#include <HIPixelClusterVtxProducer.h>

Inheritance diagram for HIPixelClusterVtxProducer:

Classes
struct	VertexHit
Public Member Functions
	HIPixelClusterVtxProducer (const edm::ParameterSet &ps)
	~HIPixelClusterVtxProducer ()
Private Member Functions
int	getContainedHits (const std::vector< VertexHit > &hits, double z0, double &chi)
virtual void	produce (edm::Event &ev, const edm::EventSetup &es)
Private Attributes
double	maxZ_
double	minZ_
std::string	srcPixels_
double	zStep_

Detailed Description

Definition at line 11 of file HIPixelClusterVtxProducer.h.

Constructor & Destructor Documentation

HIPixelClusterVtxProducer::HIPixelClusterVtxProducer ( const edm::ParameterSet & ps ) [explicit]

Definition at line 32 of file HIPixelClusterVtxProducer.cc.

  : srcPixels_(ps.getParameter<std::string>("pixelRecHits")),
    minZ_(ps.getParameter<double>("minZ")),
    maxZ_(ps.getParameter<double>("maxZ")),
    zStep_(ps.getParameter<double>("zStep"))

{
  // Constructor
  produces<reco::VertexCollection>();
}

HIPixelClusterVtxProducer::~HIPixelClusterVtxProducer ( )

Definition at line 45 of file HIPixelClusterVtxProducer.cc.

{ 
  // Destructor
}

Member Function Documentation

int HIPixelClusterVtxProducer::getContainedHits	(	const std::vector< VertexHit > &	hits,
		double	z0,
		double &	chi
	)		`[private]`

Definition at line 142 of file HIPixelClusterVtxProducer.cc.

References n, AlCaHLTBitMon_ParallelJobs::p, and hit::z.

Referenced by produce().

{
  // Calculate number of hits contained in v-shaped window in cluster y-width vs. z-position.
  int n = 0;
  chi   = 0.;

  for(std::vector<VertexHit>::const_iterator hit = hits.begin(); hit!= hits.end(); hit++) {
    double p = 2 * fabs(hit->z - z0)/hit->r + 0.5; // FIXME
    if(TMath::Abs(p - hit->w) <= 1.) { 
      chi += fabs(p - hit->w);
      n++;
    }
  }
  return n;
}

void HIPixelClusterVtxProducer::produce	(	edm::Event &	ev,
		const edm::EventSetup &	es
	)		`[private, virtual]`

Implements edm::EDProducer.

Definition at line 52 of file HIPixelClusterVtxProducer.cc.

References edmNew::DetSetVector< T >::data(), end, edm::EventSetup::get(), edm::Event::getByLabel(), getContainedHits(), TrackerGeometry::idToDet(), PixelTopology::isItEdgePixelInX(), PixelTopology::isItEdgePixelInY(), edm::HandleBase::isValid(), LogTrace, maxZ_, minZ_, PixelSubdetector::PixelBarrel, edm::ESHandle< T >::product(), edm::Handle< T >::product(), edm::Event::put(), HIPixelClusterVtxProducer::VertexHit::r, PixelGeomDetUnit::specificTopology(), srcPixels_, GeomDet::toGlobal(), HIPixelClusterVtxProducer::VertexHit::w, hit::x, hit::y, HIPixelClusterVtxProducer::VertexHit::z, hit::z, and zStep_.

{

  // new vertex collection
  std::auto_ptr<reco::VertexCollection> vertices(new reco::VertexCollection);

  // get pixel rechits
  edm::Handle<SiPixelRecHitCollection> hRecHits;
  try {
    ev.getByLabel(edm::InputTag(srcPixels_),hRecHits);
  } catch (...) {}

  // get tracker geometry
  if (hRecHits.isValid()) {
    edm::ESHandle<TrackerGeometry> trackerHandle;
    es.get<TrackerDigiGeometryRecord>().get(trackerHandle);
    const TrackerGeometry *tgeo = trackerHandle.product();
    const SiPixelRecHitCollection *hits = hRecHits.product();

    // loop over pixel rechits
    std::vector<VertexHit> vhits;
    for(SiPixelRecHitCollection::DataContainer::const_iterator hit = hits->data().begin(), 
          end = hits->data().end(); hit != end; ++hit) {
      if (!hit->isValid())
        continue;
      DetId id(hit->geographicalId());
      if(id.subdetId() != int(PixelSubdetector::PixelBarrel))
        continue;
      const PixelGeomDetUnit *pgdu = static_cast<const PixelGeomDetUnit*>(tgeo->idToDet(id));
      if (1) {
        const PixelTopology *pixTopo = &(pgdu->specificTopology());
        std::vector<SiPixelCluster::Pixel> pixels(hit->cluster()->pixels());
        bool pixelOnEdge = false;
        for(std::vector<SiPixelCluster::Pixel>::const_iterator pixel = pixels.begin(); 
            pixel != pixels.end(); ++pixel) {
          int pixelX = pixel->x;
          int pixelY = pixel->y;
          if(pixTopo->isItEdgePixelInX(pixelX) || pixTopo->isItEdgePixelInY(pixelY)) {
            pixelOnEdge = true;
            break;
          }
        }
        if (pixelOnEdge)
          continue;
      }

      LocalPoint lpos = LocalPoint(hit->localPosition().x(),
                                   hit->localPosition().y(),
                                   hit->localPosition().z());
      GlobalPoint gpos = pgdu->toGlobal(lpos);
      VertexHit vh;
      vh.z = gpos.z(); 
      vh.r = gpos.perp(); 
      vh.w = hit->cluster()->sizeY();
      vhits.push_back(vh);
    }
    
    // estimate z-position from cluster lengths
    double zest = 0.0;
    int nhits = 0, nhits_max = 0;
    double chi = 0, chi_max = 1e+9;
    for(double z0 = minZ_; z0 <= maxZ_; z0 += zStep_) {
      nhits = getContainedHits(vhits, z0, chi);
      if(nhits == 0) 
        continue;
      if(nhits > nhits_max) { 
        chi_max = 1e+9; 
        nhits_max = nhits; 
      }
      if(nhits >= nhits_max && chi < chi_max) {
        chi_max = chi; 
        zest = z0;   
      }
    } 

    LogTrace("MinBiasTracking")
      << "  [vertex position] estimated = " << zest 
      << " | pixel barrel hits = " << vhits.size();

    // put 1-d vertex and dummy errors into collection
    reco::Vertex::Error err;
    err(2,2) = 0.6 * 0.6;
    reco::Vertex ver(reco::Vertex::Point(0,0,zest), err, 0, 1, 1);
    vertices->push_back(ver);
  }

  ev.put(vertices);
}