Vertex fitting using the errors from the vertex finder (Andrea)
[u/mrichter/AliRoot.git] / STEER / AliVertexerTracks.h
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2d57349e 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 */
5
6
7//-------------------------------------------------------
8// Class for vertex determination with ESD tracks
9//
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//-------------------------------------------------------
16
17/*****************************************************************************
18 * *
19 * This class determines the vertex of a set of ESD tracks. *
20 * Different algorithms are implemented, see data member fAlgo. *
21 * *
22 *****************************************************************************/
23
c5e3e5d1 24#include "AliESDVertex.h"
fee9ef0d 25#include "AliESDtrack.h"
ec1be5d5 26#include "AliLog.h"
2d57349e 27
28#include <TObjArray.h>
fee9ef0d 29#include <TMatrixD.h>
2d57349e 30
31class TTree;
2d57349e 32class AliESD;
33
34class AliVertexerTracks : public TObject {
35
36 public:
37 AliVertexerTracks();
dc3719f3 38 AliVertexerTracks(Double_t fieldkG);
2d57349e 39 virtual ~AliVertexerTracks();
40
ec1be5d5 41 AliESDVertex* FindPrimaryVertex(const AliESD *esdEvent);
fee9ef0d 42 AliESDVertex* VertexForSelectedTracks(TTree *trkTree,Bool_t optUseFitter=kTRUE, Bool_t optPropagate=kTRUE);
dc3719f3 43 AliESDVertex* VertexForSelectedTracks(TObjArray *trkArray, Bool_t optUseFitter=kTRUE, Bool_t optPropagate=kTRUE);
fee9ef0d 44 AliESDVertex* RemoveTracksFromVertex(AliESDVertex *inVtx,TTree *trksTree,Float_t *diamondxy);
45 void SetConstraintOff() { fConstraint=kFALSE; return; }
46 void SetConstraintOn() { fConstraint=kTRUE; return; }
47 void SetDebug(Int_t optdebug=0) { fDebug=optdebug; return; }
48 void SetDCAcut(Double_t maxdca) { fDCAcut=maxdca; return; }
49 void SetFinderAlgorithm(Int_t opt=1) { fAlgo=opt; return; }
50 void SetITSRequired() { fITSin=kTRUE; return; }
51 void SetITSrefitRequired() { fITSin=kTRUE;fITSrefit=kTRUE; return; }
50ff0bcd 52 void SetITSNotRequired() { fITSrefit=kFALSE;fITSin=kFALSE; return; }
53 void SetITSrefitNotRequired() { fITSrefit=kFALSE; return; }
fee9ef0d 54 void SetMaxd0z0(Double_t maxd0z0=0.5) { fMaxd0z0=maxd0z0; return; }
07680cae 55 void SetMinITSClusters(Int_t n=5) { fMinITSClusters = n; return; }
fee9ef0d 56 void SetMinTracks(Int_t n=1) { fMinTracks = n; return; }
57 void SetNSigmad0(Double_t n=3) { fNSigma=n; return; }
58 Double_t GetNSigmad0() const { return fNSigma; }
59 void SetOnlyFitter() { if(!fConstraint) AliFatal("Set constraint first!");
60 fOnlyFitter=kTRUE; return; }
ec1be5d5 61 void SetSkipTracks(Int_t n,Int_t *skipped);
0bf2e2b4 62 void SetVtxStartPos(Double_t x=0,Double_t y=0,Double_t z=0)
07680cae 63 { fNominalPos[0]=x; fNominalPos[1]=y; fNominalPos[2]=z; return; }
146c29df 64 void SetVtxStartSigma(Double_t sx=3.,Double_t sy=3.,Double_t sz=15.)
50ff0bcd 65 { fNominalCov[0]=sx*sx; fNominalCov[2]=sy*sy; fNominalCov[5]=sz*sz;
66 fNominalCov[1]=0.; fNominalCov[3]=0.; fNominalCov[4]=0.; return; }
67 void SetVtxStart(AliESDVertex *vtx);
71d84967 68 static Double_t GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0);
69 static Double_t GetDeterminant3X3(Double_t matr[][3]);
70 static void GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d);
71 static void GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d);
146c29df 72 static AliESDVertex TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights=0);
dc3719f3 73 void SetFieldkG(Double_t field=-999.) { fFieldkG=field; return; }
74 Double_t GetFieldkG() const {
75 if(fFieldkG<-99.) AliFatal("Field value not set");
76 return fFieldkG; }
07680cae 77
2d57349e 78 protected:
fee9ef0d 79 void HelixVertexFinder();
0c69be49 80 void OneTrackVertFinder();
fee9ef0d 81 Int_t PrepareTracks(TTree &trkTree,Int_t optImpParCut);
82 Bool_t TrackToPoint(AliESDtrack *t,
0bf2e2b4 83 TMatrixD &ri,TMatrixD &wWi,
84 Bool_t uUi3by3=kFALSE) const;
2d57349e 85 void VertexFinder(Int_t optUseWeights=0);
fee9ef0d 86 void VertexFitter(Bool_t useConstraint=kFALSE);
87 void StrLinVertexFinderMinDist(Int_t optUseWeights=0);
eae1677e 88 void TooFewTracks(const AliESD *esdEvent);
89
146c29df 90 AliESDVertex fVert; // vertex after vertex finder
ec1be5d5 91 AliESDVertex *fCurrentVertex; // ESD vertex after fitter
dc3719f3 92 Double_t fFieldkG; // z component of field (kGauss)
07680cae 93 Double_t fNominalPos[3]; // initial knowledge on vertex position
50ff0bcd 94 Double_t fNominalCov[6]; // initial knowledge on vertex position
fee9ef0d 95 Bool_t fConstraint; // true when "mean vertex" was set in
96 // fNominal ... and must be used in the fit
97 Bool_t fOnlyFitter; // primary with one fitter shot only
98 // (use only with beam constraint)
2d57349e 99 Int_t fMinTracks; // minimum number of tracks
07680cae 100 Int_t fMinITSClusters; // minimum number of ITS clusters per track
2d57349e 101 TObjArray fTrkArray; // array with tracks to be processed
ec1be5d5 102 Int_t *fTrksToSkip; // tracks to be skipped for find and fit
103 Int_t fNTrksToSkip; // number of tracks to be skipped
2d57349e 104 Double_t fDCAcut; // maximum DCA between 2 tracks used for vertex
105 Int_t fAlgo; // option for vertex finding algorythm
07680cae 106 Double_t fNSigma; // number of sigmas for d0 cut in PrepareTracks()
fee9ef0d 107 Double_t fMaxd0z0; // value [mm] for sqrt(d0d0+z0z0) cut
108 // in PrepareTracks(1) if fConstraint=kFALSE
50ff0bcd 109 Bool_t fITSin; // if kTRUE (default), use only kITSin tracks
110 // if kFALSE, use all tracks (also TPC only)
111 Bool_t fITSrefit; // if kTRUE (default), use only kITSrefit tracks
112 // if kFALSE, use all tracks (also TPC only)
113 Int_t fDebug; //! debug flag - verbose printing if >0
2d57349e 114 // fAlgo=1 (default) finds minimum-distance point among all selected tracks
115 // approximated as straight lines
116 // and uses errors on track parameters as weights
117 // fAlgo=2 finds minimum-distance point among all the selected tracks
118 // approximated as straight lines
119 // fAlgo=3 finds the average point among DCA points of all pairs of tracks
120 // treated as helices
121 // fAlgo=4 finds the average point among DCA points of all pairs of tracks
122 // approximated as straight lines
123 // and uses errors on track parameters as weights
124 // fAlgo=5 finds the average point among DCA points of all pairs of tracks
125 // approximated as straight lines
126
fe12e09c 127 private:
128 AliVertexerTracks(const AliVertexerTracks & source);
129 AliVertexerTracks & operator=(const AliVertexerTracks & source);
2d57349e 130
146c29df 131 ClassDef(AliVertexerTracks,8) // 3D Vertexing with ESD tracks
2d57349e 132};
133
134#endif