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cab6ff9b | 1 | #ifndef ALIITSVERTEXERTRACKS_H |
2 | #define ALIITSVERTEXERTRACKS_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 primary vertex determination with ITS tracks | |
9 | // | |
10 | // Origin: A.Dainese, Padova, andrea.dainese@pd.infn.it | |
11 | // M.Masera, Torino, massimo.masera@to.infn.it | |
12 | //------------------------------------------------------- | |
13 | ||
14 | /***************************************************************************** | |
15 | * * | |
16 | * This class determines the primary vertex position using ITS tracks. * | |
17 | * This is done in two steps: * | |
18 | * 1) Vertex Finding: a reasonable estimate of the vertex position is * | |
19 | * obtained from a mean of "points of closest approach" between all * | |
20 | * possible pairs of tracks. * | |
21 | * 2) Vertex Fitting: once tracks are propagated to the position given by * | |
22 | * first step, the optimal estimate of the position of vertex is obtained * | |
23 | * from a weighted average of the track positions. A covariance * | |
24 | * matrix and a chi2 for the vertex are given. * | |
25 | * * | |
26 | *****************************************************************************/ | |
27 | ||
28 | #include "AliKalmanTrack.h" | |
29 | #include "AliITSVertexer.h" | |
30 | ||
3a4956bf | 31 | #include <TObjArray.h> |
32 | ||
cab6ff9b | 33 | class TTree; |
cab6ff9b | 34 | class AliITSVertex; |
35 | ||
36 | class AliITSVertexerTracks : public AliITSVertexer { | |
37 | ||
38 | public: | |
39 | // default constructor | |
40 | AliITSVertexerTracks(); | |
41 | // standard constructor | |
88cb7938 | 42 | AliITSVertexerTracks(Double_t field, TString fn, |
43 | Double_t xStart=0,Double_t yStart=0,Int_t useThFr=0); | |
cab6ff9b | 44 | // destructor |
45 | virtual ~AliITSVertexerTracks() {} | |
46 | // return vertex from the set of tracks in the tree | |
47 | AliITSVertex *VertexOnTheFly(TTree &trkTree); | |
48 | // computes the vertex for the current event | |
49 | virtual AliITSVertex* FindVertexForCurrentEvent(Int_t evnumb); | |
88cb7938 | 50 | // computes the vertex for each event and stores it on file |
cab6ff9b | 51 | virtual void FindVertices(); |
52 | virtual void PrintStatus() const; | |
53 | // computes the vertex for the current event | |
54 | void SetField(Double_t field) const | |
55 | { AliKalmanTrack::SetConvConst(100./0.299792458/field); return; } | |
56 | void SetMinTracks(Int_t n=3) { fMinTracks = n; return; } | |
57 | void SetSkipTracks(Int_t n,Int_t *skipped); | |
58 | void SetUseThrustFrame(Int_t utf=0) { fUseThrustFrame = utf; return; } | |
59 | void SetVtxStart(Double_t x=0,Double_t y=0) | |
60 | { fNominalPos[0]=x; fNominalPos[1]=y; return; } | |
61 | ||
62 | private: | |
63 | Double_t fInitPos[3]; // vertex position after vertex finder | |
64 | Double_t fNominalPos[2]; // initial knowledge on vertex position | |
65 | Int_t fMinTracks; // minimum number of tracks | |
66 | Double_t fMaxChi2PerTrack; // maximum contribition to the chi2 | |
67 | Int_t fUseThrustFrame; // if !=0 vertex is given in thrust ref. frame | |
68 | Double_t fPhiThrust; // thrust direction | |
69 | TObjArray fTrkArray; // array with tracks to be processed | |
70 | Int_t *fTrksToSkip; // tracks to be skipped for find and fit | |
71 | Int_t fNTrksToSkip; // number of tracks to be skipped | |
72 | ||
73 | Bool_t CheckField() const; | |
74 | void ComputeMaxChi2PerTrack(Int_t nTracks); | |
75 | Int_t PrepareTracks(TTree &trkTree); | |
76 | void SetPhiThrust(Double_t phi=0.) { fPhiThrust=phi; return; } | |
77 | Double_t SumPl(TTree &momTree,Double_t phi) const; | |
78 | void ThrustFinderXY(); | |
79 | void TooFewTracks(); | |
80 | void VertexFinder(); | |
81 | void VertexFitter(); | |
82 | ||
83 | ClassDef(AliITSVertexerTracks,1) // 3D Vertexing with ITS tracks | |
84 | }; | |
85 | ||
86 | #endif | |
87 | ||
88 | ||
89 |