SiStripRecHitMatcher.cc

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// File: SiStripRecHitMatcher.cc
// Description:  Matches into rechits
// Author:  C.Genta
#include "RecoLocalTracker/SiStripRecHitConverter/interface/SiStripRecHitMatcher.h"
#include "DataFormats/GeometryVector/interface/GlobalPoint.h"
#include "Geometry/CommonDetUnit/interface/GluedGeomDet.h"
#include "Geometry/TrackerGeometryBuilder/interface/StripGeomDetUnit.h"
#include "DataFormats/CLHEP/interface/AlgebraicObjects.h"

#include "TrackingTools/TransientTrackingRecHit/interface/HelpertRecHit2DLocalPos.h"
#include <boost/bind.hpp>

#include <DataFormats/TrackingRecHit/interface/AlignmentPositionError.h>

SiStripRecHitMatcher::SiStripRecHitMatcher(const edm::ParameterSet& conf)
    : scale_(conf.getParameter<double>("NSigmaInside")),
      preFilter_(conf.existsAs<bool>("PreFilter") ? conf.getParameter<bool>("PreFilter") : false) {}

SiStripRecHitMatcher::SiStripRecHitMatcher(const double theScale) : scale_(theScale) {}

namespace {
  // FIXME for c++0X
  inline void pb1(std::vector<SiStripMatchedRecHit2D*>& v, SiStripMatchedRecHit2D* h) { v.push_back(h); }
  inline void pb2(SiStripRecHitMatcher::CollectorMatched& v, const SiStripMatchedRecHit2D& h) { v.push_back(h); }

}  // namespace

// needed by the obsolete version still in use on some architectures
void SiStripRecHitMatcher::match(const SiStripRecHit2D* monoRH,
                                 SimpleHitIterator begin,
                                 SimpleHitIterator end,
                                 edm::OwnVector<SiStripMatchedRecHit2D>& collector,
                                 const GluedGeomDet* gluedDet,
                                 LocalVector trackdirection) const {
  std::vector<SiStripMatchedRecHit2D*> result;
  result.reserve(end - begin);
  match(monoRH, begin, end, result, gluedDet, trackdirection);
  for (std::vector<SiStripMatchedRecHit2D*>::iterator p = result.begin(); p != result.end(); p++)
    collector.push_back(*p);
}

void SiStripRecHitMatcher::match(const SiStripRecHit2D* monoRH,
                                 SimpleHitIterator begin,
                                 SimpleHitIterator end,
                                 std::vector<SiStripMatchedRecHit2D*>& collector,
                                 const GluedGeomDet* gluedDet,
                                 LocalVector trackdirection) const {
  Collector result(boost::bind(&pb1, boost::ref(collector), boost::bind(&SiStripMatchedRecHit2D::clone, _1)));
  match(monoRH, begin, end, result, gluedDet, trackdirection);
}

void SiStripRecHitMatcher::match(const SiStripRecHit2D* monoRH,
                                 SimpleHitIterator begin,
                                 SimpleHitIterator end,
                                 CollectorMatched& collector,
                                 const GluedGeomDet* gluedDet,
                                 LocalVector trackdirection) const {
  Collector result(boost::bind(pb2, boost::ref(collector), _1));
  match(monoRH, begin, end, result, gluedDet, trackdirection);
}

// this is the one used by the RecHitConverter
void SiStripRecHitMatcher::match(const SiStripRecHit2D* monoRH,
                                 RecHitIterator begin,
                                 RecHitIterator end,
                                 CollectorMatched& collector,
                                 const GluedGeomDet* gluedDet,
                                 LocalVector trackdirection) const {
  // is this really needed now????
  SimpleHitCollection stereoHits;
  stereoHits.reserve(end - begin);
  for (RecHitIterator i = begin; i != end; ++i)
    stereoHits.push_back(&(*i));  // convert to simple pointer

  return match(monoRH, stereoHits.begin(), stereoHits.end(), collector, gluedDet, trackdirection);
}

// the "real implementation"
void SiStripRecHitMatcher::match(const SiStripRecHit2D* monoRH,
                                 SimpleHitIterator begin,
                                 SimpleHitIterator end,
                                 Collector& collector,
                                 const GluedGeomDet* gluedDet,
                                 LocalVector trackdirection) const {
  // stripdet = mono
  // partnerstripdet = stereo
  const GeomDetUnit* stripdet = gluedDet->monoDet();
  const GeomDetUnit* partnerstripdet = gluedDet->stereoDet();
  const StripTopology& topol = (const StripTopology&)stripdet->topology();

  // position of the initial and final point of the strip (RPHI cluster) in local strip coordinates
  double RPHIpointX = topol.measurementPosition(monoRH->localPositionFast()).x();
  MeasurementPoint RPHIpointini(RPHIpointX, -0.5);
  MeasurementPoint RPHIpointend(RPHIpointX, 0.5);

  // position of the initial and final point of the strip in local coordinates (mono det)
  StripPosition stripmono = StripPosition(topol.localPosition(RPHIpointini), topol.localPosition(RPHIpointend));

  // in case of no track hypothesis assume a track from the origin through the center of the strip
  if (trackdirection.mag2() < FLT_MIN) {
    const LocalPoint& lcenterofstrip = monoRH->localPositionFast();
    GlobalPoint gcenterofstrip = (stripdet->surface()).toGlobal(lcenterofstrip);
    GlobalVector gtrackdirection = gcenterofstrip - GlobalPoint(0, 0, 0);
    trackdirection = (gluedDet->surface()).toLocal(gtrackdirection);
  }

  //project mono hit on glued det
  StripPosition projectedstripmono = project(stripdet, gluedDet, stripmono, trackdirection);
  const StripTopology& partnertopol = (const StripTopology&)partnerstripdet->topology();

  double m00 = -(projectedstripmono.second.y() - projectedstripmono.first.y());
  double m01 = (projectedstripmono.second.x() - projectedstripmono.first.x());
  double c0 = m01 * projectedstripmono.first.y() + m00 * projectedstripmono.first.x();

  //error calculation (the part that depends on mono RH only)
  //  LocalVector  RPHIpositiononGluedendvector=projectedstripmono.second-projectedstripmono.first;
  /*
  double l1 = 1./RPHIpositiononGluedendvector.perp2();
  double c1 = RPHIpositiononGluedendvector.y();
  double s1 =-RPHIpositiononGluedendvector.x();
  */
  double c1 = -m00;
  double s1 = -m01;
  double l1 = 1. / (c1 * c1 + s1 * s1);

  double sigmap12 = sigmaPitch(monoRH->localPosition(), monoRH->localPositionError(), topol);
  // auto sigmap12 = monoRH->sigmaPitch();
  // assert(sigmap12>=0);

  SimpleHitIterator seconditer;

  for (seconditer = begin; seconditer != end; ++seconditer) {  //iterate on stereo rechits

    // position of the initial and final point of the strip (STEREO cluster)
    double STEREOpointX = partnertopol.measurementPosition((*seconditer)->localPositionFast()).x();
    MeasurementPoint STEREOpointini(STEREOpointX, -0.5);
    MeasurementPoint STEREOpointend(STEREOpointX, 0.5);

    // position of the initial and final point of the strip in local coordinates (stereo det)
    StripPosition stripstereo(partnertopol.localPosition(STEREOpointini), partnertopol.localPosition(STEREOpointend));

    //project stereo hit on glued det
    StripPosition projectedstripstereo = project(partnerstripdet, gluedDet, stripstereo, trackdirection);

    double m10 = -(projectedstripstereo.second.y() - projectedstripstereo.first.y());
    double m11 = (projectedstripstereo.second.x() - projectedstripstereo.first.x());

    //perform the matching
    //(x2-x1)(y-y1)=(y2-y1)(x-x1)
    AlgebraicMatrix22 m;
    AlgebraicVector2 c;  // FIXME understand why moving this initializer out of the loop changes the output!
    m(0, 0) = m00;
    m(0, 1) = m01;
    m(1, 0) = m10;
    m(1, 1) = m11;
    c(0) = c0;
    c(1) = m11 * projectedstripstereo.first.y() + m10 * projectedstripstereo.first.x();
    m.Invert();
    AlgebraicVector2 solution = m * c;
    LocalPoint position(solution(0), solution(1));

    /*
    {
      double m00 = -(projectedstripmono.second.y()-projectedstripmono.first.y()); 
      double m01 =  (projectedstripmono.second.x()-projectedstripmono.first.x());
      double m10 = -(projectedstripstereo.second.y()-projectedstripstereo.first.y()); 
      double m11 =  (projectedstripstereo.second.x()-projectedstripstereo.first.x());
      double c0  =  m01*projectedstripmono.first.y()   + m00*projectedstripmono.first.x();
      double c1  =  m11*projectedstripstereo.first.y() + m10*projectedstripstereo.first.x();
      
      double invDet = 1./(m00*m11-m10*m01);
    }
    */

    //
    // temporary fix by tommaso
    //

    LocalError tempError(100, 0, 100);
    if (!((gluedDet->surface()).bounds().inside(position, tempError, scale_)))
      continue;

    // then calculate the error
    /*
    LocalVector  stereopositiononGluedendvector=projectedstripstereo.second-projectedstripstereo.first;
    double l2 = 1./stereopositiononGluedendvector.perp2();
    double c2 = stereopositiononGluedendvector.y(); 
    double s2 =-stereopositiononGluedendvector.x();
    */

    double c2 = -m10;
    double s2 = -m11;
    double l2 = 1. / (c2 * c2 + s2 * s2);

    double sigmap22 = sigmaPitch((*seconditer)->localPosition(), (*seconditer)->localPositionError(), partnertopol);
    // auto sigmap22 = (*seconditer)->sigmaPitch();
    // assert(sigmap22>=0);

    double diff = (c1 * s2 - c2 * s1);
    double invdet2 = 1 / (diff * diff * l1 * l2);
    float xx = invdet2 * (sigmap12 * s2 * s2 * l2 + sigmap22 * s1 * s1 * l1);
    float xy = -invdet2 * (sigmap12 * c2 * s2 * l2 + sigmap22 * c1 * s1 * l1);
    float yy = invdet2 * (sigmap12 * c2 * c2 * l2 + sigmap22 * c1 * c1 * l1);
    LocalError error(xx, xy, yy);

    if ((gluedDet->surface()).bounds().inside(position, error, scale_)) {  //if it is inside the gluedet bonds
      //Change NSigmaInside in the configuration file to accept more hits
      //...and add it to the Rechit collection

      const SiStripRecHit2D* secondHit = *seconditer;
      collector(SiStripMatchedRecHit2D(position, error, *gluedDet, monoRH, secondHit));
    }
  }
}

SiStripRecHitMatcher::StripPosition SiStripRecHitMatcher::project(const GeomDetUnit* det,
                                                                  const GluedGeomDet* glueddet,
                                                                  StripPosition strip,
                                                                  LocalVector trackdirection) const {
  GlobalPoint globalpointini = (det->surface()).toGlobal(strip.first);
  GlobalPoint globalpointend = (det->surface()).toGlobal(strip.second);

  // position of the initial and final point of the strip in glued local coordinates
  LocalPoint positiononGluedini = (glueddet->surface()).toLocal(globalpointini);
  LocalPoint positiononGluedend = (glueddet->surface()).toLocal(globalpointend);

  //correct the position with the track direction

  float scale = -positiononGluedini.z() / trackdirection.z();

  LocalPoint projpositiononGluedini = positiononGluedini + scale * trackdirection;
  LocalPoint projpositiononGluedend = positiononGluedend + scale * trackdirection;

  return StripPosition(projpositiononGluedini, projpositiononGluedend);
}

//match a single hit
std::unique_ptr<SiStripMatchedRecHit2D> SiStripRecHitMatcher::match(const SiStripRecHit2D* monoRH,
                                                                    const SiStripRecHit2D* stereoRH,
                                                                    const GluedGeomDet* gluedDet,
                                                                    LocalVector trackdirection,
                                                                    bool force) const {
  // stripdet = mono
  // partnerstripdet = stereo
  const GeomDetUnit* stripdet = gluedDet->monoDet();
  const GeomDetUnit* partnerstripdet = gluedDet->stereoDet();
  const StripTopology& topol = (const StripTopology&)stripdet->topology();

  // position of the initial and final point of the strip (RPHI cluster) in local strip coordinates
  auto RPHIpointX = topol.measurementPosition(monoRH->localPositionFast()).x();
  MeasurementPoint RPHIpointini(RPHIpointX, -0.5f);
  MeasurementPoint RPHIpointend(RPHIpointX, 0.5f);

  // position of the initial and final point of the strip in local coordinates (mono det)
  StripPosition stripmono = StripPosition(topol.localPosition(RPHIpointini), topol.localPosition(RPHIpointend));

  // in case of no track hypothesis assume a track from the origin through the center of the strip
  if (trackdirection.mag2() < FLT_MIN) {
    const LocalPoint& lcenterofstrip = monoRH->localPositionFast();
    GlobalPoint gcenterofstrip = (stripdet->surface()).toGlobal(lcenterofstrip);
    GlobalVector gtrackdirection = gcenterofstrip - GlobalPoint(0, 0, 0);
    trackdirection = (gluedDet->surface()).toLocal(gtrackdirection);
  }

  //project mono hit on glued det
  StripPosition projectedstripmono = project(stripdet, gluedDet, stripmono, trackdirection);
  const StripTopology& partnertopol = (const StripTopology&)partnerstripdet->topology();

  double m00 = -(projectedstripmono.second.y() - projectedstripmono.first.y());
  double m01 = (projectedstripmono.second.x() - projectedstripmono.first.x());
  double c0 = m01 * projectedstripmono.first.y() + m00 * projectedstripmono.first.x();

  //error calculation (the part that depends on mono RH only)
  //  LocalVector  RPHIpositiononGluedendvector=projectedstripmono.second-projectedstripmono.first;
  /*
  double l1 = 1./RPHIpositiononGluedendvector.perp2();
  double c1 = RPHIpositiononGluedendvector.y();
  double s1 =-RPHIpositiononGluedendvector.x();
  */
  double c1 = -m00;
  double s1 = -m01;
  double l1 = 1. / (c1 * c1 + s1 * s1);

  double sigmap12 = sigmaPitch(monoRH->localPosition(), monoRH->localPositionError(), topol);
  // auto sigmap12 = monoRH->sigmaPitch();
  // assert(sigmap12>=0);

  // position of the initial and final point of the strip (STEREO cluster)
  auto STEREOpointX = partnertopol.measurementPosition(stereoRH->localPositionFast()).x();
  MeasurementPoint STEREOpointini(STEREOpointX, -0.5f);
  MeasurementPoint STEREOpointend(STEREOpointX, 0.5f);

  // position of the initial and final point of the strip in local coordinates (stereo det)
  StripPosition stripstereo(partnertopol.localPosition(STEREOpointini), partnertopol.localPosition(STEREOpointend));

  //project stereo hit on glued det
  StripPosition projectedstripstereo = project(partnerstripdet, gluedDet, stripstereo, trackdirection);

  double m10 = -(projectedstripstereo.second.y() - projectedstripstereo.first.y());
  double m11 = (projectedstripstereo.second.x() - projectedstripstereo.first.x());

  //perform the matching
  //(x2-x1)(y-y1)=(y2-y1)(x-x1)
  AlgebraicMatrix22 m(ROOT::Math::SMatrixNoInit{});
  AlgebraicVector2 c(c0, m11 * projectedstripstereo.first.y() + m10 * projectedstripstereo.first.x());
  m(0, 0) = m00;
  m(0, 1) = m01;
  m(1, 0) = m10;
  m(1, 1) = m11;
  m.Invert();
  AlgebraicVector2 solution = m * c;
  Local2DPoint position(solution(0), solution(1));

  if ((!force) && (!((gluedDet->surface()).bounds().inside(position, 10.f * scale_))))
    return std::unique_ptr<SiStripMatchedRecHit2D>(nullptr);

  double c2 = -m10;
  double s2 = -m11;
  double l2 = 1. / (c2 * c2 + s2 * s2);

  double sigmap22 = sigmaPitch(stereoRH->localPosition(), stereoRH->localPositionError(), partnertopol);
  // auto sigmap22 = stereoRH->sigmaPitch();
  // assert (sigmap22>0);

  double diff = (c1 * s2 - c2 * s1);
  double invdet2 = 1 / (diff * diff * l1 * l2);
  float xx = invdet2 * (sigmap12 * s2 * s2 * l2 + sigmap22 * s1 * s1 * l1);
  float xy = -invdet2 * (sigmap12 * c2 * s2 * l2 + sigmap22 * c1 * s1 * l1);
  float yy = invdet2 * (sigmap12 * c2 * c2 * l2 + sigmap22 * c1 * c1 * l1);
  LocalError error(xx, xy, yy);

  //if it is inside the gluedet bonds
  //Change NSigmaInside in the configuration file to accept more hits
  if (force || (gluedDet->surface()).bounds().inside(position, error, scale_))
    return std::make_unique<SiStripMatchedRecHit2D>(LocalPoint(position), error, *gluedDet, monoRH, stereoRH);
  return std::unique_ptr<SiStripMatchedRecHit2D>(nullptr);
}