MTDThresholdClusterizer Class Reference

An explicit threshold-based clustering algorithm. More...

#include <MTDThresholdClusterizer.h>

Inheritance diagram for MTDThresholdClusterizer:

Public Member Functions
void	clusterize (const FTLRecHitCollection &input, const MTDGeometry *geom, const MTDTopology *topo, FTLClusterCollection &output) override
	Cluster hits. This method operates on a matrix of hits and finds the largest contiguous cluster around each seed hit. Input and output data stored in DetSet. More...
	MTDThresholdClusterizer (edm::ParameterSet const &conf)
	Constructor: More...
	~MTDThresholdClusterizer () override
Public Member Functions inherited from MTDClusterizerBase
virtual	~MTDClusterizerBase ()

Static Public Member Functions
static void	fillDescriptions (edm::ParameterSetDescription &desc)

Private Member Functions
void	clear_buffer (RecHitIterator itr)
	Clear the internal buffer array. More...
void	copy_to_buffer (RecHitIterator itr)
	Copy FTLRecHit into the buffer, identify seeds. More...
FTLCluster	make_cluster (const FTLCluster::FTLHitPos &hit)
	The actual clustering algorithm: group the neighboring hits around the seed. More...
bool	setup (const MTDGeometry *geometry, const MTDTopology *topo, const DetId &id)

Private Attributes
bool	bufferAlreadySet
MTDArrayBuffer	theBuffer
	Data storage. More...
std::vector< FTLCluster >	theClusters
float	theClusterThreshold
DetId	theCurrentId
float	theHitThreshold
	Clustering-related quantities: More...
int	theNumOfCols
int	theNumOfRows
	Geometry-related information. More...
std::vector< FTLCluster::FTLHitPos >	theSeeds
float	theSeedThreshold
float	theTimeThreshold

Additional Inherited Members
Public Types inherited from MTDClusterizerBase
typedef FTLClusterCollection::const_iterator	ClusterIterator
typedef FTLRecHitCollection::const_iterator	RecHitIterator

Detailed Description

An explicit threshold-based clustering algorithm.

A threshold-based clustering algorithm which clusters FTLRecHits into FTLClusters for each DetUnit. The algorithm is straightforward and purely topological: the clustering process starts with seed hits and continues by adding adjacent hits above the hit threshold. Once the cluster is made, it has to be above the cluster threshold as well.

The clusterization is performed on a matrix with size equal to the size of the MTD detector, each cell containing the cahrge and time of the corresponding hit The matrix is reset after each clusterization.

The search starts from seed hits, i.e. hits with sufficiently large amplitudes

FTLCluster contains a barycenter, but it should be noted that that information is largely useless. One must use a PositionEstimator class to compute the RecHit position and its error for every given cluster.

Sets the MTDArrayBuffer dimensions and pixel thresholds. Makes clusters and stores them in theCache if the option useCache has been set.

Definition at line 51 of file MTDThresholdClusterizer.h.

Constructor & Destructor Documentation

MTDThresholdClusterizer::MTDThresholdClusterizer

(

edm::ParameterSet const &

conf

)

Constructor:

Definition at line 29 of file MTDThresholdClusterizer.cc.

                                :
    // Get energy thresholds 
    theHitThreshold( conf.getParameter<double>("HitThreshold") ),
    theSeedThreshold( conf.getParameter<double>("SeedThreshold") ),
    theClusterThreshold( conf.getParameter<double>("ClusterThreshold") ),
    theTimeThreshold( conf.getParameter<double>("TimeThreshold") ),
    theNumOfRows(0), theNumOfCols(0), theCurrentId(0), 
    theBuffer(theNumOfRows, theNumOfCols ),
    bufferAlreadySet(false)
{
}

MTDThresholdClusterizer::~MTDThresholdClusterizer ( )

override

Definition at line 41 of file MTDThresholdClusterizer.cc.

{}

Member Function Documentation

void MTDThresholdClusterizer::clear_buffer ( RecHitIterator  itr )

private

Clear the internal buffer array.

MTDs which are not part of recognized clusters are NOT ERASED during the cluster finding. Erase them now.

Definition at line 211 of file MTDThresholdClusterizer.cc.

{
  theBuffer.clear( itr->row(), itr->column() ); 
}

void MTDThresholdClusterizer::clusterize ( const FTLRecHitCollection &  input, const MTDGeometry *  geom, const MTDTopology *  topo, FTLClusterCollection &  output  )

overridevirtual

Cluster hits. This method operates on a matrix of hits and finds the largest contiguous cluster around each seed hit. Input and output data stored in DetSet.

Implements MTDClusterizerBase.

Definition at line 98 of file MTDThresholdClusterizer.cc.

References begin, edm::SortedCollection< T, SORT >::begin(), MTDDetId::BTL, DEBUG, TauDecayModes::dec, edmNew::DetSetVector< T >::empty(), end, edm::SortedCollection< T, SORT >::end(), FTLCluster::energy(), MTDDetId::ETL, Exception, MTDDetId::FastTime, MTDTopology::getMTDTopologyMode(), mps_fire::i, MTDDetId::mtdSubDetector(), edmNew::DetSetVector< T >::FastFiller::push_back(), DetId::rawId(), GeneralSetup::setup(), edm::SortedCollection< T, SORT >::size(), FTLCluster::size(), MTDDetId::subDetector(), FTLCluster::time(), FTLCluster::x(), and FTLCluster::y().

                                                    {
  
  FTLRecHitCollection::const_iterator begin = input.begin();
  FTLRecHitCollection::const_iterator end   = input.end();
  
  // Do not bother for empty detectors
  if (begin == end) 
    {
      edm::LogInfo("MTDThresholdClusterizer") << "No hits to clusterize";
      return;
    }

  DEBUG("Input collection " << input.size());
  assert(output.empty());

  std::set<unsigned> geoIds; 
  std::multimap<unsigned, unsigned> geoIdToIdx;
  
  unsigned index = 0;
  for(const auto& hit : input) 
    {
      MTDDetId mtdId=MTDDetId(hit.detid());
      if (mtdId.subDetector() != MTDDetId::FastTime)
    {
      throw cms::Exception("MTDThresholdClusterizer") << "MTDDetId: " << std::hex
                              << mtdId.rawId()
                              << " is invalid!" << std::dec
                              << std::endl;
    }

      if ( mtdId.mtdSubDetector() == MTDDetId::BTL )
    {
      BTLDetId hitId(hit.detid());
      DetId geoId = hitId.geographicalId( (BTLDetId::CrysLayout) topo->getMTDTopologyMode() ); //for BTL topology gives different layout id
      geoIdToIdx.emplace(geoId,index);
      geoIds.emplace(geoId);
      ++index;
    }
      else if ( mtdId.mtdSubDetector() == MTDDetId::ETL )
    {
      ETLDetId hitId(hit.detid());
      DetId geoId = hitId.geographicalId();
      geoIdToIdx.emplace(geoId,index);
      geoIds.emplace(geoId);
      ++index;
    }
      else
    {
      throw cms::Exception("MTDThresholdClusterizer") << "MTDDetId: " << std::hex
                              << mtdId.rawId()
                              << " is invalid!" << std::dec
                              << std::endl;
    }
    }

  //cluster hits within geoIds (modules)
  for(unsigned id : geoIds) {
    //  Set up the clusterization on this DetId.
    if ( !setup(geom,topo,DetId(id)) ) 
      return;
    
    auto range = geoIdToIdx.equal_range(id);
    DEBUG("Matching Ids for " << std::hex << id << std::dec << " [" <<  range.first->second << "," << range.second->second << "]");
    
    //  Copy MTDRecHits to the buffer array; select the seed hits
    //  on the way, and store them in theSeeds.
    for(auto itr = range.first; itr != range.second; ++itr) {
      const unsigned hitidx = itr->second;
      copy_to_buffer(begin+hitidx);
    }
    
    FTLClusterCollection::FastFiller clustersOnDet(output,id);

    for (unsigned int i = 0; i < theSeeds.size(); i++) 
      {
    if ( theBuffer.energy(theSeeds[i]) > theSeedThreshold ) 
      {  // Is this seed still valid?
        //  Make a cluster around this seed
        const FTLCluster & cluster = make_cluster( theSeeds[i] );
        
        //  Check if the cluster is above threshold  
        if ( cluster.energy() > theClusterThreshold) 
          {
        DEBUG("putting in this cluster " << i << " #hits:" << cluster.size() 
              << " E:" << cluster.energy() 
              << " T:" << cluster.time() 
              << " X:" << cluster.x() 
              << " Y:" << cluster.y());
        clustersOnDet.push_back( cluster ); 
          }
      }
      }
  
    // Erase the seeds.
    theSeeds.clear();  
    //  Need to clean unused hits from the buffer array.
    for(auto itr = range.first; itr != range.second; ++itr) {
      const unsigned hitidx = itr->second;
      clear_buffer(begin+hitidx);
    }
  }
}

void MTDThresholdClusterizer::copy_to_buffer ( RecHitIterator  itr )

private

Copy FTLRecHit into the buffer, identify seeds.

Definition at line 219 of file MTDThresholdClusterizer.cc.

References cuy::col, DEBUG, and protons_cff::time.

{
    int row = itr->row();
    int col = itr->column();
    float energy = itr->energy();
    float time = itr->time();
    float timeError = itr->timeError();

    DEBUG("ROW " <<  row << " COL " << col << " ENERGY " << energy << " TIME " << time);
    if ( energy > theHitThreshold) {
      theBuffer.set( row, col, energy , time, timeError); 
      if ( energy > theSeedThreshold) theSeeds.push_back( FTLCluster::FTLHitPos(row,col));
      //sort seeds?
    }
}

void MTDThresholdClusterizer::fillDescriptions ( edm::ParameterSetDescription &  desc )

static

Definition at line 46 of file MTDThresholdClusterizer.cc.

References edm::ParameterSetDescription::add().

Referenced by MTDClusterProducer::fillDescriptions().

                                                                          {
  desc.add<double>("HitThreshold", 0.);
  desc.add<double>("SeedThreshold", 0.);
  desc.add<double>("ClusterThreshold", 0.);
  desc.add<double>("TimeThreshold", 10.);
}

FTLCluster MTDThresholdClusterizer::make_cluster ( const FTLCluster::FTLHitPos &  hit )

private

The actual clustering algorithm: group the neighboring hits around the seed.

Definition at line 240 of file MTDThresholdClusterizer.cc.

References funct::abs(), MTDClusterizerBase::AccretionCluster::add(), EnergyCorrector::c, FTLCluster::FTLHitPos::col(), MTDClusterizerBase::AccretionCluster::empty(), MTDClusterizerBase::AccretionCluster::energy, FTLCluster::energy(), MTDClusterizerBase::AccretionCluster::isize, SiStripPI::max, min(), MTDClusterizerBase::AccretionCluster::pop(), alignCSCRings::r, FTLCluster::FTLHitPos::row(), mathSSE::sqrt(), MTDClusterizerBase::AccretionCluster::time, MTDClusterizerBase::AccretionCluster::timeError, MTDClusterizerBase::AccretionCluster::top(), MTDClusterizerBase::AccretionCluster::x, MTDClusterizerBase::AccretionCluster::xmin, MTDClusterizerBase::AccretionCluster::y, and MTDClusterizerBase::AccretionCluster::ymin.

{
  
  //First we acquire the seeds for the clusters
  float seed_energy= theBuffer.energy(hit.row(), hit.col());
  float seed_time= theBuffer.time(hit.row(), hit.col());
  float seed_time_error= theBuffer.time_error(hit.row(), hit.col());
  theBuffer.clear(hit);
  
  AccretionCluster acluster;
  acluster.add(hit, seed_energy, seed_time, seed_time_error);
  
  bool stopClus=false;
  //Here we search all hits adjacent to all hits in the cluster.
  while ( ! acluster.empty() && ! stopClus) 
    {
      //This is the standard algorithm to find and add a hit
      auto curInd = acluster.top(); acluster.pop();
      for ( auto c = std::max(0,int(acluster.y[curInd]-1)); c < std::min(int(acluster.y[curInd]+2),int(theBuffer.columns())) && !stopClus; ++c) {
      for ( auto r = std::max(0,int(acluster.x[curInd]-1)); r < std::min(int(acluster.x[curInd]+2),int(theBuffer.rows()))  && !stopClus; ++r)  {
      if ( theBuffer.energy(r,c) > theHitThreshold) {
        if (std::abs(theBuffer.time(r,c) - seed_time) > theTimeThreshold*sqrt( theBuffer.time_error(r,c)*theBuffer.time_error(r,c) + seed_time_error*seed_time_error))
          continue;
        FTLCluster::FTLHitPos newhit(r,c);
        if (!acluster.add( newhit, theBuffer.energy(r,c), theBuffer.time(r,c), theBuffer.time_error(r,c))) 
          {
        stopClus=true;
        break;
          }
        theBuffer.clear(newhit);
      }
    }
      }
    }  // while accretion
  
  FTLCluster cluster( theCurrentId, acluster.isize, 
              acluster.energy.data(), acluster.time.data(), acluster.timeError.data(), 
              acluster.x.data(), acluster.y.data(), 
              acluster.xmin, acluster.ymin);
  return cluster;
}

bool MTDThresholdClusterizer::setup ( const MTDGeometry *  geom, const MTDTopology *  topo, const DetId &  id  )

private

Prepare the Clusterizer to work on a particular DetUnit. Re-init the size of the panel/plaquette (so update nrows and ncols),

Definition at line 57 of file MTDThresholdClusterizer.cc.

References DEBUG, TauDecayModes::dec, Exception, triggerObjects_cff::id, MTDGeometry::idToDet(), hgcalPlots::ncols, RectangularMTDTopology::ncolumns(), RectangularMTDTopology::nrows(), and ProxyMTDTopology::specificTopology().

{
  theCurrentId=id;
  //using geopraphicalId here
  const auto& thedet = geom->idToDet(id);
  if( thedet == nullptr ) {
    throw cms::Exception("MTDThresholdClusterizer") << "GeographicalID: " << std::hex
                            << id.rawId()
                            << " is invalid!" << std::dec
                            << std::endl;
    return false;
  }
  const ProxyMTDTopology& topoproxy = static_cast<const ProxyMTDTopology&>(thedet->topology());
  const RectangularMTDTopology& topol = static_cast<const RectangularMTDTopology&>(topoproxy.specificTopology());    
  
  // Get the new sizes.
  unsigned int nrows = topol.nrows();      // rows in x
  unsigned int ncols = topol.ncolumns();   // cols in y
  
  theNumOfRows = nrows;  // Set new sizes
  theNumOfCols = ncols;
  
  DEBUG("Buffer size [" << theNumOfRows+1 << "," << theNumOfCols+1 << "]");
  
  if ( nrows > theBuffer.rows() || 
       ncols > theBuffer.columns() ) 
    { // change only when a larger is needed
      // Resize the buffer
      theBuffer.setSize(nrows+1,ncols+1);  // +1 needed for MTD
      bufferAlreadySet = true;
    }
  
  return true;   
}

Member Data Documentation

bool MTDThresholdClusterizer::bufferAlreadySet

private

Definition at line 84 of file MTDThresholdClusterizer.h.

MTDArrayBuffer MTDThresholdClusterizer::theBuffer

private

Data storage.

Definition at line 83 of file MTDThresholdClusterizer.h.

std::vector<FTLCluster> MTDThresholdClusterizer::theClusters

private

Definition at line 68 of file MTDThresholdClusterizer.h.

float MTDThresholdClusterizer::theClusterThreshold

private

Definition at line 73 of file MTDThresholdClusterizer.h.

DetId MTDThresholdClusterizer::theCurrentId

private

Definition at line 80 of file MTDThresholdClusterizer.h.

float MTDThresholdClusterizer::theHitThreshold

private

Clustering-related quantities:

Definition at line 71 of file MTDThresholdClusterizer.h.

int MTDThresholdClusterizer::theNumOfCols

private

Definition at line 78 of file MTDThresholdClusterizer.h.

int MTDThresholdClusterizer::theNumOfRows

private

Geometry-related information.

Definition at line 77 of file MTDThresholdClusterizer.h.

std::vector<FTLCluster::FTLHitPos> MTDThresholdClusterizer::theSeeds

private

Definition at line 67 of file MTDThresholdClusterizer.h.

float MTDThresholdClusterizer::theSeedThreshold

private

Definition at line 72 of file MTDThresholdClusterizer.h.

float MTDThresholdClusterizer::theTimeThreshold

private

Definition at line 74 of file MTDThresholdClusterizer.h.