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Update VZERO reco in order to deal with high lumi data. Weighted mean on V0 A and...
[u/mrichter/AliRoot.git] / STEER / AliKFParticleBase.h
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f826d409 1//---------------------------------------------------------------------------------
2// The AliKFParticleBase class
3// .
4// @author S.Gorbunov, I.Kisel
5// @version 1.0
6// @since 13.05.07
7//
8// Class to reconstruct and store the decayed particle parameters.
9// The method is described in CBM-SOFT note 2007-003,
10// ``Reconstruction of decayed particles based on the Kalman filter'',
11// http://www.gsi.de/documents/DOC-2007-May-14-1.pdf
12//
13// This class describes general mathematics which is used by AliKFParticle class
14//
15// -= Copyright &copy ALICE HLT Group =-
16//_________________________________________________________________________________
17
18
19
20#ifndef ALIKFPARTICLEBASE_H
21#define ALIKFPARTICLEBASE_H
22
23#include "TObject.h"
24
25class AliKFParticleBase :public TObject {
26
27 public:
28
29 //*
30 //* ABSTRACT METHODS HAVE TO BE DEFINED IN USER CLASS
31 //*
32
33 //* Virtual method to access the magnetic field
34
35 virtual void GetFieldValue(const Double_t xyz[], Double_t B[]) const = 0;
36
37 //* Virtual methods needed for particle transportation
38 //* One can use particular implementations for collider (only Bz component)
39 //* geometry and for fixed-target (CBM-like) geometry which are provided below
40 //* in TRANSPORT section
41
42 //* Get dS to xyz[] space point
43
44 virtual Double_t GetDStoPoint( const Double_t xyz[] ) const = 0;
45
46 //* Get dS to other particle p (dSp for particle p also returned)
47
48 virtual void GetDStoParticle( const AliKFParticleBase &p,
49 Double_t &DS, Double_t &DSp ) const = 0;
50
51 //* Transport on dS value along trajectory, output to P,C
52
53 virtual void Transport( Double_t dS, Double_t P[], Double_t C[] ) const = 0;
54
55
56
57 //*
58 //* INITIALIZATION
59 //*
60
61 //* Constructor
62
63 AliKFParticleBase();
64
65 //* Destructor
66
e7b09c95 67 virtual ~AliKFParticleBase() { ; }
68
69 //* Initialisation from "cartesian" coordinates ( X Y Z Px Py Pz )
70 //* Parameters, covariance matrix, charge, and mass hypothesis should be provided
71
72 void Initialize( const Double_t Param[], const Double_t Cov[], Int_t Charge, Double_t Mass );
f826d409 73
74 //* Initialise covariance matrix and set current parameters to 0.0
75
76 void Initialize();
77
78 //* Set decay vertex parameters for linearisation
79
80 void SetVtxGuess( Double_t x, Double_t y, Double_t z );
81
82 //*
83 //* ACCESSORS
84 //*
85
86 //* Simple accessors
87
88 Double_t GetX () const { return fP[0]; }
89 Double_t GetY () const { return fP[1]; }
90 Double_t GetZ () const { return fP[2]; }
91 Double_t GetPx () const { return fP[3]; }
92 Double_t GetPy () const { return fP[4]; }
93 Double_t GetPz () const { return fP[5]; }
94 Double_t GetE () const { return fP[6]; }
95 Double_t GetS () const { return fP[7]; }
96 Int_t GetQ () const { return fQ; }
97 Double_t GetChi2 () const { return fChi2; }
98 Int_t GetNDF () const { return fNDF; }
99
100 Double_t GetParameter ( Int_t i ) const { return fP[i]; }
101 Double_t GetCovariance( Int_t i ) const { return fC[i]; }
102 Double_t GetCovariance( Int_t i, Int_t j ) const { return fC[IJ(i,j)]; }
103
104 //* Accessors with calculations( &value, &estimated sigma )
105 //* error flag returned (0 means no error during calculations)
106
706952f5 107 Int_t GetMomentum ( Double_t &P, Double_t &SigmaP ) const ;
108 Int_t GetPt ( Double_t &Pt, Double_t &SigmaPt ) const ;
109 Int_t GetEta ( Double_t &Eta, Double_t &SigmaEta ) const ;
110 Int_t GetPhi ( Double_t &Phi, Double_t &SigmaPhi ) const ;
111 Int_t GetMass ( Double_t &M, Double_t &SigmaM ) const ;
112 Int_t GetDecayLength ( Double_t &L, Double_t &SigmaL ) const ;
446ce366 113 Int_t GetDecayLengthXY ( Double_t &L, Double_t &SigmaL ) const ;
706952f5 114 Int_t GetLifeTime ( Double_t &T, Double_t &SigmaT ) const ;
115 Int_t GetR ( Double_t &R, Double_t &SigmaR ) const ;
f826d409 116
117 //*
118 //* MODIFIERS
119 //*
120
121 Double_t & X () { return fP[0]; }
122 Double_t & Y () { return fP[1]; }
123 Double_t & Z () { return fP[2]; }
124 Double_t & Px () { return fP[3]; }
125 Double_t & Py () { return fP[4]; }
126 Double_t & Pz () { return fP[5]; }
127 Double_t & E () { return fP[6]; }
128 Double_t & S () { return fP[7]; }
129 Int_t & Q () { return fQ; }
130 Double_t & Chi2 () { return fChi2; }
131 Int_t & NDF () { return fNDF; }
132
133 Double_t & Parameter ( Int_t i ) { return fP[i]; }
134 Double_t & Covariance( Int_t i ) { return fC[i]; }
135 Double_t & Covariance( Int_t i, Int_t j ) { return fC[IJ(i,j)]; }
136
137
138 //*
139 //* CONSTRUCTION OF THE PARTICLE BY ITS DAUGHTERS AND MOTHER
140 //* USING THE KALMAN FILTER METHOD
141 //*
142
143
144 //* Simple way to add daughter ex. D0+= Pion;
145
146 void operator +=( const AliKFParticleBase &Daughter );
147
148 //* Add daughter track to the particle
149
150 void AddDaughter( const AliKFParticleBase &Daughter );
151
152 //* Set production vertex
153
154 void SetProductionVertex( const AliKFParticleBase &Vtx );
155
e7b09c95 156 //* Set mass constraint
f826d409 157
e7b09c95 158 void SetMassConstraint( Double_t Mass, Double_t SigmaMass = 0 );
f826d409 159
e7b09c95 160 //* Set no decay length for resonances
161
162 void SetNoDecayLength();
163
164
f826d409 165 //* Everything in one go
166
167 void Construct( const AliKFParticleBase *vDaughters[], Int_t NDaughters,
706952f5 168 const AliKFParticleBase *ProdVtx=0, Double_t Mass=-1, Bool_t IsConstrained=0 );
f826d409 169
170
171 //*
172 //* TRANSPORT
173 //*
174 //* ( main transportation parameter is S = SignedPath/Momentum )
175 //* ( parameters of decay & production vertices are stored locally )
176 //*
177
178
179 //* Transport the particle to its decay vertex
180
181 void TransportToDecayVertex();
182
183 //* Transport the particle to its production vertex
184
185 void TransportToProductionVertex();
186
187 //* Transport the particle on dS parameter (SignedPath/Momentum)
188
189 void TransportToDS( Double_t dS );
190
191 //* Particular extrapolators one can use
192
193 Double_t GetDStoPointBz( Double_t Bz, const Double_t xyz[] ) const;
194
195 void GetDStoParticleBz( Double_t Bz, const AliKFParticleBase &p,
196 Double_t &dS, Double_t &dS1 ) const ;
197
198 // Double_t GetDStoPointCBM( const Double_t xyz[] ) const;
199
200 void TransportBz( Double_t Bz, Double_t dS, Double_t P[], Double_t C[] ) const;
201 void TransportCBM( Double_t dS, Double_t P[], Double_t C[] ) const;
202
203
204 //*
205 //* OTHER UTILITIES
206 //*
207
208 //* Calculate distance from another object [cm]
209
210 Double_t GetDistanceFromVertex( const Double_t vtx[] ) const;
211 Double_t GetDistanceFromVertex( const AliKFParticleBase &Vtx ) const;
616ffc76 212 Double_t GetDistanceFromParticle( const AliKFParticleBase &p ) const;
f826d409 213
214 //* Calculate sqrt(Chi2/ndf) deviation from vertex
215 //* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix
216
217 Double_t GetDeviationFromVertex( const Double_t v[],
218 const Double_t Cv[]=0 ) const;
219 Double_t GetDeviationFromVertex( const AliKFParticleBase &Vtx ) const;
616ffc76 220 Double_t GetDeviationFromParticle( const AliKFParticleBase &p ) const;
f826d409 221
222 //* Subtract the particle from the vertex
223
de0d0ceb 224 void SubtractFromVertex( AliKFParticleBase &Vtx ) const;
225
a65041d0 226 //* Special method for creating gammas
227
228 void ConstructGammaBz( const AliKFParticleBase &daughter1,
229 const AliKFParticleBase &daughter2, double Bz );
230
f826d409 231 protected:
232
233 static Int_t IJ( Int_t i, Int_t j ){
234 return ( j<=i ) ? i*(i+1)/2+j :j*(j+1)/2+i;
235 }
236
237 Double_t & Cij( Int_t i, Int_t j ){ return fC[IJ(i,j)]; }
238
239 void Convert( bool ToProduction );
240 void TransportLine( Double_t S, Double_t P[], Double_t C[] ) const ;
241 Double_t GetDStoPointLine( const Double_t xyz[] ) const;
242
a65041d0 243 static Bool_t InvertSym3( const Double_t A[], Double_t Ainv[] );
244
f826d409 245 static void MultQSQt( const Double_t Q[], const Double_t S[],
246 Double_t SOut[] );
247
706952f5 248 static Double_t GetSCorrection( const Double_t Part[], const Double_t XYZ[] );
249
616ffc76 250 void GetMeasurement( const Double_t XYZ[], Double_t m[], Double_t V[] ) const ;
f826d409 251
252 Double_t fP[8]; //* Main particle parameters {X,Y,Z,Px,Py,Pz,E,S[=DecayLength/P]}
253 Double_t fC[36]; //* Low-triangle covariance matrix of fP
254 Int_t fQ; //* Particle charge
255 Int_t fNDF; //* Number of degrees of freedom
256 Double_t fChi2; //* Chi^2
257
258 Double_t fSFromDecay; //* Distance from decay vertex to current position
259
260 Bool_t fAtProductionVertex; //* Flag shows that the particle error along
261 //* its trajectory is taken from production vertex
262
263 Double_t fVtxGuess[3]; //* Guess for the position of the decay vertex
264 //* ( used for linearisation of equations )
265
266 Bool_t fIsLinearized; //* Flag shows that the guess is present
267
268 ClassDef( AliKFParticleBase, 1 );
269};
270
271#endif