(3, "D"));
    bool initialCalculation = radius < 0;
    if (debug_)
        std::cout << " Initial calculation " << initialCalculation << std::endl;
    if (initialCalculation && withHalo) {
        edm::LogWarning("EGammaPCAHelper") << "Warning - in the first iteration, the halo hits are excluded " << std::endl;
        withHalo=false;
    }

    float radius2 = radius*radius;
    if (! initialCalculation)     {
        math::XYZVector mainAxis(axis_);
        mainAxis.unit();
        math::XYZVector phiAxis(barycenter_.x(), barycenter_.y(), 0);
        math::XYZVector udir(mainAxis.Cross(phiAxis));
        udir = udir.unit();
        trans_ = Transform3D(Point(barycenter_), Point(barycenter_ + axis_), Point(barycenter_ + udir), Point(0, 0, 0),
        Point(0., 0., 1.), Point(1., 0., 0.));
    }

    std::set<int> layers;
    for (const auto& spot : theSpots_) {
        if (spot.layer() > recHitTools_->lastLayerEE()) continue;
        if (!withHalo && (! spot.isCore() ))
            continue;
        if (initialCalculation) {
            // initial calculation, take only core hits
            if ( ! spot.isCore() ) continue;
            layers.insert(spot.layer());
            for (int i = 0; i < spot.multiplicity(); ++i)
                pca_->AddRow(spot.row());
        }
        else {
            // use a cylinder, include all hits
            math::XYZPoint local = trans_(Point( spot.row()[0],spot.row()[1],spot.row()[2]));
            if (local.Perp2() > radius2) continue;
            layers.insert(spot.layer());
            for (int i = 0; i < spot.multiplicity(); ++i)
                pca_->AddRow(spot.row());
        }
    }
    if (debug_)
        std::cout << " Nlayers " << layers.size() << std::endl;
    if (layers.size() < 3) {
        pcaIteration_ = -1;
        return;
    }
    pca_->MakePrincipals();
    ++pcaIteration_;
    const TVectorD& means = *(pca_->GetMeanValues());
    const TMatrixD& eigens = *(pca_->GetEigenVectors());

    barycenter_ = math::XYZPoint(means[0], means[1], means[2]);
    axis_ = math::XYZVector(eigens(0, 0), eigens(1, 0), eigens(2, 0));
    if (axis_.z() * barycenter_.z() < 0.0) {
        axis_ = -1. * axis_;
    }
}

 void EGammaPCAHelper::computeShowerWidth(float radius, bool withHalo){
    sigu_ = 0.;
    sigv_ = 0.;
    sigp_ = 0.;
    sige_ = 0.;
    double cyl_ene = 0.;

    float radius2 = radius * radius;
    for (const auto& spot : theSpots_) {
        Point globalPoint(spot.row()[0],spot.row()[1],spot.row()[2]);
        math::XYZPoint local = trans_(globalPoint);
        if (local.Perp2() > radius2) continue;

        // Select halo hits or not
        if (withHalo && spot.fraction() < 0) continue;
        if (!withHalo && !(spot.isCore())) continue;

        sige_ += (globalPoint.eta() - theCluster_->eta()) * (globalPoint.eta() - theCluster_->eta()) * spot.energy();
        sigp_ += deltaPhi(globalPoint.phi(), theCluster_->phi()) * deltaPhi(globalPoint.phi(), theCluster_->phi()) *
              spot.energy();

        sigu_ += local.x() * local.x() * spot.energy();
        sigv_ += local.y() * local.y() * spot.energy();
        cyl_ene += spot.energy();
    }

  if (cyl_ene > 0.) {
    const double inv_cyl_ene = 1. / cyl_ene;
    sigu_ = sigu_ * inv_cyl_ene;
    sigv_ = sigv_ * inv_cyl_ene;
    sigp_ = sigp_ * inv_cyl_ene;
    sige_ = sige_ * inv_cyl_ene;
  }
  sigu_ = std::sqrt(sigu_);
  sigv_ = std::sqrt(sigv_);
  sigp_ = std::sqrt(sigp_);
  sige_ = std::sqrt(sige_);
}

bool EGammaPCAHelper::checkIteration() const {
    if (pcaIteration_ == 0) {
        if(debug_)
            std::cout << " The PCA has not been run yet " << std::endl;
        return false;
    }   else if (pcaIteration_ == 1) {
        if (debug_)
            std::cout << " The PCA has been run only once - careful " << std::endl;
        return false;
    }   else if (pcaIteration_ == -1){
        if (debug_)
            std::cout << " Not enough layers to perform PCA " << std::endl;
        return false;
    }
    return true;
}

void EGammaPCAHelper::clear() {
    theSpots_.clear();
    pcaIteration_ = 0;
    sigu_ = 0.;
    sigv_ = 0.;
    sigp_ = 0.;
    sige_ = 0.;
}

LongDeps  EGammaPCAHelper::energyPerLayer(float radius, bool withHalo) {
    if (debug_) checkIteration();
    std::set<int> layers;
    float radius2 = radius*radius;
    std::vector<float> energyPerLayer(HGCalImagingAlgo::maxlayer+1, 0.f);
    math::XYZVector mainAxis(axis_);
    mainAxis.unit();
    math::XYZVector phiAxis(barycenter_.x(), barycenter_.y(), 0);
    math::XYZVector udir(mainAxis.Cross(phiAxis));
    udir = udir.unit();
    trans_ = Transform3D(Point(barycenter_), Point(barycenter_ + axis_), Point(barycenter_ + udir), Point(0, 0, 0),
    Point(0., 0., 1.), Point(1., 0., 0.));
    float energyEE = 0.;
    float energyFH = 0.;
    float energyBH = 0.;

    for (const auto& spot : theSpots_) {
        if (!withHalo && ! spot.isCore())
            continue;
        math::XYZPoint local = trans_(Point( spot.row()[0],spot.row()[1],spot.row()[2]));
        if (local.Perp2() > radius2) continue;
        energyPerLayer[spot.layer()] += spot.energy();
        layers.insert(spot.layer());
        if (spot.subdet() == HGCEE) { energyEE += spot.energy();}
        else if (spot.subdet() == HGCHEF) { energyFH += spot.energy();}
        else if (spot.subdet() == HGCHEB) { energyBH += spot.energy();}

    }
    return LongDeps(radius,energyPerLayer,energyEE,energyFH,energyBH,layers);
}

void EGammaPCAHelper::printHits(float radius) const {
    unsigned nSpots = theSpots_.size();
    float radius2=radius*radius;
    for ( unsigned i =0; i< nSpots ; ++i) {
        Spot spot(theSpots_[i]);
        math::XYZPoint local = trans_(Point( spot.row()[0],spot.row()[1],spot.row()[2]));
        if (local.Perp2() < radius2 ) {
            std::cout << i << "  " << theSpots_[i].detId().rawId() << " " << theSpots_[i].layer() << " " << theSpots_[i].energy() << " " <<theSpots_[i].isCore() ;
            std::cout << " " << std::sqrt(local.Perp2()) << std::endl;
        }
    }
}

float EGammaPCAHelper::findZFirstLayer(const LongDeps & ld) const {
    unsigned int firstLayer = 0;
    for(unsigned il=1;il<=HGCalImagingAlgo::maxlayer;++il) {
        if (ld.energyPerLayer()[il] > 0.) {
            firstLayer = il;
            break;
        }
    }
    // Make dummy DetId to get abs(z) for layer
    DetId id;
    if (firstLayer <= recHitTools_->lastLayerEE()) id = HGCalDetId(ForwardSubdetector::HGCEE, 1, firstLayer, 1, 50, 1);
    else if (firstLayer <= recHitTools_->lastLayerFH()) id = HGCalDetId(ForwardSubdetector::HGCHEF, 1, firstLayer - recHitTools_->lastLayerEE(), 1, 50, 1);
    else  id = HcalDetId(HcalSubdetector::HcalEndcap, 50, 100, firstLayer - recHitTools_->lastLayerFH());
    return recHitTools_->getPosition(id).z();
}

float EGammaPCAHelper::clusterDepthCompatibility(const LongDeps & ld, float & measuredDepth, float& expectedDepth, float&expectedSigma) {
    expectedDepth = -999.;
    expectedSigma = -999.;
    measuredDepth = -999.;
    if (!checkIteration()) return -999.;

    float z = findZFirstLayer(ld);
    math::XYZVector dir=axis_.unit();
    measuredDepth = std::abs((z-std::abs(barycenter_.z()))/dir.z());
    return showerDepth_.getClusterDepthCompatibility(measuredDepth,ld.energyEE(), expectedDepth,expectedSigma);
}