ME0SegAlgoRU.cc

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#include "ME0SegAlgoRU.h"
#include "MuonSegFit.h"
#include "Geometry/GEMGeometry/interface/ME0Layer.h"
#include "DataFormats/GeometryVector/interface/GlobalPoint.h"
#include "DataFormats/Math/interface/deltaPhi.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

#include <algorithm>
#include <cmath>
#include <iostream>
#include <string>

#include <Math/Functions.h>
#include <Math/SVector.h>
#include <Math/SMatrix.h>



ME0SegAlgoRU::ME0SegAlgoRU(const edm::ParameterSet& ps)
: ME0SegmentAlgorithmBase(ps), myName("ME0SegAlgoRU") {

    allowWideSegments = ps.getParameter<bool>("allowWideSegments");
    doCollisions = ps.getParameter<bool>("doCollisions");

    stdParameters.maxChi2Additional = ps.getParameter<double>("maxChi2Additional");
    stdParameters.maxChi2Prune      = ps.getParameter<double>("maxChi2Prune"     );
    stdParameters.maxChi2GoodSeg    = ps.getParameter<double>("maxChi2GoodSeg"   ) ;
    stdParameters.maxPhiSeeds       = ps.getParameter<double>("maxPhiSeeds"      ) ;
    stdParameters.maxPhiAdditional  = ps.getParameter<double>("maxPhiAdditional" );
    stdParameters.maxETASeeds       = ps.getParameter<double>("maxETASeeds"      );
    stdParameters.maxTOFDiff        = ps.getParameter<double>("maxTOFDiff"      );
    stdParameters.requireCentralBX  = ps.getParameter<bool>("requireCentralBX"      );
    stdParameters.minNumberOfHits   = ps.getParameter<unsigned int>("minNumberOfHits"      );
    stdParameters.requireBeamConstr = true;

    wideParameters = stdParameters;
    wideParameters.maxChi2Prune     *=2;
    wideParameters.maxChi2GoodSeg   *=2;
    wideParameters.maxPhiSeeds      *=2;
    wideParameters.maxPhiAdditional *=2;
    wideParameters.minNumberOfHits  +=1;


    displacedParameters = stdParameters;
    displacedParameters.maxChi2Additional *= 2;
    displacedParameters.maxChi2Prune      = 100;
    displacedParameters.maxChi2GoodSeg    *= 5;
    displacedParameters.maxPhiSeeds       *=2;
    displacedParameters.maxPhiAdditional  *=2;
    displacedParameters.maxETASeeds       *=2;
    displacedParameters.requireBeamConstr = false;


    LogDebug("ME0SegAlgoRU") << myName << " has algorithm cuts set to: \n"
            << "--------------------------------------------------------------------\n"
            << "allowWideSegments   = " <<allowWideSegments              << "\n"
            << "doCollisions        = " <<doCollisions                   << "\n"
            << "maxChi2Additional   = " <<stdParameters.maxChi2Additional<< "\n"
            << "maxChi2Prune        = " <<stdParameters.maxChi2Prune     << "\n"
            << "maxChi2GoodSeg      = " <<stdParameters.maxChi2GoodSeg   << "\n"
            << "maxPhiSeeds         = " <<stdParameters.maxPhiSeeds      << "\n"
            << "maxPhiAdditional    = " <<stdParameters.maxPhiAdditional << "\n"
            << "maxETASeeds         = " <<stdParameters.maxETASeeds      << "\n"
            << "maxTOFDiff          = " <<stdParameters.maxTOFDiff       << "\n"
            << std::endl;

    theChamber=nullptr;

}

std::vector<ME0Segment> ME0SegAlgoRU::run(const ME0Chamber * chamber, const HitAndPositionContainer& rechits){

#ifdef EDM_ML_DEBUG // have lines below only compiled when in debug mode
    ME0DetId chId(chamber->id());
    edm::LogVerbatim("ME0SegAlgoRU") << "[ME0SegmentAlgorithm::run] build segments in chamber " << chId << " which contains "<<rechits.size()<<" rechits";
    for(unsigned int iH = 0; iH < rechits.size(); ++iH){
        auto me0id = rechits[iH].rh->me0Id();
        auto rhLP  = rechits[iH].lp;
        edm::LogVerbatim("ME0SegAlgoRU") << "[RecHit :: Loc x = "<<std::showpos<<std::setw(9)<<rhLP.x()<<" Glb y = "<<std::showpos<<std::setw(9)<<rhLP.y()<<" Time = "<<std::showpos<<rechits[iH].rh->tof()<<" -- "<<me0id.rawId()<<" = "<<me0id<<" ]"<<std::endl;
    }
#endif


    if (rechits.size() < 3 || rechits.size()>300){
        return std::vector<ME0Segment>();
    }

    theChamber = chamber;

    std::vector<unsigned int> recHits_per_layer(6,0);
    for(unsigned int iH = 0; iH < rechits.size(); ++iH) {
        recHits_per_layer[rechits[iH].layer-1]++;
    }

    BoolContainer used(rechits.size(),false);

    // We have at least 2 hits. We intend to try all possible pairs of hits to start
    // segment building. 'All possible' means each hit lies on different layers in the chamber.
    // after all same size segs are build we get rid of the overcrossed segments using the chi2 criteria
    // the hits from the segs that are left are marked as used and are not added to segs in future iterations
    // the hits from 3p segs are marked as used separately in order to try to assamble them in longer segments
    // in case there is a second pass

    // Choose first hit (as close to IP as possible) h1 and second hit
    // (as far from IP as possible) h2 To do this we iterate over hits
    // in the chamber by layer - pick two layers.  Then we
    // iterate over hits within each of these layers and pick h1 and h2
    // these.  If they are 'close enough' we build an empty
    // segment.  Then try adding hits to this segment.

    std::vector<ME0Segment> segments;

    auto doStd = [&] () {
        for(unsigned int n_seg_min = 6u; n_seg_min  >= stdParameters.minNumberOfHits; --n_seg_min)
            lookForSegments(stdParameters,n_seg_min,rechits,recHits_per_layer, used, segments);
    };
    auto doDisplaced = [&] () {
        for(unsigned int n_seg_min = 6u; n_seg_min  >= displacedParameters.minNumberOfHits; --n_seg_min)
            lookForSegments(displacedParameters,n_seg_min,rechits,recHits_per_layer, used,segments);
    };
    // Not currently used
    // auto doWide = [&] () {
    //  for(unsigned int n_seg_min = 6u; n_seg_min >= wideParameters.minNumberOfHits; --n_seg_min)
    //      lookForSegments(wideParameters,n_seg_min,rechits,recHits_per_layer, used,segments);
    // };
    auto printSegments = [&] {
#ifdef EDM_ML_DEBUG // have lines below only compiled when in debug mode
        for(unsigned int iS = 0; iS < segments.size(); ++iS) {
            const auto& seg = segments[iS];
            ME0DetId chId(seg.me0DetId());
            const auto& rechits = seg.specificRecHits();
            edm::LogVerbatim("ME0SegAlgoRU") << "[ME0SegAlgoRU] segment in chamber " << chId << " which contains "<<rechits.size()<<" rechits and with specs: \n"<<seg;
            for (auto rh=rechits.begin(); rh!=rechits.end(); ++rh){
                auto me0id = rh->me0Id();
                edm::LogVerbatim("ME0SegAlgoRU") << "[RecHit :: Loc x = "<<std::showpos<<std::setw(9)<<rh->localPosition().x()<<" Loc y = "<<std::showpos<<std::setw(9)<<rh->localPosition().y()<<" Time = "<<std::showpos<<rh->tof()<<" -- "<<me0id.rawId()<<" = "<<me0id<<" ]";
            }
        }
#endif
    };


    //If we arent doing collisions, do a single iteration
    if(!doCollisions){
        doDisplaced();
        printSegments();
        return segments;
    }

    //Iteration 1: STD processing
    doStd();

    if(false){
        //How the CSC algorithm ~does iterations. for now not considering
        //displaced muons will not worry about it  later
        //Iteration 2a: If we don't allow wide segments simply do displaced
        // Or if we already found a segment simply skip to displaced
        if(!allowWideSegments || !segments.empty()){
            doDisplaced();
            return segments;
        }
        //doWide();
        doDisplaced();
    }
    printSegments();
    return segments;
}

void ME0SegAlgoRU::lookForSegments( const SegmentParameters& params, const unsigned int n_seg_min,
        const HitAndPositionContainer& rechits, const std::vector<unsigned int>& recHits_per_layer,
        BoolContainer& used, std::vector<ME0Segment>& segments) const  {
    auto ib = rechits.begin();
    auto ie = rechits.end();
    std::vector<std::pair<float,HitAndPositionPtrContainer> > proto_segments;
    // the first hit is taken from the back
    for (auto i1 = ib; i1 != ie; ++i1) {
        const auto& h1 = *i1;

        //skip if rh is used and the layer tat has big rh multiplicity(>25RHs)
        if(used[h1.idx]) continue;
        if(recHits_per_layer[h1.layer-1]>100) continue;

        //      bool segok = false;
        // the second hit from the front
        for (auto i2 = ie-1; i2 != i1; --i2) {
            //          if(segok) break; //Currently turned off
            const auto& h2 = *i2;

            //skip if rh is used and the layer tat has big rh multiplicity(>25RHs)
            if(used[h2.idx]) continue;
            if(recHits_per_layer[h2.layer-1]>100) continue;

            //Stop if the distance between layers is not large enough
            if((std::abs(int(h2.layer) - int(h1.layer)) + 1) < int(n_seg_min)) break;

            if(std::fabs(h1.rh->tof()-h2.rh->tof()) > params.maxTOFDiff + 1.0 )continue;
            if(!areHitsCloseInEta(params.maxETASeeds, params.requireBeamConstr, h1.gp, h2.gp)) continue;
            if(!areHitsCloseInGlobalPhi(params.maxPhiSeeds,abs(int(h2.layer) - int(h1.layer)), h1.gp, h2.gp)) continue;

            HitAndPositionPtrContainer current_proto_segment;
            std::unique_ptr<MuonSegFit> current_fit;
            current_fit = addHit(current_proto_segment,h1);
            current_fit = addHit(current_proto_segment,h2);

            tryAddingHitsToSegment(params.maxTOFDiff,params.maxETASeeds, params.maxPhiAdditional, params.maxChi2Additional, current_fit,current_proto_segment, used,i1,i2);

            if(current_proto_segment.size() > n_seg_min)
                pruneBadHits(params.maxChi2Prune,current_proto_segment,current_fit,n_seg_min);

            edm::LogVerbatim("ME0SegAlgoRU") << "[ME0SegAlgoRU::lookForSegments] # of hits in segment " << current_proto_segment.size() <<" min # "<< n_seg_min <<" => "<< (current_proto_segment.size() >= n_seg_min) << " chi2/ndof "<<current_fit->chi2()/current_fit->ndof()<<" => "<<(current_fit->chi2()/current_fit->ndof() < params.maxChi2GoodSeg ) <<std::endl;

            if(current_proto_segment.size() < n_seg_min) continue;
            const float current_metric = current_fit->chi2()/current_fit->ndof();
            if(current_metric > params.maxChi2GoodSeg) continue;

            if(params.requireCentralBX){
                int nCentral = 0;
                int nNonCentral =0;
                for(const auto* rh : current_proto_segment ) {
                    if(std::fabs(rh->rh->tof())  < 2 ) nCentral++;
                    else nNonCentral++;
                }
                if(nNonCentral >= nCentral) continue;
            }
            //          segok = true;

            proto_segments.emplace_back( current_metric, current_proto_segment);
        }

    }
    addUniqueSegments(proto_segments,segments,used);

}

void ME0SegAlgoRU::addUniqueSegments(SegmentByMetricContainer& proto_segments, std::vector<ME0Segment>& segments,BoolContainer& used ) const {
    std::sort(proto_segments.begin(),proto_segments.end(),
            [](const std::pair<float,HitAndPositionPtrContainer> & a,
                    const std::pair<float,HitAndPositionPtrContainer> & b) { return a.first < b.first;});

    //Now add to the collect based on minChi2 marking the hits as used after
    std::vector<unsigned int> usedHits;
    for(unsigned int iS = 0; iS < proto_segments.size(); ++iS){
        HitAndPositionPtrContainer currentProtoSegment = proto_segments[iS].second;

        //check to see if we already used thes hits this round
        bool alreadyFilled=false;
        for(unsigned int iH = 0; iH < currentProtoSegment.size(); ++iH){
            for(unsigned int iOH = 0; iOH < usedHits.size(); ++iOH){
                if(usedHits[iOH]!=currentProtoSegment[iH]->idx) continue;
                alreadyFilled = true;
                break;
            }
        }
        if(alreadyFilled) continue;
        for(const auto* h : currentProtoSegment){
            usedHits.push_back(h->idx);
            used[h->idx] = true;
        }

        std::unique_ptr<MuonSegFit> current_fit = makeFit(currentProtoSegment);

        // Create an actual ME0Segment - retrieve all info from the fit
        // calculate the timing fron rec hits associated to the TrackingRecHits used
        // to fit the segment
        float averageTime=0.;
        for(const auto* h : currentProtoSegment){
            averageTime += h->rh->tof();
        }
        averageTime /= float(currentProtoSegment.size());
        float timeUncrt=0.;
        for(const auto* h : currentProtoSegment){
            timeUncrt += (h->rh->tof()-averageTime)*(h->rh->tof()-averageTime);
        }
        timeUncrt = std::sqrt(timeUncrt/float(currentProtoSegment.size()-1));

        std::sort(currentProtoSegment.begin(),currentProtoSegment.end(),
                [](const HitAndPosition* a, const HitAndPosition *b) {return a->layer < b->layer;}
        );

        std::vector<const ME0RecHit*> bareRHs; bareRHs.reserve(currentProtoSegment.size());
        for(const auto* rh : currentProtoSegment) bareRHs.push_back(rh->rh);
        const float dPhi = theChamber->computeDeltaPhi(current_fit->intercept(),current_fit->localdir());
        ME0Segment temp(bareRHs, current_fit->intercept(),
                current_fit->localdir(), current_fit->covarianceMatrix(), current_fit->chi2(), averageTime, timeUncrt, dPhi);
        segments.push_back(temp);


    }
}

void ME0SegAlgoRU::tryAddingHitsToSegment(const float maxTOF,  const float maxETA, const float maxPhi,const float maxChi2, std::unique_ptr<MuonSegFit>& current_fit, HitAndPositionPtrContainer& proto_segment,
        const BoolContainer& used, HitAndPositionContainer::const_iterator i1, HitAndPositionContainer::const_iterator i2) const {
    // Iterate over the layers with hits in the chamber
    // Skip the layers containing the segment endpoints
    // Test each hit on the other layers to see if it is near the segment
    // If it is, see whether there is already a hit on the segment from the same layer
    //    - if so, and there are more than 2 hits on the segment, copy the segment,
    //      replace the old hit with the new hit. If the new segment chi2 is better
    //      then replace the original segment with the new one (by swap)
    //    - if not, copy the segment, add the hit. If the new chi2/dof is still satisfactory
    //      then replace the original segment with the new one (by swap)

    //Hits are ordered by layer, "i1" is the inner hit and i2 is the outer hit
    //so possible hits to add must be between these two iterators
    for(auto iH = i1 + 1; iH != i2; ++iH ){
        if(iH->layer == i1->layer) continue;
        if(iH->layer == i2->layer) break;
        if(used[iH->idx]) continue;
        if(!areHitsConsistentInTime(maxTOF,proto_segment,*iH)) continue;
        if (!isHitNearSegment(maxETA,maxPhi,current_fit,proto_segment,*iH)) continue;
        if(hasHitOnLayer(proto_segment,iH->layer))
            compareProtoSegment(current_fit,proto_segment,*iH);
        else
            increaseProtoSegment(maxChi2, current_fit,proto_segment,*iH);
    }
}

bool ME0SegAlgoRU::areHitsCloseInEta(const float maxETA, const bool beamConst, const GlobalPoint& h1, const GlobalPoint& h2) const {
    float diff = 0;
    diff = std::fabs(h1.eta() - h1.eta());
    edm::LogVerbatim("ME0SegAlgoRU") << "[ME0SegAlgoRU::areHitsCloseInEta] gp1 = "<<h1<<" in eta part = "<<h1.eta() <<" and gp2 = "<<h2<<" in eta part = "<<h2.eta() <<" ==> dEta = "<<diff<<" ==> return "<<(diff < 0.1)<<std::endl;
    return (diff < std::max(maxETA,float(0.01)) ); //temp for floating point comparision...maxEta is the difference between partitions, so x1.5 to take into account non-circle geom.
}

bool ME0SegAlgoRU::areHitsCloseInGlobalPhi(const float maxPHI, const unsigned int nLayDisp, const GlobalPoint& h1, const GlobalPoint& h2) const {
    float dphi12 = deltaPhi(h1.barePhi(),h2.barePhi());
    edm::LogVerbatim("ME0SegAlgoRU") << "[ME0SegAlgoRU::areHitsCloseInGlobalPhi] gp1 = "<<h1<<" and gp2 = "<<h2<<" ==> dPhi = "<<dphi12<<" ==> return "<<(fabs(dphi12) < std::max(maxPHI,float(0.02)))<<std::endl;
    return fabs(dphi12) < std::max(maxPHI, float(float(nLayDisp)*0.004));
}

bool ME0SegAlgoRU::isHitNearSegment(const float maxETA, const float maxPHI,  const std::unique_ptr<MuonSegFit>& fit, const HitAndPositionPtrContainer& proto_segment, const HitAndPosition& h) const {
    //Get average eta, based on the two seeds...asssumes that we have not started pruning yet!
    const float avgETA = (proto_segment[1]->gp.eta() + proto_segment[0]->gp.eta())/2.;
    //  edm::LogVerbatim("ME0SegAlgoRU") << "[ME0SegAlgoRU::isHitNearSegment] average eta = "<<avgETA<<" additionalHit eta = "<<h.gp.eta() <<" ==> dEta = "<<std::fabs(h.gp.eta() - avgETA) <<" ==> return "<<(std::fabs(h.gp.eta() - avgETA) < std::max(maxETA,float(0.01) ))<<std::endl;
    if(std::fabs(h.gp.eta() - avgETA) > std::max(maxETA,float(0.01) )) return false;

    //Now check the dPhi based on the segment fit
    GlobalPoint globIntercept = globalAtZ(fit, h.lp.z());
    float dPhi = deltaPhi(h.gp.barePhi(),globIntercept.phi());
    //check to see if it is inbetween the two rolls of the outer and inner hits
    //  edm::LogVerbatim("ME0SegAlgoRU") << "[ME0SegAlgoRU::isHitNearSegment] projected phi = "<<globIntercept.phi()<<" additionalHit phi = "<<h.gp.barePhi() <<" ==> dPhi = "<<dPhi <<" ==> return "<<(std::fabs(dPhi) <  std::max(maxPHI,float(0.001)))<<std::endl;
    return (std::fabs(dPhi) <  std::max(maxPHI,float(0.001)));
}

bool ME0SegAlgoRU::areHitsConsistentInTime(const float maxTOF, const HitAndPositionPtrContainer& proto_segment, const HitAndPosition& h)  const {
    std::vector<float> tofs; tofs.reserve(proto_segment.size() + 1);
    tofs.push_back(h.rh->tof());
    for(const auto* ih : proto_segment) tofs.push_back(ih->rh->tof());
    std::sort(tofs.begin(),tofs.end());
    if(std::fabs(tofs.front() - tofs.back()) < maxTOF +1.0 ) return true;
    return false;
}

GlobalPoint ME0SegAlgoRU::globalAtZ(const std::unique_ptr<MuonSegFit>& fit, float z) const {
    float x = fit->xfit(z);
    float y = fit->yfit(z);
    return theChamber->toGlobal(LocalPoint(x,y,z));
}

std::unique_ptr<MuonSegFit> ME0SegAlgoRU::addHit( HitAndPositionPtrContainer& proto_segment, const HitAndPosition& aHit) const {
    proto_segment.push_back(&aHit);
    // make a fit
    return makeFit(proto_segment);
}

std::unique_ptr<MuonSegFit> ME0SegAlgoRU::makeFit(const HitAndPositionPtrContainer& proto_segment) const {
    // for ME0 we take the me0rechit from the proto_segment we transform into Tracking Rechits
    // the local rest frame is the ME0Chamber
    MuonSegFit::MuonRecHitContainer muonRecHits;
    for (auto rh=proto_segment.begin();rh<proto_segment.end(); rh++){
        ME0RecHit *newRH = (*rh)->rh->clone();
        newRH->setPosition((*rh)->lp);
        MuonSegFit::MuonRecHitPtr trkRecHit(newRH);
        muonRecHits.push_back(trkRecHit);
    }
    std::unique_ptr<MuonSegFit> currentFit(new MuonSegFit(muonRecHits));
    currentFit->fit();
    return currentFit;
}

void ME0SegAlgoRU::pruneBadHits(const float maxChi2, HitAndPositionPtrContainer& proto_segment,  std::unique_ptr<MuonSegFit>& fit, const unsigned int n_seg_min) const{
    while(proto_segment.size() > n_seg_min && fit->chi2()/fit->ndof()  > maxChi2){
        float maxDev = -1;
        HitAndPositionPtrContainer::iterator worstHit;
        for(auto it = proto_segment.begin(); it != proto_segment.end(); ++it){
            const float dev = getHitSegChi2(fit,*(*it)->rh);
            if(dev < maxDev) continue;
            maxDev = dev;
            worstHit = it;
        }
        edm::LogVerbatim("ME0SegAlgoRU") << "[ME0SegAlgoRU::pruneBadHits] pruning one hit-> layer: "<< (*worstHit)->layer <<" eta: "<< (*worstHit)->gp.eta() <<" phi: "<<(*worstHit)->gp.phi()<<" old chi2/dof: "<<fit->chi2()/fit->ndof() << std::endl;
        proto_segment.erase( worstHit);
        fit = makeFit(proto_segment);
    }
}

float ME0SegAlgoRU::getHitSegChi2(const std::unique_ptr<MuonSegFit>& fit, const ME0RecHit& hit) const{
    const auto lp = hit.localPosition();
    const auto le = hit.localPositionError();
    const float du = fit->xdev(lp.x(),lp.z());
    const float dv = fit->ydev(lp.y(),lp.z());

    ROOT::Math::SMatrix<double,2,2,ROOT::Math::MatRepSym<double,2> > IC;
    IC(0,0) = le.xx();
    IC(1,0) = le.xy();
    IC(1,1) = le.yy();

    // Invert covariance matrix
    IC.Invert();
    return du*du*IC(0,0) + 2.*du*dv*IC(0,1) + dv*dv*IC(1,1);
}

bool ME0SegAlgoRU::hasHitOnLayer(const HitAndPositionPtrContainer& proto_segment, const unsigned int layer) const {
    for(const auto* h : proto_segment) if(h->layer == layer) return true;
    return false;
}

void ME0SegAlgoRU::compareProtoSegment(std::unique_ptr<MuonSegFit>& current_fit, HitAndPositionPtrContainer& current_proto_segment, const HitAndPosition& new_hit) const {
    const HitAndPosition * old_hit = nullptr;
    HitAndPositionPtrContainer new_proto_segment = current_proto_segment;

    for (auto it = new_proto_segment.begin(); it != new_proto_segment.end();) {
        if ((*it)->layer == new_hit.layer) {
            old_hit = *it;
            it = new_proto_segment.erase(it);
        } else {
            ++it;
        }
    }
    if(old_hit == nullptr) return;
    auto new_fit = addHit(new_proto_segment,new_hit);

    //If on the same strip but different BX choose the closest
    bool useNew = false;
    if(old_hit->lp == new_hit.lp ){
        float avgtof = 0;
        for(const auto* h : current_proto_segment)
            if(old_hit != h) avgtof += h->rh->tof();
        avgtof /= float(current_proto_segment.size() - 1);
        if(std::abs(avgtof - new_hit.rh->tof() ) <
                std::abs(avgtof - old_hit->rh->tof() )
        ) useNew = true;
    } //otherwise base it on chi2
    else if(new_fit->chi2() < current_fit->chi2()) useNew = true;

    if(useNew){
        current_proto_segment = new_proto_segment;
        current_fit = std::move(new_fit);
    }

}

void ME0SegAlgoRU::increaseProtoSegment(const float maxChi2, std::unique_ptr<MuonSegFit>& current_fit, HitAndPositionPtrContainer& current_proto_segment, const HitAndPosition& new_hit) const {
    HitAndPositionPtrContainer new_proto_segment = current_proto_segment;
    auto new_fit = addHit(new_proto_segment,new_hit);
    //  edm::LogVerbatim("ME0SegAlgoRU") << "[ME0SegAlgoRU::increaseProtoSegment] new chi2 = "<<new_fit->chi2()<<" new chi2/dof = "<<new_fit->chi2()/new_fit->ndof() <<" ==> add: " << (new_fit->chi2()/new_fit->ndof() < maxChi2 ) <<std::endl;
    if(new_fit->chi2()/new_fit->ndof() < maxChi2 ){
        current_proto_segment = new_proto_segment;
        current_fit = std::move(new_fit);
    }
}