1 #ifndef ALIVERTEXERTRACKS_H
2 #define ALIVERTEXERTRACKS_H
3 /* Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
4 * See cxx source for full Copyright notice */
7 //-------------------------------------------------------
8 // Class for vertex determination with tracks
10 // Origin: AliITSVertexerTracks
11 // A.Dainese, Padova, andrea.dainese@pd.infn.it
12 // M.Masera, Torino, massimo.masera@to.infn.it
13 // Moved to STEER and adapted to ESD tracks:
14 // F.Prino, Torino, prino@to.infn.it
15 //-------------------------------------------------------
17 /*****************************************************************************
19 * This class determines the vertex of a set of tracks. *
20 * Different algorithms are implemented, see data member fAlgo. *
22 *****************************************************************************/
24 #include <TObjArray.h>
27 #include "AliESDVertex.h"
28 #include "AliExternalTrackParam.h"
33 class AliVertexerTracks : public TObject {
37 AliVertexerTracks(Double_t fieldkG);
38 virtual ~AliVertexerTracks();
40 AliESDVertex* FindPrimaryVertex(const AliESDEvent *esdEvent);
41 AliESDVertex* FindPrimaryVertex(TObjArray *trkArrayOrig,UShort_t *idOrig);
42 AliESDVertex* VertexForSelectedTracks(TObjArray *trkArray,UShort_t *id,
43 Bool_t optUseFitter=kTRUE,
44 Bool_t optPropagate=kTRUE);
45 AliESDVertex* VertexForSelectedESDTracks(TObjArray *trkArray,
46 Bool_t optUseFitter=kTRUE,
47 Bool_t optPropagate=kTRUE);
48 AliESDVertex* RemoveTracksFromVertex(AliESDVertex *inVtx,
49 TObjArray *trkArray,UShort_t *id,
51 void SetConstraintOff() { fConstraint=kFALSE; return; }
52 void SetConstraintOn() { fConstraint=kTRUE; return; }
53 void SetDebug(Int_t optdebug=0) { fDebug=optdebug; return; }
54 void SetDCAcut(Double_t maxdca) { fDCAcut=maxdca; return; }
55 void SetFinderAlgorithm(Int_t opt=1) { fAlgo=opt; return; }
56 void SetITSrefitRequired() { fITSrefit=kTRUE; return; }
57 void SetITSrefitNotRequired() { fITSrefit=kFALSE; return; }
58 void SetMaxd0z0(Double_t maxd0z0=0.5) { fMaxd0z0=maxd0z0; return; }
59 void SetMinITSClusters(Int_t n=5) { fMinITSClusters=n; return; }
60 void SetMinTracks(Int_t n=1) { fMinTracks=n; return; }
61 void SetNSigmad0(Double_t n=3) { fNSigma=n; return; }
62 Double_t GetNSigmad0() const { return fNSigma; }
63 void SetOnlyFitter() { if(!fConstraint) AliFatal("Set constraint first!");
64 fOnlyFitter=kTRUE; return; }
65 void SetSkipTracks(Int_t n,Int_t *skipped);
66 void SetVtxStart(Double_t x=0,Double_t y=0,Double_t z=0)
67 { fNominalPos[0]=x; fNominalPos[1]=y; fNominalPos[2]=z; return; }
68 void SetVtxStartSigma(Double_t sx=3.,Double_t sy=3.,Double_t sz=15.)
69 { fNominalCov[0]=sx*sx; fNominalCov[2]=sy*sy; fNominalCov[5]=sz*sz;
70 fNominalCov[1]=0.; fNominalCov[3]=0.; fNominalCov[4]=0.; return; }
71 void SetVtxStart(AliESDVertex *vtx);
72 static Double_t GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0);
73 static Double_t GetDeterminant3X3(Double_t matr[][3]);
74 static void GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d);
75 static void GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d);
76 static AliESDVertex TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights=0);
77 void SetFieldkG(Double_t field=-999.) { fFieldkG=field; return; }
78 Double_t GetFieldkG() const {
79 if(fFieldkG<-99.) AliFatal("Field value not set");
81 void SetNSigmaForUi00(Double_t n=1.5) { fnSigmaForUi00=n; return; }
82 Double_t GetNSigmaForUi00() const { return fnSigmaForUi00; }
85 void HelixVertexFinder();
86 void OneTrackVertFinder();
87 Int_t PrepareTracks(TObjArray &trkArrayOrig,UShort_t *idOrig,
89 Bool_t TrackToPoint(AliExternalTrackParam *t,
90 TMatrixD &ri,TMatrixD &wWi,
91 Bool_t uUi3by3=kFALSE) const;
92 void VertexFinder(Int_t optUseWeights=0);
94 void StrLinVertexFinderMinDist(Int_t optUseWeights=0);
97 AliESDVertex fVert; // vertex after vertex finder
98 AliESDVertex *fCurrentVertex; // ESD vertex after fitter
99 Double_t fFieldkG; // z component of field (kGauss)
100 Double_t fNominalPos[3]; // initial knowledge on vertex position
101 Double_t fNominalCov[6]; // initial knowledge on vertex position
102 Bool_t fConstraint; // true when "mean vertex" was set in
103 // fNominal ... and must be used in the fit
104 Bool_t fOnlyFitter; // primary with one fitter shot only
105 // (use only with beam constraint)
106 Int_t fMinTracks; // minimum number of tracks
107 Int_t fMinITSClusters; // minimum number of ITS clusters per track
108 TObjArray fTrkArraySel; // array with tracks to be processed
109 UShort_t *fIdSel; // IDs of the tracks (AliESDtrack::GetID())
110 Int_t *fTrksToSkip; // track IDs to be skipped for find and fit
111 Int_t fNTrksToSkip; // number of tracks to be skipped
112 Double_t fDCAcut; // maximum DCA between 2 tracks used for vertex
113 Int_t fAlgo; // option for vertex finding algorythm
114 Double_t fNSigma; // number of sigmas for d0 cut in PrepareTracks()
115 Double_t fMaxd0z0; // value for sqrt(d0d0+z0z0) cut
116 // in PrepareTracks(1) if fConstraint=kFALSE
117 Bool_t fITSrefit; // if kTRUE (default), use only kITSrefit tracks
118 // if kFALSE, use all tracks (also TPC only)
119 Double_t fnSigmaForUi00; // n. sigmas from finder in TrackToPoint
120 Int_t fDebug; //! debug flag - verbose printing if >0
121 // fAlgo=1 (default) finds minimum-distance point among all selected tracks
122 // approximated as straight lines
123 // and uses errors on track parameters as weights
124 // fAlgo=2 finds minimum-distance point among all the selected tracks
125 // approximated as straight lines
126 // fAlgo=3 finds the average point among DCA points of all pairs of tracks
127 // treated as helices
128 // fAlgo=4 finds the average point among DCA points of all pairs of tracks
129 // approximated as straight lines
130 // and uses errors on track parameters as weights
131 // fAlgo=5 finds the average point among DCA points of all pairs of tracks
132 // approximated as straight lines
136 AliVertexerTracks(const AliVertexerTracks & source);
137 AliVertexerTracks & operator=(const AliVertexerTracks & source);
139 ClassDef(AliVertexerTracks,10) // 3D Vertexing with tracks