]>
Commit | Line | Data |
---|---|---|
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 © ALICE HLT Group =- | |
16 | //_________________________________________________________________________________ | |
17 | ||
18 | ||
19 | ||
20 | #ifndef ALIKFPARTICLEBASE_H | |
21 | #define ALIKFPARTICLEBASE_H | |
22 | ||
23 | #include "TObject.h" | |
24 | ||
25 | class 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; } | |
91b25235 | 99 | |
100 | const Double_t& X () const { return fP[0]; } | |
101 | const Double_t& Y () const { return fP[1]; } | |
102 | const Double_t& Z () const { return fP[2]; } | |
103 | const Double_t& Px () const { return fP[3]; } | |
104 | const Double_t& Py () const { return fP[4]; } | |
105 | const Double_t& Pz () const { return fP[5]; } | |
106 | const Double_t& E () const { return fP[6]; } | |
107 | const Double_t& S () const { return fP[7]; } | |
108 | const Int_t & Q () const { return fQ; } | |
109 | const Double_t& Chi2 () const { return fChi2; } | |
110 | const Int_t & NDF () const { return fNDF; } | |
111 | ||
f826d409 | 112 | |
113 | Double_t GetParameter ( Int_t i ) const { return fP[i]; } | |
114 | Double_t GetCovariance( Int_t i ) const { return fC[i]; } | |
115 | Double_t GetCovariance( Int_t i, Int_t j ) const { return fC[IJ(i,j)]; } | |
116 | ||
117 | //* Accessors with calculations( &value, &estimated sigma ) | |
118 | //* error flag returned (0 means no error during calculations) | |
119 | ||
706952f5 | 120 | Int_t GetMomentum ( Double_t &P, Double_t &SigmaP ) const ; |
121 | Int_t GetPt ( Double_t &Pt, Double_t &SigmaPt ) const ; | |
122 | Int_t GetEta ( Double_t &Eta, Double_t &SigmaEta ) const ; | |
123 | Int_t GetPhi ( Double_t &Phi, Double_t &SigmaPhi ) const ; | |
124 | Int_t GetMass ( Double_t &M, Double_t &SigmaM ) const ; | |
125 | Int_t GetDecayLength ( Double_t &L, Double_t &SigmaL ) const ; | |
446ce366 | 126 | Int_t GetDecayLengthXY ( Double_t &L, Double_t &SigmaL ) const ; |
706952f5 | 127 | Int_t GetLifeTime ( Double_t &T, Double_t &SigmaT ) const ; |
128 | Int_t GetR ( Double_t &R, Double_t &SigmaR ) const ; | |
f826d409 | 129 | |
130 | //* | |
131 | //* MODIFIERS | |
132 | //* | |
133 | ||
134 | Double_t & X () { return fP[0]; } | |
135 | Double_t & Y () { return fP[1]; } | |
136 | Double_t & Z () { return fP[2]; } | |
137 | Double_t & Px () { return fP[3]; } | |
138 | Double_t & Py () { return fP[4]; } | |
139 | Double_t & Pz () { return fP[5]; } | |
140 | Double_t & E () { return fP[6]; } | |
141 | Double_t & S () { return fP[7]; } | |
142 | Int_t & Q () { return fQ; } | |
143 | Double_t & Chi2 () { return fChi2; } | |
144 | Int_t & NDF () { return fNDF; } | |
145 | ||
91b25235 | 146 | |
147 | ||
f826d409 | 148 | Double_t & Parameter ( Int_t i ) { return fP[i]; } |
149 | Double_t & Covariance( Int_t i ) { return fC[i]; } | |
150 | Double_t & Covariance( Int_t i, Int_t j ) { return fC[IJ(i,j)]; } | |
151 | ||
152 | ||
153 | //* | |
154 | //* CONSTRUCTION OF THE PARTICLE BY ITS DAUGHTERS AND MOTHER | |
155 | //* USING THE KALMAN FILTER METHOD | |
156 | //* | |
157 | ||
158 | ||
159 | //* Simple way to add daughter ex. D0+= Pion; | |
160 | ||
161 | void operator +=( const AliKFParticleBase &Daughter ); | |
162 | ||
163 | //* Add daughter track to the particle | |
164 | ||
165 | void AddDaughter( const AliKFParticleBase &Daughter ); | |
166 | ||
167 | //* Set production vertex | |
168 | ||
169 | void SetProductionVertex( const AliKFParticleBase &Vtx ); | |
170 | ||
e7b09c95 | 171 | //* Set mass constraint |
f826d409 | 172 | |
e7b09c95 | 173 | void SetMassConstraint( Double_t Mass, Double_t SigmaMass = 0 ); |
f826d409 | 174 | |
e7b09c95 | 175 | //* Set no decay length for resonances |
176 | ||
177 | void SetNoDecayLength(); | |
178 | ||
179 | ||
f826d409 | 180 | //* Everything in one go |
181 | ||
182 | void Construct( const AliKFParticleBase *vDaughters[], Int_t NDaughters, | |
706952f5 | 183 | const AliKFParticleBase *ProdVtx=0, Double_t Mass=-1, Bool_t IsConstrained=0 ); |
f826d409 | 184 | |
185 | ||
186 | //* | |
187 | //* TRANSPORT | |
188 | //* | |
189 | //* ( main transportation parameter is S = SignedPath/Momentum ) | |
190 | //* ( parameters of decay & production vertices are stored locally ) | |
191 | //* | |
192 | ||
193 | ||
194 | //* Transport the particle to its decay vertex | |
195 | ||
196 | void TransportToDecayVertex(); | |
197 | ||
198 | //* Transport the particle to its production vertex | |
199 | ||
200 | void TransportToProductionVertex(); | |
201 | ||
202 | //* Transport the particle on dS parameter (SignedPath/Momentum) | |
203 | ||
204 | void TransportToDS( Double_t dS ); | |
205 | ||
206 | //* Particular extrapolators one can use | |
207 | ||
208 | Double_t GetDStoPointBz( Double_t Bz, const Double_t xyz[] ) const; | |
209 | ||
210 | void GetDStoParticleBz( Double_t Bz, const AliKFParticleBase &p, | |
211 | Double_t &dS, Double_t &dS1 ) const ; | |
212 | ||
213 | // Double_t GetDStoPointCBM( const Double_t xyz[] ) const; | |
214 | ||
215 | void TransportBz( Double_t Bz, Double_t dS, Double_t P[], Double_t C[] ) const; | |
216 | void TransportCBM( Double_t dS, Double_t P[], Double_t C[] ) const; | |
217 | ||
218 | ||
219 | //* | |
220 | //* OTHER UTILITIES | |
221 | //* | |
222 | ||
223 | //* Calculate distance from another object [cm] | |
224 | ||
225 | Double_t GetDistanceFromVertex( const Double_t vtx[] ) const; | |
226 | Double_t GetDistanceFromVertex( const AliKFParticleBase &Vtx ) const; | |
616ffc76 | 227 | Double_t GetDistanceFromParticle( const AliKFParticleBase &p ) const; |
f826d409 | 228 | |
229 | //* Calculate sqrt(Chi2/ndf) deviation from vertex | |
230 | //* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix | |
231 | ||
232 | Double_t GetDeviationFromVertex( const Double_t v[], | |
233 | const Double_t Cv[]=0 ) const; | |
234 | Double_t GetDeviationFromVertex( const AliKFParticleBase &Vtx ) const; | |
616ffc76 | 235 | Double_t GetDeviationFromParticle( const AliKFParticleBase &p ) const; |
f826d409 | 236 | |
237 | //* Subtract the particle from the vertex | |
238 | ||
de0d0ceb | 239 | void SubtractFromVertex( AliKFParticleBase &Vtx ) const; |
240 | ||
a65041d0 | 241 | //* Special method for creating gammas |
242 | ||
243 | void ConstructGammaBz( const AliKFParticleBase &daughter1, | |
244 | const AliKFParticleBase &daughter2, double Bz ); | |
245 | ||
f826d409 | 246 | protected: |
247 | ||
248 | static Int_t IJ( Int_t i, Int_t j ){ | |
249 | return ( j<=i ) ? i*(i+1)/2+j :j*(j+1)/2+i; | |
250 | } | |
251 | ||
252 | Double_t & Cij( Int_t i, Int_t j ){ return fC[IJ(i,j)]; } | |
253 | ||
254 | void Convert( bool ToProduction ); | |
255 | void TransportLine( Double_t S, Double_t P[], Double_t C[] ) const ; | |
256 | Double_t GetDStoPointLine( const Double_t xyz[] ) const; | |
257 | ||
a65041d0 | 258 | static Bool_t InvertSym3( const Double_t A[], Double_t Ainv[] ); |
259 | ||
f826d409 | 260 | static void MultQSQt( const Double_t Q[], const Double_t S[], |
261 | Double_t SOut[] ); | |
262 | ||
706952f5 | 263 | static Double_t GetSCorrection( const Double_t Part[], const Double_t XYZ[] ); |
264 | ||
616ffc76 | 265 | void GetMeasurement( const Double_t XYZ[], Double_t m[], Double_t V[] ) const ; |
f826d409 | 266 | |
267 | Double_t fP[8]; //* Main particle parameters {X,Y,Z,Px,Py,Pz,E,S[=DecayLength/P]} | |
268 | Double_t fC[36]; //* Low-triangle covariance matrix of fP | |
269 | Int_t fQ; //* Particle charge | |
270 | Int_t fNDF; //* Number of degrees of freedom | |
271 | Double_t fChi2; //* Chi^2 | |
272 | ||
273 | Double_t fSFromDecay; //* Distance from decay vertex to current position | |
274 | ||
275 | Bool_t fAtProductionVertex; //* Flag shows that the particle error along | |
276 | //* its trajectory is taken from production vertex | |
277 | ||
278 | Double_t fVtxGuess[3]; //* Guess for the position of the decay vertex | |
279 | //* ( used for linearisation of equations ) | |
280 | ||
281 | Bool_t fIsLinearized; //* Flag shows that the guess is present | |
282 | ||
283 | ClassDef( AliKFParticleBase, 1 ); | |
284 | }; | |
285 | ||
286 | #endif |