[u/mrichter/AliRoot.git] / STEER / AliKFParticleBase.h

//---------------------------------------------------------------------------------
// The AliKFParticleBase class
// .
// @author  S.Gorbunov, I.Kisel
// @version 1.0
// @since   13.05.07
// 
// Class to reconstruct and store the decayed particle parameters.
// The method is described in CBM-SOFT note 2007-003, 
// ``Reconstruction of decayed particles based on the Kalman filter'', 
// http://www.gsi.de/documents/DOC-2007-May-14-1.pdf
//
// This class describes general mathematics which is used by AliKFParticle class
// 
//  -= Copyright &copy ALICE HLT Group =-
//_________________________________________________________________________________


#ifndef ALIKFPARTICLEBASE_H
#define ALIKFPARTICLEBASE_H

#include "TObject.h"

class AliKFParticleBase :public TObject {
  
 public:

  //*
  //* ABSTRACT METHODS HAVE TO BE DEFINED IN USER CLASS 
  //* 

  //* Virtual method to access the magnetic field

  virtual void GetFieldValue(const Double_t xyz[], Double_t B[]) const = 0;
  
  //* Virtual methods needed for particle transportation 
  //* One can use particular implementations for collider (only Bz component) 
  //* geometry and for fixed-target (CBM-like) geometry which are provided below 
  //* in TRANSPORT section
 
  //* Get dS to xyz[] space point 

  virtual Double_t GetDStoPoint( const Double_t xyz[] ) const = 0;

  //* Get dS to other particle p (dSp for particle p also returned) 

  virtual void GetDStoParticle( const AliKFParticleBase &p, 
				Double_t &DS, Double_t &DSp ) const = 0;
  
  //* Transport on dS value along trajectory, output to P,C

  virtual void Transport( Double_t dS, Double_t P[], Double_t C[] ) const = 0;


  //*
  //*  INITIALIZATION
  //*

  //* Constructor 

  AliKFParticleBase();

  //* Destructor 

  virtual ~AliKFParticleBase() { ; }

 //* Initialisation from "cartesian" coordinates ( X Y Z Px Py Pz )
 //* Parameters, covariance matrix, charge, and mass hypothesis should be provided 

  void Initialize( const Double_t Param[], const Double_t Cov[], Int_t Charge, Double_t Mass );

  //* Initialise covariance matrix and set current parameters to 0.0 

  void Initialize();

  //* Set decay vertex parameters for linearisation 

  void SetVtxGuess( Double_t x, Double_t y, Double_t z );

  //*
  //*  ACCESSORS
  //*

  //* Simple accessors 

  Double_t GetX    () const { return fP[0]; }
  Double_t GetY    () const { return fP[1]; }
  Double_t GetZ    () const { return fP[2]; }
  Double_t GetPx   () const { return fP[3]; }
  Double_t GetPy   () const { return fP[4]; }
  Double_t GetPz   () const { return fP[5]; }
  Double_t GetE    () const { return fP[6]; }
  Double_t GetS    () const { return fP[7]; }
  Int_t    GetQ    () const { return fQ;    }
  Double_t GetChi2 () const { return fChi2; }
  Int_t    GetNDF  () const { return fNDF;  }
  
  Double_t GetParameter ( Int_t i )        const { return fP[i];       }
  Double_t GetCovariance( Int_t i )        const { return fC[i];       }
  Double_t GetCovariance( Int_t i, Int_t j ) const { return fC[IJ(i,j)]; }

  //* Accessors with calculations( &value, &estimated sigma )
  //* error flag returned (0 means no error during calculations) 

  Int_t GetMomentum    ( Double_t &pmom, Double_t &sigmap ) const ;
  Int_t GetMass        ( Double_t &mass, Double_t &sigmam ) const ;
  Int_t GetDecayLength ( Double_t &dlen, Double_t &sigmal ) const ;
  Int_t GetLifeTime    ( Double_t &tauc, Double_t &sigmat ) const ;

  //*
  //*  MODIFIERS
  //*
  
  Double_t & X    () { return fP[0]; }
  Double_t & Y    () { return fP[1]; }
  Double_t & Z    () { return fP[2]; }
  Double_t & Px   () { return fP[3]; }
  Double_t & Py   () { return fP[4]; }
  Double_t & Pz   () { return fP[5]; }
  Double_t & E    () { return fP[6]; }
  Double_t & S    () { return fP[7]; }
  Int_t    & Q    () { return fQ;    }
  Double_t & Chi2 () { return fChi2; }
  Int_t    & NDF  () { return fNDF;  }

  Double_t & Parameter ( Int_t i )        { return fP[i];       }
  Double_t & Covariance( Int_t i )        { return fC[i];       }
  Double_t & Covariance( Int_t i, Int_t j ) { return fC[IJ(i,j)]; }


  //* 
  //* CONSTRUCTION OF THE PARTICLE BY ITS DAUGHTERS AND MOTHER
  //* USING THE KALMAN FILTER METHOD
  //*


  //* Simple way to add daughter ex. D0+= Pion; 

  void operator +=( const AliKFParticleBase &Daughter );  

  //* Add daughter track to the particle 

  void AddDaughter( const AliKFParticleBase &Daughter );

  //* Set production vertex 

  void SetProductionVertex( const AliKFParticleBase &Vtx );

  //* Set mass constraint 

  void SetMassConstraint( Double_t Mass, Double_t SigmaMass = 0 );
  
  //* Set no decay length for resonances

  void SetNoDecayLength();


  //* Everything in one go  

  void Construct( const AliKFParticleBase *vDaughters[], Int_t NDaughters, 
		  const AliKFParticleBase *ProdVtx=0,   Double_t Mass=-1  );


  //*
  //*                   TRANSPORT
  //* 
  //*  ( main transportation parameter is S = SignedPath/Momentum )
  //*  ( parameters of decay & production vertices are stored locally )
  //*


  //* Transport the particle to its decay vertex 

  void TransportToDecayVertex();

  //* Transport the particle to its production vertex 

  void TransportToProductionVertex();

  //* Transport the particle on dS parameter (SignedPath/Momentum) 

  void TransportToDS( Double_t dS );

  //* Particular extrapolators one can use 

  Double_t GetDStoPointBz( Double_t Bz, const Double_t xyz[] ) const;
  
  void GetDStoParticleBz( Double_t Bz, const AliKFParticleBase &p, 
			  Double_t &dS, Double_t &dS1       ) const ;
 
  // Double_t GetDStoPointCBM( const Double_t xyz[] ) const;
 
   void TransportBz( Double_t Bz, Double_t dS, Double_t P[], Double_t C[] ) const;
   void TransportCBM( Double_t dS, Double_t P[], Double_t C[] ) const;  


  //* 
  //* OTHER UTILITIES
  //*

  //* Calculate distance from another object [cm]

  Double_t GetDistanceFromVertex( const Double_t vtx[] ) const;
  Double_t GetDistanceFromVertex( const AliKFParticleBase &Vtx ) const;
  Double_t GetDistanceFromParticle( const AliKFParticleBase &p ) const;

  //* Calculate sqrt(Chi2/ndf) deviation from vertex
  //* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix

  Double_t GetDeviationFromVertex( const Double_t v[], 
				   const Double_t Cv[]=0 ) const;
  Double_t GetDeviationFromVertex( const AliKFParticleBase &Vtx ) const;
  Double_t GetDeviationFromParticle( const AliKFParticleBase &p ) const;  

  //* Subtract the particle from the vertex  

  void SubtractFromVertex( Double_t v[], Double_t Cv[], 
			   Double_t &vChi2, Int_t vNDF ) const ;
  
 protected:

  static Int_t IJ( Int_t i, Int_t j ){ 
    return ( j<=i ) ? i*(i+1)/2+j :j*(j+1)/2+i;
  }

  Double_t & Cij( Int_t i, Int_t j ){ return fC[IJ(i,j)]; }

  void Convert( bool ToProduction );
  void TransportLine( Double_t S, Double_t P[], Double_t C[] ) const ;
  Double_t GetDStoPointLine( const Double_t xyz[] ) const;

  static void MultQSQt( const Double_t Q[], const Double_t S[], 
			Double_t SOut[] );

  void GetMeasurement( const Double_t XYZ[], Double_t m[], Double_t V[] ) const ;

  Double_t fP[8];  //* Main particle parameters {X,Y,Z,Px,Py,Pz,E,S[=DecayLength/P]}
  Double_t fC[36]; //* Low-triangle covariance matrix of fP
  Int_t    fQ;     //* Particle charge 
  Int_t    fNDF;   //* Number of degrees of freedom 
  Double_t fChi2;  //* Chi^2

  Double_t fSFromDecay; //* Distance from decay vertex to current position

  Bool_t fAtProductionVertex; //* Flag shows that the particle error along
                              //* its trajectory is taken from production vertex    

  Double_t fVtxGuess[3];  //* Guess for the position of the decay vertex 
                          //* ( used for linearisation of equations )

  Bool_t fIsLinearized;   //* Flag shows that the guess is present

  ClassDef( AliKFParticleBase, 1 );
};

#endif
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 &copy 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; }
	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
8ac4fa64	107	Int_t GetMomentum ( Double_t &pmom, Double_t &sigmap ) const ;
	108	Int_t GetMass ( Double_t &mass, Double_t &sigmam ) const ;
	109	Int_t GetDecayLength ( Double_t &dlen, Double_t &sigmal ) const ;
	110	Int_t GetLifeTime ( Double_t &tauc, Double_t &sigmat ) const ;
f826d409	111
	112	//*
	113	//* MODIFIERS
	114	//*
	115
	116	Double_t & X () { return fP[0]; }
	117	Double_t & Y () { return fP[1]; }
	118	Double_t & Z () { return fP[2]; }
	119	Double_t & Px () { return fP[3]; }
	120	Double_t & Py () { return fP[4]; }
	121	Double_t & Pz () { return fP[5]; }
	122	Double_t & E () { return fP[6]; }
	123	Double_t & S () { return fP[7]; }
	124	Int_t & Q () { return fQ; }
	125	Double_t & Chi2 () { return fChi2; }
	126	Int_t & NDF () { return fNDF; }
	127
	128	Double_t & Parameter ( Int_t i ) { return fP[i]; }
	129	Double_t & Covariance( Int_t i ) { return fC[i]; }
	130	Double_t & Covariance( Int_t i, Int_t j ) { return fC[IJ(i,j)]; }
	131
	132
	133	//*
	134	//* CONSTRUCTION OF THE PARTICLE BY ITS DAUGHTERS AND MOTHER
	135	//* USING THE KALMAN FILTER METHOD
	136	//*
	137
	138
	139	//* Simple way to add daughter ex. D0+= Pion;
	140
	141	void operator +=( const AliKFParticleBase &Daughter );
	142
	143	//* Add daughter track to the particle
	144
	145	void AddDaughter( const AliKFParticleBase &Daughter );
	146
	147	//* Set production vertex
	148
	149	void SetProductionVertex( const AliKFParticleBase &Vtx );
	150
e7b09c95	151	//* Set mass constraint
f826d409	152
e7b09c95	153	void SetMassConstraint( Double_t Mass, Double_t SigmaMass = 0 );
f826d409	154
e7b09c95	155	//* Set no decay length for resonances
	156
	157	void SetNoDecayLength();
	158
	159
f826d409	160	//* Everything in one go
	161
	162	void Construct( const AliKFParticleBase *vDaughters[], Int_t NDaughters,
	163	const AliKFParticleBase *ProdVtx=0, Double_t Mass=-1 );
	164
	165
	166	//*
	167	//* TRANSPORT
	168	//*
	169	//* ( main transportation parameter is S = SignedPath/Momentum )
	170	//* ( parameters of decay & production vertices are stored locally )
	171	//*
	172
	173
	174	//* Transport the particle to its decay vertex
	175
	176	void TransportToDecayVertex();
	177
	178	//* Transport the particle to its production vertex
	179
	180	void TransportToProductionVertex();
	181
	182	//* Transport the particle on dS parameter (SignedPath/Momentum)
	183
	184	void TransportToDS( Double_t dS );
	185
	186	//* Particular extrapolators one can use
	187
	188	Double_t GetDStoPointBz( Double_t Bz, const Double_t xyz[] ) const;
	189
	190	void GetDStoParticleBz( Double_t Bz, const AliKFParticleBase &p,
	191	Double_t &dS, Double_t &dS1 ) const ;
	192
	193	// Double_t GetDStoPointCBM( const Double_t xyz[] ) const;
	194
	195	void TransportBz( Double_t Bz, Double_t dS, Double_t P[], Double_t C[] ) const;
	196	void TransportCBM( Double_t dS, Double_t P[], Double_t C[] ) const;
	197
	198
	199	//*
	200	//* OTHER UTILITIES
	201	//*
	202
	203	//* Calculate distance from another object [cm]
	204
	205	Double_t GetDistanceFromVertex( const Double_t vtx[] ) const;
	206	Double_t GetDistanceFromVertex( const AliKFParticleBase &Vtx ) const;
616ffc76	207	Double_t GetDistanceFromParticle( const AliKFParticleBase &p ) const;
f826d409	208
	209	//* Calculate sqrt(Chi2/ndf) deviation from vertex
	210	//* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix
	211
	212	Double_t GetDeviationFromVertex( const Double_t v[],
	213	const Double_t Cv[]=0 ) const;
	214	Double_t GetDeviationFromVertex( const AliKFParticleBase &Vtx ) const;
616ffc76	215	Double_t GetDeviationFromParticle( const AliKFParticleBase &p ) const;
f826d409	216
	217	//* Subtract the particle from the vertex
	218
	219	void SubtractFromVertex( Double_t v[], Double_t Cv[],
	220	Double_t &vChi2, Int_t vNDF ) const ;
	221
	222	protected:
	223
	224	static Int_t IJ( Int_t i, Int_t j ){
	225	return ( j<=i ) ? i(i+1)/2+j :j(j+1)/2+i;
	226	}
	227
	228	Double_t & Cij( Int_t i, Int_t j ){ return fC[IJ(i,j)]; }
	229
	230	void Convert( bool ToProduction );
	231	void TransportLine( Double_t S, Double_t P[], Double_t C[] ) const ;
	232	Double_t GetDStoPointLine( const Double_t xyz[] ) const;
	233
	234	static void MultQSQt( const Double_t Q[], const Double_t S[],
	235	Double_t SOut[] );
	236
616ffc76	237	void GetMeasurement( const Double_t XYZ[], Double_t m[], Double_t V[] ) const ;
f826d409	238
	239	Double_t fP[8]; //* Main particle parameters {X,Y,Z,Px,Py,Pz,E,S[=DecayLength/P]}
	240	Double_t fC[36]; //* Low-triangle covariance matrix of fP
	241	Int_t fQ; //* Particle charge
	242	Int_t fNDF; //* Number of degrees of freedom
	243	Double_t fChi2; //* Chi^2
	244
	245	Double_t fSFromDecay; //* Distance from decay vertex to current position
	246
	247	Bool_t fAtProductionVertex; //* Flag shows that the particle error along
	248	//* its trajectory is taken from production vertex
	249
	250	Double_t fVtxGuess[3]; //* Guess for the position of the decay vertex
	251	//* ( used for linearisation of equations )
	252
	253	Bool_t fIsLinearized; //* Flag shows that the guess is present
	254
	255	ClassDef( AliKFParticleBase, 1 );
	256	};
	257
	258	#endif