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#include <TrimmedVertexFinder.h>
Algorithm to find 0 or 1 cluster of tracks that are compatible with a single vertex, among `remain`, the initial set of tracks. A track is declared incompatible with the vertex if the chi-squared probability between the track and the vertex is smaller than `min`. The algorithm applied is:
1) fit a single vertex with all tracks;
2) remove incompatible tracks 1 by 1 starting from the least compatible one.
On output, `remain` contains the incompatible tracks. This algorithm has 1 parameter that can be set at runtime via the corresponding set() method:
Definition at line 28 of file TrimmedVertexFinder.h.
| typedef ReferenceCountingPointer<LinearizedTrackState<5> > TrimmedVertexFinder::RefCountedLinearizedTrackState |
Definition at line 33 of file TrimmedVertexFinder.h.
Definition at line 32 of file TrimmedVertexFinder.h.
| TrimmedVertexFinder::TrimmedVertexFinder | ( | const VertexFitter< 5 > * | vf, |
| const VertexUpdator< 5 > * | vu, | ||
| const VertexTrackCompatibilityEstimator< 5 > * | ve | ||
| ) |
Definition at line 9 of file TrimmedVertexFinder.cc.
Referenced by clone().
: theFitter(vf->clone()), theUpdator(vu->clone()), theEstimator(ve->clone()), theMinProb(0.05) {}
| TrimmedVertexFinder::TrimmedVertexFinder | ( | const TrimmedVertexFinder & | other | ) |
Copy constructor, needed to handle copy of pointer data members correctly
Definition at line 17 of file TrimmedVertexFinder.cc.
: theFitter(other.theFitter->clone()), theUpdator(other.theUpdator->clone()), theEstimator(other.theEstimator->clone()), theMinProb(other.theMinProb) {}
| TrimmedVertexFinder::~TrimmedVertexFinder | ( | ) |
Definition at line 26 of file TrimmedVertexFinder.cc.
References theEstimator, theFitter, and theUpdator.
{
delete theFitter;
delete theUpdator;
delete theEstimator;
}
| TrimmedVertexFinder* TrimmedVertexFinder::clone | ( | void | ) | const [inline] |
clone method
Definition at line 68 of file TrimmedVertexFinder.h.
References TrimmedVertexFinder().
{
return new TrimmedVertexFinder(*this);
}
| void TrimmedVertexFinder::setTrackCompatibilityCut | ( | float | cut | ) | [inline] |
Set parameter
Definition at line 64 of file TrimmedVertexFinder.h.
References align_tpl::cut, and theMinProb.
Referenced by ConfigurableTrimmedVertexFinder::vertexCandidates().
{ theMinProb = cut; }
| std::vector< TrimmedVertexFinder::RefCountedVertexTrack >::iterator TrimmedVertexFinder::theWorst | ( | const CachingVertex< 5 > & | vtx, |
| std::vector< RefCountedVertexTrack > & | vtxTracks, | ||
| float | cut | ||
| ) | const [private] |
Definition at line 153 of file TrimmedVertexFinder.cc.
References ChiSquaredProbability(), VertexTrackCompatibilityEstimator< N >::estimate(), CachingVertex< N >::isValid(), VertexUpdator< N >::remove(), query::result, theEstimator, theUpdator, and CachingVertex< N >::tracks().
Referenced by vertices().
{
// cout << "Cut is now " << cut << endl;
// find track with worst compatibility
std::vector<RefCountedVertexTrack>::iterator iWorst = vtxTracks.end();
float worseChi2 = 0.;
for (std::vector<RefCountedVertexTrack>::iterator itr = vtxTracks.begin();
itr != vtxTracks.end(); itr++) {
CachingVertex<5> newV = theUpdator->remove(vtx, *itr);
if (!newV.isValid()) return itr;
std::pair<bool, double> result = theEstimator->estimate(newV, *itr);
if (!result.first) return itr;
float chi2 = result.second;
// compute number of degrees of freedom
if ( chi2 > 0. ) {
// we want to keep negative chi squares, and avoid calling
// ChiSquaredProbability with a negative chi2.
int ndf = 2;
if (vtx.tracks().size() == 2) ndf = 1;
float prob = ChiSquaredProbability(chi2, ndf);
if (prob < cut && chi2 >= worseChi2) {
// small inconsistency: sorting on chi2, not on chi2 probability
// because large chi2 are not rounded off while small probabilities
// are rounded off to 0....
// should not matter since at a given iteration
// all track chi2 increments have the same ndf
iWorst = itr;
worseChi2 = chi2;
}
}
}
return iWorst;
}
| float TrimmedVertexFinder::trackCompatibilityCut | ( | ) | const [inline] |
Access to parameter
Definition at line 60 of file TrimmedVertexFinder.h.
References theMinProb.
{ return theMinProb; }
| std::vector< TransientVertex > TrimmedVertexFinder::vertices | ( | std::vector< reco::TransientTrack > & | remain | ) | const |
Make 0 or 1 vertex On output, `remain` contains the incompatible tracks
Definition at line 33 of file TrimmedVertexFinder.cc.
Referenced by ConfigurableTrimmedVertexFinder::vertexCandidates().
{
// FIXME write this!!!
return vertices ( tks, reco::BeamSpot(), false );
}
| std::vector< TransientVertex > TrimmedVertexFinder::vertices | ( | std::vector< reco::TransientTrack > & | remain, |
| const reco::BeamSpot & | s, | ||
| bool | use_beamspot = true |
||
| ) | const |
Same as above, only with the extra information of the beamspot constraint.
Definition at line 40 of file TrimmedVertexFinder.cc.
References cond::ecalcond::all, Exception, newFWLiteAna::found, i, CachingVertex< N >::isValid(), matplotRender::t, theFitter, theMinProb, theWorst(), PerigeeLinearizedTrackState::track(), CachingVertex< N >::tracks(), and VertexFitter< N >::vertex().
{
std::vector<TransientVertex> all;
if (tks.size() < 2) return all;
// prepare vertex tracks and initial vertex
CachingVertex<5> vtx;
if ( use_spot )
{
vtx = theFitter->vertex(tks, spot );
} else {
vtx = theFitter->vertex(tks);
}
if (!vtx.isValid()) {
edm::LogWarning ( "TrimmedVertexFinder" ) << "initial vertex invalid."
<< " vertex finding stops here.";
return all;
}
std::vector<RefCountedVertexTrack> selected = vtx.tracks();
// reject incompatible tracks starting from the worst
std::vector<RefCountedVertexTrack> remain;
bool found = false;
while (!found && selected.size() >= 2) {
// find track with worst compatibility
std::vector<RefCountedVertexTrack>::iterator iWorst = theWorst(vtx,
selected,
theMinProb);
if (iWorst != selected.end()) {
// reject track
remain.push_back(*iWorst);
selected.erase(iWorst);
if (selected.size() == 1) {
// not enough tracks to build new vertices
remain.push_back(selected.front());
}
else {
// removing track from vertex
// need to redo the vertex fit instead of removing the track;
// successive removals lead to numerical problems
// this is however quick since intermediate quantities are cached
// in the RefCountedVertexTracks
if ( use_spot ) // && all.size()==0 )
{
vtx = theFitter->vertex(selected,spot);
} else {
vtx = theFitter->vertex(selected);
}
if (!vtx.isValid()) {
edm::LogWarning ( "TrimmedVertexFinder" ) << "current vertex invalid"
<< "vertex finding stops here.";
return all;
}
// ref-counted tracks may have changed during the fit
// if the linearization point has moved too much
selected = vtx.tracks();
}
} else {
// no incompatible track remains, make vertex
found = true;
int n_tracks_in_vertex = selected.size();
// now return all tracks with weight < 0.5 to 'remain'.
for ( std::vector< RefCountedVertexTrack >::const_iterator t=selected.begin();
t!=selected.end() ; ++t )
{
if ( (**t).weight() < 0.5 )
{
/*
cout << "[TrimmedVertexFinder] recycling track with weight "
<< (**t).weight() << endl;*/
remain.push_back ( *t );
n_tracks_in_vertex--; // one 'good' track less in the vertex
};
};
if ( n_tracks_in_vertex > 1 ) {
all.push_back(vtx);
}
else {
edm::LogError ( "TrimmedVertexFinder" )
<< "found vertex has less than 2 tracks";
}
}
}
// modify list of incompatible tracks
tks.clear();
for (std::vector<RefCountedVertexTrack>::const_iterator i = remain.begin();
i != remain.end(); i++) {
const PerigeeLinearizedTrackState* plts =
dynamic_cast<const PerigeeLinearizedTrackState*>
((**i).linearizedTrack().get());
if (plts == 0) {
throw cms::Exception("TrimmedVertexFinder: can't take track from non-perigee track state");
}
tks.push_back(plts->track());
}
// return 0 or 1 vertex
return all;
}
Definition at line 85 of file TrimmedVertexFinder.h.
Referenced by theWorst(), and ~TrimmedVertexFinder().
VertexFitter<5>* TrimmedVertexFinder::theFitter [private] |
Definition at line 83 of file TrimmedVertexFinder.h.
Referenced by vertices(), and ~TrimmedVertexFinder().
float TrimmedVertexFinder::theMinProb [private] |
Definition at line 86 of file TrimmedVertexFinder.h.
Referenced by setTrackCompatibilityCut(), trackCompatibilityCut(), and vertices().
VertexUpdator<5>* TrimmedVertexFinder::theUpdator [private] |
Definition at line 84 of file TrimmedVertexFinder.h.
Referenced by theWorst(), and ~TrimmedVertexFinder().
1.7.3