ISF::GeoIDSvc Class Reference

A fast Athena service identifying the AtlasRegion a given position/particle is in. More...

#include <GeoIDSvc.h>

Inheritance diagram for ISF::GeoIDSvc:

Collaboration diagram for ISF::GeoIDSvc:

Public Member Functions
	GeoIDSvc (const std::string &name, ISvcLocator *svc)
	Constructor with parameters.
	~GeoIDSvc ()=default
	Destructor.
StatusCode	initialize ()
AtlasDetDescr::AtlasRegion	identifyGeoID (const Amg::Vector3D &pos) const
	A static filter that returns the SimGeoID of the given position.
ISF::InsideType	inside (const Amg::Vector3D &pos, AtlasDetDescr::AtlasRegion geoID) const
	Checks if the given position (or ISFParticle) is inside a given SimGeoID.
AtlasDetDescr::AtlasRegion	identifyNextGeoID (const Amg::Vector3D &pos, const Amg::Vector3D &dir) const
	Find the SimGeoID that the particle will enter with its next infinitesimal step along the given direction.

Private Member Functions
std::unique_ptr< RZPairList >	prepareRZPairs (AtlasDetDescr::AtlasRegion geoID)
bool	checkSymmetric (RZPairList &positiveZ, RZPairList &negativeZ)
	Check if given RZPairLists are symmetric around z==0 plane.
template<typename T>
int	sign (T val)
	a branchless signum function

Private Attributes
ServiceHandle< IEnvelopeDefSvc >	m_envDefSvc
	service providing the envelope dimensions for the different sub-detectors
DoubleProperty	m_tolerance
	(estimated) tolerance within which coordinates are considered equal
double *	m_zBins {}
int	m_numZBins {0}
RadiusGeoIDPair *	m_radiusBins {}
	m_radiusBins[m_numZBins][numCurRadiusBins]
int	m_maxRBins {AtlasDetDescr::fNumAtlasRegions+1}

Detailed Description

A fast Athena service identifying the AtlasRegion a given position/particle is in.

Author

Elmar.Ritsch -at- cern.ch

Definition at line 43 of file GeoIDSvc.h.

Constructor & Destructor Documentation

GeoIDSvc()

ISF::GeoIDSvc::GeoIDSvc	(	const std::string &	name,
		ISvcLocator *	svc )

Constructor with parameters.

Constructor.

Definition at line 19 of file GeoIDSvc.cxx.

                                                            :
  base_class(name,svc)
{
}

~GeoIDSvc()

ISF::GeoIDSvc::~GeoIDSvc ( )

default

Destructor.

Member Function Documentation

checkSymmetric()

bool ISF::GeoIDSvc::checkSymmetric ( RZPairList & positiveZ, RZPairList & negativeZ )

private

Check if given RZPairLists are symmetric around z==0 plane.

Definition at line 391 of file GeoIDSvc.cxx.

                                                                              {
  ATH_MSG_DEBUG("checking symmetry around z==0 plane for given (r,z) pairs");
 
  // require same size
  if ( positiveZ.size() != negativeZ.size()) {
    ATH_MSG_ERROR("Can not interpret the (r,z) pairs given by the EnvelopeDefSvc");
    ATH_MSG_ERROR("  -> different number of (r,z) pairs on either side of the z==0 plane");
    return false;
  }
 
  // some debug output
  //if ( msgLevel(MSG::VERBOSE)) {
  //  ATH_MSG_VERBOSE("(r,z) pairs on positive z side");
  //  RZPairList::iterator it    = positiveZ.begin();
  //  RZPairList::iterator itEnd = positiveZ.end();
  //  for ( ; it!=itEnd; it++) ATH_MSG_VERBOSE(" r=" << it->first << " z=" << it->second);
  //  ATH_MSG_VERBOSE("(r,z) pairs on negative z side");
  //  it    = negativeZ.begin();
  //  itEnd = negativeZ.end();
  //  for ( ; it!=itEnd; it++) ATH_MSG_VERBOSE(" r=" << it->first << " z=" << it->second);
  //}
 
  // iterate over lists to compare (r,z) value pairs
  RZPairList::iterator posIt      = positiveZ.begin();
  RZPairList::iterator posItEnd   = positiveZ.end();
  //RZPairList::iterator negItBegin = negativeZ.begin();
  RZPairList::iterator negIt      = negativeZ.end();
 
  while ( posIt != posItEnd) {
    --negIt;
 
    // require that deltaR and deltaZ are the same within bounds
    if ( fabs(negIt->first-posIt->first)>m_tolerance || fabs(negIt->second+posIt->second)>m_tolerance)
      return false;
 
    ++posIt;
  }
 
  // all fine
  return true;
}

identifyGeoID()

AtlasDetDescr::AtlasRegion ISF::GeoIDSvc::identifyGeoID

(

const Amg::Vector3D &

pos

)

const

A static filter that returns the SimGeoID of the given position.

Definition at line 222 of file GeoIDSvc.cxx.

                                                                                {
 
  // (1.) resolve z-bin number for the given z coordinate
  // TODO: test if maybe a binary search is faster than
  //       this linear search
  int zBin = 0;
  double z = fabs(pos.z()) ;
  while ( (zBin<m_numZBins) && (z>=m_zBins[zBin]) ) {
    zBin++;
  }
  //ATH_MSG_VERBOSE(" zBin=" << zBin << " (z<"<<m_zBins[zBin]<<")");
 
  // (2.) use zBin to resolve the geoID via the m_radiusBins 2d-array
  // TODO: test if maybe a binary search is faster than
  //       this linear search
  int radiusBin = 0;
  double r2 = pos.perp2();
  while ( (m_radiusBins[zBin*m_maxRBins+radiusBin].second!=AtlasDetDescr::fUndefinedAtlasRegion) &&
          (r2 >= m_radiusBins[zBin*m_maxRBins+radiusBin].first) ) {
    radiusBin++;
  }
  //ATH_MSG_VERBOSE(" radiusBin=" << radiusBin <<
  //                " (r<"<< sqrt(m_radiusBins[zBin*m_maxRBins+radiusBin].first)<<")");
  //ATH_MSG_VERBOSE("  --> geoID=" << m_radiusBins[zBin*m_maxRBins+radiusBin].second);
 
  // is AtlasDetDescr::fUndefinedAtlasRegion in case not found
  AtlasDetDescr::AtlasRegion identifiedGeoID = m_radiusBins[zBin*m_maxRBins+radiusBin].second;
  return identifiedGeoID;
}

identifyNextGeoID()

AtlasDetDescr::AtlasRegion ISF::GeoIDSvc::identifyNextGeoID	(	const Amg::Vector3D &	pos,
		const Amg::Vector3D &	dir ) const

Find the SimGeoID that the particle will enter with its next infinitesimal step along the given direction.

Definition at line 254 of file GeoIDSvc.cxx.

                                                                                          {
 
  // push the particle a little and check the volume it's in
  AtlasDetDescr::AtlasRegion geoID = identifyGeoID( pos + dir.unit()*m_tolerance );
 
  // alternatively: before push-ing check the current position
  //AtlasDetDescr::AtlasRegion geoID = identifyGeoID( pos);
  //if (geoID == AtlasDetDescr::fUndefinedAtlasRegion) {
  //  const HepGeom::Vector3D<double> &posStep = pos + dir.unit();
  //  geoID = identifyGeoID( posStep);
  //}
 
  return geoID;
}

initialize()

StatusCode ISF::GeoIDSvc::initialize

(

)

Definition at line 25 of file GeoIDSvc.cxx.

{
  ATH_MSG_DEBUG("initialize() ...");
 
  // retrieve envelope definition service
  ATH_CHECK(m_envDefSvc.retrieve());
 
  // create internal volume representations for the given dimensions
  std::vector<double>                      tmpZBins[AtlasDetDescr::fNumAtlasRegions];
  std::map< size_t, double >               tmpRBins[AtlasDetDescr::fNumAtlasRegions];
  //std::map< size_t, std::array<RadiusGeoIDPair,2> > tmpRBins[AtlasDetDescr::fNumAtlasRegions];
 
  for (int geoID=AtlasDetDescr::fFirstAtlasRegion; geoID<AtlasDetDescr::fNumAtlasRegions; ++geoID) {
 
    // retrieve a list of (r,z) pairs for the z>0
    // side of the envelope
    std::unique_ptr<RZPairList> curRZ = prepareRZPairs( AtlasDetDescr::AtlasRegion(geoID) );
    if (curRZ->size()==0) {
      ATH_MSG_ERROR("Unable to create volume representation for geoID="<<geoID);
      return StatusCode::FAILURE;
    }
    ATH_MSG_VERBOSE("Found " << curRZ->size() << " (r,z) pairs with positive z for geoID=" << geoID);
 
    // TODO:
    // make sure the list of (r,z) pairs is supported by this GeoIDSvc implementation
    //   -> only cylindrical boundaries, no conical boundaries
    //   -> no undercuts
    //if ( checkRZPairs(curRZ).isFailure()) {
    //  ATH_MSG_ERROR("Unable to create volume representation for geoID="<<geoID);
    //  return StatusCode::FAILURE;
    //}
 
    ATH_MSG_DEBUG("Preparing " << curRZ->size() << " (r,z) pairs with positive z for geoID=" << geoID);
    while ( curRZ->size()) {
      //double minR = std::min( curRZ.front().first , curRZ.back().first );
      double maxR = std::max( curRZ->front().first , curRZ->back().first );
      double zFront = curRZ->front().second;
      double zBack  = curRZ->back().second;
      double minZ = std::min( zFront, zBack);
 
      ATH_MSG_VERBOSE(" minz=" << minZ << " zBack="<<zBack<<" zFront="<<zFront<<" maxR="<<maxR<<" curRZ->size()="<<curRZ->size());
 
      // remove items only on the one side of the list that
      // has the smaller z
      if      (zFront<zBack) curRZ->pop_front();
      else if (zBack<zFront) curRZ->pop_back();
      else {
        // both are equal in z
        curRZ->pop_front();
        if (curRZ->size()>0) curRZ->pop_back();
      }
 
      // register the boundary value of new bin in z
      size_t curZBin = tmpZBins[geoID].size();
      // skip this entry if minZ did not change
      if ( (curZBin>0) && ( fabs(tmpZBins[geoID][curZBin-1]-minZ) <m_tolerance) ) continue;
 
      tmpZBins[geoID].push_back(minZ);
 
      // construct the (radius^2,geoID) pairs
      //std::array<RadiusGeoIDPair, 2> radiusGeoIDs;
      //                radiusGeoIDs[0] = RadiusGeoIDPair(minR*minR, AtlasDetDescr::fUndefinedAtlasRegion);
      //if (curZBin==0) radiusGeoIDs[1] = RadiusGeoIDPair(maxR*maxR, AtlasDetDescr::fUndefinedAtlasRegion);
      //else            radiusGeoIDs[1] = RadiusGeoIDPair(maxR*maxR, AtlasDetDescr::AtlasRegion(geoID));
      //tmpRBins[geoID][curZBin] = radiusGeoIDs;
      tmpRBins[geoID][curZBin] = maxR*maxR;
    }
  } // loop over geoIDs
 
  ATH_MSG_DEBUG("Combining individual volumen boundaries in one common representation");
  // convert and combine the gathered tmpRBins, tmpZBins into
  // tmpZBinsGlobal, tmpRBinsGlobal which will have the same
  // format as the member variables m_zBins and m_radiusBins
  size_t  tmpZBinIndex[AtlasDetDescr::fNumAtlasRegions];
  for (int geoID=AtlasDetDescr::fFirstAtlasRegion; geoID<AtlasDetDescr::fNumAtlasRegions; ++geoID)
    tmpZBinIndex[geoID] = 0;
  std::vector<double>                    tmpZBinsGlobal;
  std::map< size_t, RadiusGeoIDPairSet > tmpRBinsGlobal;
  RadiusGeoIDPairSet curRadiusGeoIDs;
  double  minZ = 1e99;
  double  prevMinZ;
  while (true) {
    AtlasDetDescr::AtlasRegion  minZGeoID = AtlasDetDescr::fUndefinedAtlasRegion;
 
    // loop until a bin with minimum z value is found that
    // differs at least m_tolerance from previous minZ
    do {
      ATH_MSG_VERBOSE(" (re)starting search for minZ");
      prevMinZ = minZ;
      minZ = 1e99;
      curRadiusGeoIDs.clear();
 
      // loop over all geoIDs to find the bin with minimum z
      for (int geoID=AtlasDetDescr::fFirstAtlasRegion; geoID<AtlasDetDescr::fNumAtlasRegions; ++geoID) {
        size_t curTmpZBinIndex = tmpZBinIndex[geoID];
        // ignore the current tmpZBins in case we already reached
        // it's end
        if ( curTmpZBinIndex >= tmpZBins[geoID].size()) continue;
        double curZ = tmpZBins[geoID][curTmpZBinIndex];
        // curZ==0 -> skip this one
        if ( fabs(curZ)<m_tolerance) {
          (tmpZBinIndex[geoID])++;
        }
        // curZ is the smallest z so far
        //   -> register it (minZ, minZGeoID)
        //   -> increment iterator for current tmpZBinIt
        else if ( curZ<minZ) {
          minZ = curZ;
          minZGeoID = AtlasDetDescr::AtlasRegion(geoID);
        }
        double curR2 = tmpRBins[geoID][curTmpZBinIndex];
 
        ATH_MSG_VERBOSE("inserting pair: r="<< sqrt(curR2) <<
                        " geoID=" << geoID << " for minZ<=" << minZ);
        curRadiusGeoIDs.insert( RadiusGeoIDPair(curR2, AtlasDetDescr::AtlasRegion(geoID)) );
      } // geoID loop
      // iterate the tmpZBinIndex for the one geoID giving the smallest z
      (tmpZBinIndex[minZGeoID])++;
    } while ( fabs(minZ-prevMinZ)<m_tolerance );
 
    // nothing more to do, all tmpZBins are read out already
    if ( curRadiusGeoIDs.size()==0) break;
    ATH_MSG_VERBOSE("Current minZ=" << minZ <<
                    " curRadiusGeoIDs.size()=" << curRadiusGeoIDs.size() );
 
    // add the current z bin to the temporary std vector
    size_t curZBinGlobal = tmpZBinsGlobal.size();
    tmpZBinsGlobal.push_back(minZ);
    tmpRBinsGlobal[curZBinGlobal] = curRadiusGeoIDs;
  };
 
  ATH_MSG_DEBUG("Converting volume representation into faster format");
  // finally write the information in tmpZBinsGlobal and tmpRBinsGlobal
  // into the m_zBins and m_radiusBins
  m_numZBins   = tmpZBinsGlobal.size();
  m_zBins      = new double[m_numZBins];
  m_radiusBins = new RadiusGeoIDPair[(m_numZBins+1)*m_maxRBins];
  // loop over m_zBins
  for (int i=0; i<m_numZBins; i++) {
    m_zBins[i] = tmpZBinsGlobal[i];
    ATH_MSG_VERBOSE(" zBin=" << i << " for z<" << m_zBins[i]);
 
    RadiusGeoIDPairSet::iterator radIt    = tmpRBinsGlobal[i].begin();
    RadiusGeoIDPairSet::iterator radItEnd = tmpRBinsGlobal[i].end();
    size_t                       ii = 0;
    for ( ; radIt!=radItEnd; ++radIt) {
      double curR = sqrt((*radIt).first);
      // skip this one if it has radius==0
      if (curR<m_tolerance) continue;
 
      ATH_MSG_VERBOSE("   radius<" << curR <<
                      " --> geoID=" << (*radIt).second);
      m_radiusBins[i*m_maxRBins+ii++] = (*radIt);
    }
    // fill the last radius bin with fUndefinedGeoID
    m_radiusBins[i*m_maxRBins+ii] = RadiusGeoIDPair( 1e99, AtlasDetDescr::fUndefinedAtlasRegion) ;
  };
 
  return StatusCode::SUCCESS;
}

inside()

ISF::InsideType ISF::GeoIDSvc::inside	(	const Amg::Vector3D &	pos,
		AtlasDetDescr::AtlasRegion	geoID ) const

Checks if the given position (or ISFParticle) is inside a given SimGeoID.

Definition at line 189 of file GeoIDSvc.cxx.

                                                                                              {
 
  // an arbitrary unitary direction with +1 in x,y,z
  // (following this direction will cross any AtlasRegion boundary if position is close to it in the first place)
  const Amg::Vector3D dir(1., 1., 1.);
  const Amg::Vector3D dirUnit( dir.unit() );
 
  // create particle positions which are a bit forward and a bit aft of the current position
  const Amg::Vector3D posFwd( pos + dirUnit*m_tolerance );
  const Amg::Vector3D posAft( pos - dirUnit*m_tolerance );
 
  AtlasDetDescr::AtlasRegion geoIDFwd = identifyGeoID(posFwd);
  AtlasDetDescr::AtlasRegion geoIDAft = identifyGeoID(posAft);
 
  // default case: particle is outside given geoID
  ISF::InsideType where = ISF::fOutside;
 
  // only if either the fwd or the aft step is inside the given geoID,
  // inside/surface cases need to be resolved
  if ( (geoID == geoIDFwd) || (geoID == geoIDAft) ) {
    // 1. inside
    if ( geoIDFwd == geoIDAft ) {
      where = ISF::fInside;
      // 2. surface
    } else if ( geoIDFwd != geoIDAft ) {
      where = ISF::fSurface;
    }
  }
 
  return where;
}

prepareRZPairs()

std::unique_ptr< ISF::RZPairList > ISF::GeoIDSvc::prepareRZPairs ( AtlasDetDescr::AtlasRegion geoID )

private

Definition at line 270 of file GeoIDSvc.cxx.

                                                                                        {
  // fill RZPairLists with pairs of only positive z and only negative
  // z values respectively. it is important to keep the pairs ordered
  // in each list
  //
  std::unique_ptr<RZPairList> positiveZ = std::make_unique<RZPairList>();
  std::unique_ptr<RZPairList> negativeZ = std::make_unique<RZPairList>();
 
  // ensure a proper numeric value for geoID
  assert(validAtlasRegion(geoID));
 
  ATH_MSG_INFO( "Building envelope volume for '" << AtlasDetDescr::AtlasRegionHelper::getName(geoID)
                << "' (GeoID="<< geoID << ").");
 
 
  //
  // fill the RZPairLists
  //
  {
    // both RZPairList have to be empty
    if ( positiveZ->size() || negativeZ->size() ) {
      ATH_MSG_ERROR("Can not interpret the (r,z) pairs provided by the EnvelopeDefSvc");
      positiveZ->clear();
      negativeZ->clear();
      return positiveZ;
    }
 
    // retrieve the vector of (r,z) values from the EnvelopeDefSvc
    const RZPairVector &rz = m_envDefSvc->getRZBoundary( geoID );
 
    // used in the loop over the RZPairVector entries
    RZPairList *curRZList{};
    RZPairList::iterator curRZInsertIt;
    int signZChanges = 0;     // count the number of pos/neg transitions in z
    int prevZSign    = sign(rz.at(0).second);
 
    // loop over the (r,z) pairs in the given RZPairVector
    RZPairVector::const_iterator rzIt    = rz.begin();
    RZPairVector::const_iterator rzItEnd = rz.end();
    for (; rzIt!=rzItEnd; ++rzIt) {
      const RZPair &curRZ = *rzIt;
      double   curZ = curRZ.second;
      int  curZSign = sign(curZ);
 
      ATH_MSG_VERBOSE( " signZChanges=" << signZChanges<<
                       " curZSign=" <<curZSign<<
                       " prevZSign=" << prevZSign<<
                       " curZ=" <<curZ <<
                       " curR=" <<curRZ.first );
 
      // select negative RZPairList to fill
      if ( curZSign==-1)     curRZList = negativeZ.get();
      // select positive RZPairList to fill
      else if ( curZSign==1) curRZList = positiveZ.get();
      // ignore 0.
      else {
        ATH_MSG_WARNING("Ignoring an (r,z) pair from the EnvelopeDefSvc with z==0.");
        continue;
      }
 
      // record if the sign has changed
      if ( curZSign != prevZSign) {
        signZChanges++;
        prevZSign = curZSign;
        // note the begin of the curRZList
        // will be used in case the sign has changed twice
        curRZInsertIt = curRZList->begin();
      }
 
      // (#) the z sign changed at max once in this (r,z) list so far
      //  -> this is the simple case since we are filling the
      //     two RZPairLists from the to each
      if ( signZChanges<2 ) {
        curRZList->push_back(curRZ);
      }
 
      // (#) the z sign changed twice in this (r,z) list so far
      //  -> insert the values from the front into the the current
      //     RZPairList
      else if ( signZChanges==2 ) {
        curRZList->insert( curRZInsertIt, curRZ );
      }
 
      // (#) the z sign changed more than twice
      //  -> no implementation yet to handle this freakin' complicated case
      else {
        ATH_MSG_ERROR("Unable to interpret (r,z) pairs for envelope definition provided by the EnvelopeDefSvc" );
        ATH_MSG_ERROR("  -> provided (r,z) pairs traverse the z==0 plane more than twice" );
        positiveZ->clear();
        negativeZ->clear();
        return positiveZ;
      }
    }
  }
 
  //
  // verify that the RZPairLists are symmetric around z==0.
  //
  if ( (!checkSymmetric( *positiveZ, *negativeZ)) ) {
    ATH_MSG_ERROR("(r,z) pairs received from EnvelopeDefSvc are not symmetric around z==0 plane");
    positiveZ->clear();
    negativeZ->clear();
    return positiveZ;
  }
 
  // add the z==0 entries to the RZList for the case of
  // volumes crossing the z==0 plane
  double frontR = positiveZ->front().first;
  double backR  = positiveZ->back().first;
  positiveZ->push_front( RZPair(frontR, 0.) );
  positiveZ->push_back( RZPair(backR , 0.) );
 
  // clear the RZPairList for negative z values
  negativeZ->clear();
 
  // return the RZPairList for positive z values
  return positiveZ;
}

sign()

template<typename T>

int ISF::GeoIDSvc::sign ( T val )

inlineprivate

a branchless signum function

Definition at line 94 of file GeoIDSvc.h.

                                                          {
    return (T(0) < val) - (val < T(0));
  }

Member Data Documentation

m_envDefSvc

ServiceHandle<IEnvelopeDefSvc> ISF::GeoIDSvc::m_envDefSvc

private

Initial value:

{this, "EnvelopeDefSvc", "ISF_ISFEnvelopeDefSvc",
        "The EnvelopeDefinitionService describing the AtlasRegion boundaries."}

service providing the envelope dimensions for the different sub-detectors

Definition at line 74 of file GeoIDSvc.h.

                                              {this, "EnvelopeDefSvc", "ISF_ISFEnvelopeDefSvc",
        "The EnvelopeDefinitionService describing the AtlasRegion boundaries."};

m_maxRBins

int ISF::GeoIDSvc::m_maxRBins {AtlasDetDescr::fNumAtlasRegions+1}

private

Definition at line 86 of file GeoIDSvc.h.

{AtlasDetDescr::fNumAtlasRegions+1};

m_numZBins

int ISF::GeoIDSvc::m_numZBins {0}

private

Definition at line 83 of file GeoIDSvc.h.

{0};

m_radiusBins

RadiusGeoIDPair* ISF::GeoIDSvc::m_radiusBins {}

private

m_radiusBins[m_numZBins][numCurRadiusBins]

Definition at line 85 of file GeoIDSvc.h.

{};

m_tolerance

DoubleProperty ISF::GeoIDSvc::m_tolerance

private

Initial value:

{this,"Tolerance", 1e-5,
        "Estimated tolerance within which coordinates are considered being equal."}

(estimated) tolerance within which coordinates are considered equal

Definition at line 78 of file GeoIDSvc.h.

                              {this,"Tolerance", 1e-5,
        "Estimated tolerance within which coordinates are considered being equal."};

m_zBins

double* ISF::GeoIDSvc::m_zBins {}

private

Definition at line 82 of file GeoIDSvc.h.

{};

---

The documentation for this class was generated from the following files:

• GeoIDSvc.h
• GeoIDSvc.cxx