[u/mrichter/AliRoot.git] / STEER / AliKFParticle.cxx

//----------------------------------------------------------------------------
// Implementation of the AliKFParticle 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 is ALICE interface to general mathematics in AliKFParticleCore
// 
//  -= Copyright &copy ALICE HLT Group =-
//____________________________________________________________________________


#include "AliKFParticle.h"
#include "TDatabasePDG.h"
#include "TParticlePDG.h"
#include "AliVTrack.h"
#include "AliVVertex.h"

ClassImp(AliKFParticle)

Double_t AliKFParticle::fgBz = -5.;  //* Bz compoment of the magnetic field

AliKFParticle::AliKFParticle( const AliKFParticle &d1, const AliKFParticle &d2, Bool_t gamma )
{
  if (!gamma) {
    AliKFParticle mother;
    mother+= d1;
    mother+= d2;
    *this = mother;
  } else
    ConstructGamma(d1, d2);
}

void AliKFParticle::Create( const Double_t Param[], const Double_t Cov[], Int_t Charge, Int_t PID )
{
  // Constructor from "cartesian" track, PID hypothesis should be provided
  //
  // Param[6] = { X, Y, Z, Px, Py, Pz } - position and momentum
  // Cov [21] = lower-triangular part of the covariance matrix:
  //
  //                (  0  .  .  .  .  . )
  //                (  1  2  .  .  .  . )
  //  Cov. matrix = (  3  4  5  .  .  . ) - numbering of covariance elements in Cov[]
  //                (  6  7  8  9  .  . )
  //                ( 10 11 12 13 14  . )
  //                ( 15 16 17 18 19 20 )
  Double_t C[21];
  for( int i=0; i<21; i++ ) C[i] = Cov[i];
  
  TParticlePDG* particlePDG = TDatabasePDG::Instance()->GetParticle(PID);
  Double_t mass = (particlePDG) ? particlePDG->Mass() :0.13957;
  
  AliKFParticleBase::Initialize( Param, C, Charge, mass );
}

AliKFParticle::AliKFParticle( const AliVTrack &track, Int_t PID )
{
  // Constructor from ALICE track, PID hypothesis should be provided

  track.GetXYZ(fP);
  track.PxPyPz(fP+3);
  fQ = track.Charge();
  track.GetCovarianceXYZPxPyPz( fC );
  Create(fP,fC,fQ,PID);
}

AliKFParticle::AliKFParticle( const AliVVertex &vertex )
{
  // Constructor from ALICE vertex

  vertex.GetXYZ( fP );
  vertex.GetCovarianceMatrix( fC );  
  fChi2 = vertex.GetChi2();
  fNDF = 2*vertex.GetNContributors() - 3;
  fQ = 0;
  fAtProductionVertex = 0;
  fIsLinearized = 0;
  fSFromDecay = 0;
}

void AliKFParticle::GetExternalTrackParam( const AliKFParticleBase &p, Double_t &X, Double_t &Alpha, Double_t P[5] ) 
{
  // Conversion to AliExternalTrackParam parameterization

  Double_t cosA = p.GetPx(), sinA = p.GetPy(); 
  Double_t pt = TMath::Sqrt(cosA*cosA + sinA*sinA);
  Double_t pti = 0;
  if( pt<1.e-4 ){
    cosA = 1;
    sinA = 0;
  } else {
    pti = 1./pt;
    cosA*=pti;
    sinA*=pti;
  }
  Alpha = TMath::ATan2(sinA,cosA);  
  X   = p.GetX()*cosA + p.GetY()*sinA;   
  P[0]= p.GetY()*cosA - p.GetX()*sinA;
  P[1]= p.GetZ();
  P[2]= 0;
  P[3]= p.GetPz()*pti;
  P[4]= p.GetQ()*pti;
}

Bool_t AliKFParticle::GetDistanceFromVertexXY( const Double_t vtx[], const Double_t Cv[], Double_t &val, Double_t &err ) const
{
  //* Calculate DCA distance from vertex (transverse impact parameter) in XY
  //* v = [xy], Cv=[Cxx,Cxy,Cyy ]-covariance matrix

  Bool_t ret = 0;
  
  Double_t mP[8];
  Double_t mC[36];
  
  Transport( GetDStoPoint(vtx), mP, mC );  

  Double_t dx = mP[0] - vtx[0];
  Double_t dy = mP[1] - vtx[1];
  Double_t px = mP[3];
  Double_t py = mP[4];
  Double_t pt = TMath::Sqrt(px*px + py*py);
  Double_t ex=0, ey=0;
  if( pt<1.e-4 ){
    ret = 1;
    pt = 1.;
    val = 1.e4;
  } else{
    ex = px/pt;
    ey = py/pt;
    val = dy*ex - dx*ey;
  }

  Double_t h0 = -ey;
  Double_t h1 = ex;
  Double_t h3 = (dy*ey + dx*ex)*ey/pt;
  Double_t h4 = -(dy*ey + dx*ex)*ex/pt;
  
  err = 
    h0*(h0*GetCovariance(0,0) + h1*GetCovariance(0,1) + h3*GetCovariance(0,3) + h4*GetCovariance(0,4) ) +
    h1*(h0*GetCovariance(1,0) + h1*GetCovariance(1,1) + h3*GetCovariance(1,3) + h4*GetCovariance(1,4) ) +
    h3*(h0*GetCovariance(3,0) + h1*GetCovariance(3,1) + h3*GetCovariance(3,3) + h4*GetCovariance(3,4) ) +
    h4*(h0*GetCovariance(4,0) + h1*GetCovariance(4,1) + h3*GetCovariance(4,3) + h4*GetCovariance(4,4) );

  if( Cv ){
    err+= h0*(h0*Cv[0] + h1*Cv[1] ) + h1*(h0*Cv[1] + h1*Cv[2] ); 
  }

  err = TMath::Sqrt(TMath::Abs(err));

  return ret;
}

Bool_t AliKFParticle::GetDistanceFromVertexXY( const Double_t vtx[], Double_t &val, Double_t &err ) const
{
  return GetDistanceFromVertexXY( vtx, 0, val, err );
}


Bool_t AliKFParticle::GetDistanceFromVertexXY( const AliKFParticle &Vtx, Double_t &val, Double_t &err ) const 
{
  //* Calculate distance from vertex [cm] in XY-plane

  return GetDistanceFromVertexXY( Vtx.fP, Vtx.fC, val, err );
}

Bool_t AliKFParticle::GetDistanceFromVertexXY( const AliVVertex &Vtx, Double_t &val, Double_t &err ) const 
{
  //* Calculate distance from vertex [cm] in XY-plane

  return GetDistanceFromVertexXY( AliKFParticle(Vtx), val, err );
}

Double_t AliKFParticle::GetDistanceFromVertexXY( const Double_t vtx[] ) const
{
  //* Calculate distance from vertex [cm] in XY-plane
  Double_t val, err;
  GetDistanceFromVertexXY( vtx, 0, val, err );
  return val;
}

Double_t AliKFParticle::GetDistanceFromVertexXY( const AliKFParticle &Vtx ) const 
{
  //* Calculate distance from vertex [cm] in XY-plane

  return GetDistanceFromVertexXY( Vtx.fP );
}

Double_t AliKFParticle::GetDistanceFromVertexXY( const AliVVertex &Vtx ) const 
{
  //* Calculate distance from vertex [cm] in XY-plane

  return GetDistanceFromVertexXY( AliKFParticle(Vtx).fP );
}

Double_t AliKFParticle::GetDistanceFromParticleXY( const AliKFParticle &p ) const 
{
  //* Calculate distance to other particle [cm]

  Double_t dS, dS1;
  GetDStoParticleXY( p, dS, dS1 );   
  Double_t mP[8], mC[36], mP1[8], mC1[36];
  Transport( dS, mP, mC ); 
  p.Transport( dS1, mP1, mC1 ); 
  Double_t dx = mP[0]-mP1[0]; 
  Double_t dy = mP[1]-mP1[1]; 
  return TMath::Sqrt(dx*dx+dy*dy);
}

Double_t AliKFParticle::GetDeviationFromParticleXY( const AliKFParticle &p ) const 
{
  //* Calculate sqrt(Chi2/ndf) deviation from other particle

  Double_t dS, dS1;
  GetDStoParticleXY( p, dS, dS1 );   
  Double_t mP1[8], mC1[36];
  p.Transport( dS1, mP1, mC1 ); 

  Double_t d[2]={ fP[0]-mP1[0], fP[1]-mP1[1] };

  Double_t sigmaS = .1+10.*TMath::Sqrt( (d[0]*d[0]+d[1]*d[1] )/
					(mP1[3]*mP1[3]+mP1[4]*mP1[4] )  );

  Double_t h[2] = { mP1[3]*sigmaS, mP1[4]*sigmaS };       
  
  mC1[0] +=h[0]*h[0];
  mC1[1] +=h[1]*h[0]; 
  mC1[2] +=h[1]*h[1]; 

  return GetDeviationFromVertexXY( mP1, mC1 )*TMath::Sqrt(2./1.);
}


Double_t AliKFParticle::GetDeviationFromVertexXY( const Double_t vtx[], const Double_t Cv[] ) const 
{
  //* Calculate sqrt(Chi2/ndf) deviation from vertex
  //* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix

  Double_t val, err;
  Bool_t problem = GetDistanceFromVertexXY( vtx, Cv, val, err );
  if( problem || err<1.e-20 ) return 1.e4;
  else return val/err;
}


Double_t AliKFParticle::GetDeviationFromVertexXY( const AliKFParticle &Vtx ) const  
{
  //* Calculate sqrt(Chi2/ndf) deviation from vertex
  //* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix

  return GetDeviationFromVertexXY( Vtx.fP, Vtx.fC );
}

Double_t AliKFParticle::GetDeviationFromVertexXY( const AliVVertex &Vtx ) const 
{
  //* Calculate sqrt(Chi2/ndf) deviation from vertex
  //* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix

  AliKFParticle v(Vtx);
  return GetDeviationFromVertexXY( v.fP, v.fC );
}

Double_t AliKFParticle::GetAngle  ( const AliKFParticle &p ) const 
{
  //* Calculate the opening angle between two particles

  Double_t dS, dS1;
  GetDStoParticle( p, dS, dS1 );   
  Double_t mP[8], mC[36], mP1[8], mC1[36];
  Transport( dS, mP, mC ); 
  p.Transport( dS1, mP1, mC1 ); 
  Double_t n = TMath::Sqrt( mP[3]*mP[3] + mP[4]*mP[4] + mP[5]*mP[5] );
  Double_t n1= TMath::Sqrt( mP1[3]*mP1[3] + mP1[4]*mP1[4] + mP1[5]*mP1[5] );
  n*=n1;
  Double_t a = 0;
  if( n>1.e-8 ) a = ( mP[3]*mP1[3] + mP[4]*mP1[4] + mP[5]*mP1[5] )/n;
  if (TMath::Abs(a)<1.) a = TMath::ACos(a);
  else a = (a>=0) ?0 :TMath::Pi();
  return a;
}

Double_t AliKFParticle::GetAngleXY( const AliKFParticle &p ) const 
{
  //* Calculate the opening angle between two particles in XY plane

  Double_t dS, dS1;
  GetDStoParticleXY( p, dS, dS1 );   
  Double_t mP[8], mC[36], mP1[8], mC1[36];
  Transport( dS, mP, mC ); 
  p.Transport( dS1, mP1, mC1 ); 
  Double_t n = TMath::Sqrt( mP[3]*mP[3] + mP[4]*mP[4] );
  Double_t n1= TMath::Sqrt( mP1[3]*mP1[3] + mP1[4]*mP1[4] );
  n*=n1;
  Double_t a = 0;
  if( n>1.e-8 ) a = ( mP[3]*mP1[3] + mP[4]*mP1[4] )/n;
  if (TMath::Abs(a)<1.) a = TMath::ACos(a);
  else a = (a>=0) ?0 :TMath::Pi();
  return a;
}

Double_t AliKFParticle::GetAngleRZ( const AliKFParticle &p ) const 
{
  //* Calculate the opening angle between two particles in RZ plane

  Double_t dS, dS1;
  GetDStoParticle( p, dS, dS1 );   
  Double_t mP[8], mC[36], mP1[8], mC1[36];
  Transport( dS, mP, mC ); 
  p.Transport( dS1, mP1, mC1 ); 
  Double_t nr = TMath::Sqrt( mP[3]*mP[3] + mP[4]*mP[4] );
  Double_t n1r= TMath::Sqrt( mP1[3]*mP1[3] + mP1[4]*mP1[4]  );
  Double_t n = TMath::Sqrt( nr*nr + mP[5]*mP[5] );
  Double_t n1= TMath::Sqrt( n1r*n1r + mP1[5]*mP1[5] );
  n*=n1;
  Double_t a = 0;
  if( n>1.e-8 ) a = ( nr*n1r +mP[5]*mP1[5])/n; 
  if (TMath::Abs(a)<1.) a = TMath::ACos(a);
  else a = (a>=0) ?0 :TMath::Pi();
  return a;
}


/*

#include "AliExternalTrackParam.h"

void AliKFParticle::GetDStoParticleALICE( const AliKFParticleBase &p, 
					   Double_t &DS, Double_t &DS1 ) 
  const
{ 
  DS = DS1 = 0;   
  Double_t x1, a1, x2, a2;
  Double_t par1[5], par2[5], cov[15];
  for(int i=0; i<15; i++) cov[i] = 0;
  cov[0] = cov[2] = cov[5] = cov[9] = cov[14] = .001;

  GetExternalTrackParam( *this, x1, a1, par1 );
  GetExternalTrackParam( p, x2, a2, par2 );

  AliExternalTrackParam t1(x1,a1, par1, cov);
  AliExternalTrackParam t2(x2,a2, par2, cov);

  Double_t xe1=0, xe2=0;
  t1.GetDCA( &t2, -GetFieldAlice(), xe1, xe2 );
  t1.PropagateTo( xe1, -GetFieldAlice() );
  t2.PropagateTo( xe2, -GetFieldAlice() );

  Double_t xyz1[3], xyz2[3];
  t1.GetXYZ( xyz1 );
  t2.GetXYZ( xyz2 );
  
  DS = GetDStoPoint( xyz1 );
  DS1 = p.GetDStoPoint( xyz2 );

  return;
}
*/
Commit	Line	Data
f826d409	1	//----------------------------------------------------------------------------
	2	// Implementation of the AliKFParticle 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 is ALICE interface to general mathematics in AliKFParticleCore
	14	//
	15	// -= Copyright &copy ALICE HLT Group =-
	16	//____________________________________________________________________________
	17
	18
	19	#include "AliKFParticle.h"
	20	#include "TDatabasePDG.h"
	21	#include "TParticlePDG.h"
706952f5	22	#include "AliVTrack.h"
cfb5a2e1	23	#include "AliVVertex.h"
f826d409	24
effa6338	25	ClassImp(AliKFParticle)
f826d409	26
616ffc76	27	Double_t AliKFParticle::fgBz = -5.; //* Bz compoment of the magnetic field
f826d409	28
537b06a4	29	AliKFParticle::AliKFParticle( const AliKFParticle &d1, const AliKFParticle &d2, Bool_t gamma )
	30	{
	31	if (!gamma) {
	32	AliKFParticle mother;
	33	mother+= d1;
	34	mother+= d2;
	35	*this = mother;
	36	} else
	37	ConstructGamma(d1, d2);
	38	}
	39
7972a8db	40	void AliKFParticle::Create( const Double_t Param[], const Double_t Cov[], Int_t Charge, Int_t PID )
f826d409	41	{
e7b09c95	42	// Constructor from "cartesian" track, PID hypothesis should be provided
	43	//
	44	// Param[6] = { X, Y, Z, Px, Py, Pz } - position and momentum
	45	// Cov [21] = lower-triangular part of the covariance matrix:
	46	//
	47	// ( 0 . . . . . )
	48	// ( 1 2 . . . . )
	49	// Cov. matrix = ( 3 4 5 . . . ) - numbering of covariance elements in Cov[]
	50	// ( 6 7 8 9 . . )
	51	// ( 10 11 12 13 14 . )
	52	// ( 15 16 17 18 19 20 )
706952f5	53	Double_t C[21];
	54	for( int i=0; i<21; i++ ) C[i] = Cov[i];
	55
f826d409	56	TParticlePDG* particlePDG = TDatabasePDG::Instance()->GetParticle(PID);
f826d409	57	Double_t mass = (particlePDG) ? particlePDG->Mass() :0.13957;
e7b09c95	58
706952f5	59	AliKFParticleBase::Initialize( Param, C, Charge, mass );
e7b09c95	60	}
616ffc76	61
706952f5	62	AliKFParticle::AliKFParticle( const AliVTrack &track, Int_t PID )
e7b09c95	63	{
e7b09c95	64	// Constructor from ALICE track, PID hypothesis should be provided
616ffc76	65
b63c3605	66	track.GetXYZ(fP);
706952f5	67	track.PxPyPz(fP+3);
706952f5	68	fQ = track.Charge();
f826d409	69	track.GetCovarianceXYZPxPyPz( fC );
7972a8db	70	Create(fP,fC,fQ,PID);
f826d409	71	}
f826d409	72
706952f5	73	AliKFParticle::AliKFParticle( const AliVVertex &vertex )
f826d409	74	{
	75	// Constructor from ALICE vertex
	76
	77	vertex.GetXYZ( fP );
706952f5	78	vertex.GetCovarianceMatrix( fC );
f826d409	79	fChi2 = vertex.GetChi2();
	80	fNDF = 2*vertex.GetNContributors() - 3;
	81	fQ = 0;
	82	fAtProductionVertex = 0;
	83	fIsLinearized = 0;
	84	fSFromDecay = 0;
	85	}
616ffc76	86
616ffc76	87	void AliKFParticle::GetExternalTrackParam( const AliKFParticleBase &p, Double_t &X, Double_t &Alpha, Double_t P[5] )
616ffc76	88	{
e7b09c95	89	// Conversion to AliExternalTrackParam parameterization
e7b09c95	90
616ffc76	91	Double_t cosA = p.GetPx(), sinA = p.GetPy();
	92	Double_t pt = TMath::Sqrt(cosAcosA + sinAsinA);
	93	Double_t pti = 0;
	94	if( pt<1.e-4 ){
	95	cosA = 1;
	96	sinA = 0;
	97	} else {
	98	pti = 1./pt;
	99	cosA*=pti;
	100	sinA*=pti;
	101	}
	102	Alpha = TMath::ATan2(sinA,cosA);
	103	X = p.GetX()cosA + p.GetY()sinA;
	104	P[0]= p.GetY()cosA - p.GetX()sinA;
	105	P[1]= p.GetZ();
	106	P[2]= 0;
	107	P[3]= p.GetPz()*pti;
	108	P[4]= p.GetQ()*pti;
	109	}
	110
446ce366	111	Bool_t AliKFParticle::GetDistanceFromVertexXY( const Double_t vtx[], const Double_t Cv[], Double_t &val, Double_t &err ) const
	112	{
	113	//* Calculate DCA distance from vertex (transverse impact parameter) in XY
	114	//* v = [xy], Cv=[Cxx,Cxy,Cyy ]-covariance matrix
	115
	116	Bool_t ret = 0;
	117
	118	Double_t mP[8];
	119	Double_t mC[36];
	120
	121	Transport( GetDStoPoint(vtx), mP, mC );
	122
	123	Double_t dx = mP[0] - vtx[0];
	124	Double_t dy = mP[1] - vtx[1];
	125	Double_t px = mP[3];
	126	Double_t py = mP[4];
	127	Double_t pt = TMath::Sqrt(pxpx + pypy);
	128	Double_t ex=0, ey=0;
	129	if( pt<1.e-4 ){
	130	ret = 1;
	131	pt = 1.;
	132	val = 1.e4;
	133	} else{
	134	ex = px/pt;
924a4a7b	135	ey = py/pt;
446ce366	136	val = dyex - dxey;
446ce366	137	}
616ffc76	138
446ce366	139	Double_t h0 = -ey;
	140	Double_t h1 = ex;
	141	Double_t h3 = (dyey + dxex)*ey/pt;
	142	Double_t h4 = -(dyey + dxex)*ex/pt;
	143
	144	err =
	145	h0(h0GetCovariance(0,0) + h1GetCovariance(0,1) + h3GetCovariance(0,3) + h4*GetCovariance(0,4) ) +
	146	h1(h0GetCovariance(1,0) + h1GetCovariance(1,1) + h3GetCovariance(1,3) + h4*GetCovariance(1,4) ) +
	147	h3(h0GetCovariance(3,0) + h1GetCovariance(3,1) + h3GetCovariance(3,3) + h4*GetCovariance(3,4) ) +
	148	h4(h0GetCovariance(4,0) + h1GetCovariance(4,1) + h3GetCovariance(4,3) + h4*GetCovariance(4,4) );
616ffc76	149
446ce366	150	if( Cv ){
	151	err+= h0(h0Cv[0] + h1Cv[1] ) + h1(h0Cv[1] + h1Cv[2] );
	152	}
	153
	154	err = TMath::Sqrt(TMath::Abs(err));
	155
	156	return ret;
	157	}
	158
	159	Bool_t AliKFParticle::GetDistanceFromVertexXY( const Double_t vtx[], Double_t &val, Double_t &err ) const
	160	{
	161	return GetDistanceFromVertexXY( vtx, 0, val, err );
	162	}
	163
	164
	165	Bool_t AliKFParticle::GetDistanceFromVertexXY( const AliKFParticle &Vtx, Double_t &val, Double_t &err ) const
e7b09c95	166	{
	167	//* Calculate distance from vertex [cm] in XY-plane
	168
446ce366	169	return GetDistanceFromVertexXY( Vtx.fP, Vtx.fC, val, err );
	170	}
	171
	172	Bool_t AliKFParticle::GetDistanceFromVertexXY( const AliVVertex &Vtx, Double_t &val, Double_t &err ) const
	173	{
	174	//* Calculate distance from vertex [cm] in XY-plane
	175
	176	return GetDistanceFromVertexXY( AliKFParticle(Vtx), val, err );
	177	}
	178
	179	Double_t AliKFParticle::GetDistanceFromVertexXY( const Double_t vtx[] ) const
	180	{
	181	//* Calculate distance from vertex [cm] in XY-plane
	182	Double_t val, err;
	183	GetDistanceFromVertexXY( vtx, 0, val, err );
	184	return val;
e7b09c95	185	}
	186
	187	Double_t AliKFParticle::GetDistanceFromVertexXY( const AliKFParticle &Vtx ) const
	188	{
	189	//* Calculate distance from vertex [cm] in XY-plane
	190
	191	return GetDistanceFromVertexXY( Vtx.fP );
	192	}
	193
706952f5	194	Double_t AliKFParticle::GetDistanceFromVertexXY( const AliVVertex &Vtx ) const
e7b09c95	195	{
	196	//* Calculate distance from vertex [cm] in XY-plane
	197
	198	return GetDistanceFromVertexXY( AliKFParticle(Vtx).fP );
	199	}
	200
	201	Double_t AliKFParticle::GetDistanceFromParticleXY( const AliKFParticle &p ) const
	202	{
	203	//* Calculate distance to other particle [cm]
	204
	205	Double_t dS, dS1;
	206	GetDStoParticleXY( p, dS, dS1 );
	207	Double_t mP[8], mC[36], mP1[8], mC1[36];
	208	Transport( dS, mP, mC );
	209	p.Transport( dS1, mP1, mC1 );
	210	Double_t dx = mP[0]-mP1[0];
	211	Double_t dy = mP[1]-mP1[1];
	212	return TMath::Sqrt(dxdx+dydy);
	213	}
	214
	215	Double_t AliKFParticle::GetDeviationFromParticleXY( const AliKFParticle &p ) const
	216	{
	217	//* Calculate sqrt(Chi2/ndf) deviation from other particle
	218
	219	Double_t dS, dS1;
	220	GetDStoParticleXY( p, dS, dS1 );
	221	Double_t mP1[8], mC1[36];
	222	p.Transport( dS1, mP1, mC1 );
616ffc76	223
e7b09c95	224	Double_t d[2]={ fP[0]-mP1[0], fP[1]-mP1[1] };
616ffc76	225
e7b09c95	226	Double_t sigmaS = .1+10.TMath::Sqrt( (d[0]d[0]+d[1]*d[1] )/
e7b09c95	227	(mP1[3]mP1[3]+mP1[4]mP1[4] ) );
616ffc76	228
e7b09c95	229	Double_t h[2] = { mP1[3]sigmaS, mP1[4]sigmaS };
616ffc76	230
e7b09c95	231	mC1[0] +=h[0]*h[0];
	232	mC1[1] +=h[1]*h[0];
	233	mC1[2] +=h[1]*h[1];
	234
	235	return GetDeviationFromVertexXY( mP1, mC1 )*TMath::Sqrt(2./1.);
	236	}
	237
	238
446ce366	239	Double_t AliKFParticle::GetDeviationFromVertexXY( const Double_t vtx[], const Double_t Cv[] ) const
e7b09c95	240	{
	241	//* Calculate sqrt(Chi2/ndf) deviation from vertex
	242	//* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix
	243
446ce366	244	Double_t val, err;
	245	Bool_t problem = GetDistanceFromVertexXY( vtx, Cv, val, err );
	246	if( problem \|\| err<1.e-20 ) return 1.e4;
	247	else return val/err;
e7b09c95	248	}
	249
	250
706952f5	251	Double_t AliKFParticle::GetDeviationFromVertexXY( const AliKFParticle &Vtx ) const
e7b09c95	252	{
	253	//* Calculate sqrt(Chi2/ndf) deviation from vertex
	254	//* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix
	255
	256	return GetDeviationFromVertexXY( Vtx.fP, Vtx.fC );
	257	}
	258
706952f5	259	Double_t AliKFParticle::GetDeviationFromVertexXY( const AliVVertex &Vtx ) const
e7b09c95	260	{
	261	//* Calculate sqrt(Chi2/ndf) deviation from vertex
	262	//* v = [xyz], Cv=[Cxx,Cxy,Cyy,Cxz,Cyz,Czz]-covariance matrix
	263
	264	AliKFParticle v(Vtx);
	265	return GetDeviationFromVertexXY( v.fP, v.fC );
	266	}
	267
e7b09c95	268	Double_t AliKFParticle::GetAngle ( const AliKFParticle &p ) const
	269	{
	270	//* Calculate the opening angle between two particles
	271
	272	Double_t dS, dS1;
	273	GetDStoParticle( p, dS, dS1 );
	274	Double_t mP[8], mC[36], mP1[8], mC1[36];
	275	Transport( dS, mP, mC );
	276	p.Transport( dS1, mP1, mC1 );
	277	Double_t n = TMath::Sqrt( mP[3]mP[3] + mP[4]mP[4] + mP[5]*mP[5] );
	278	Double_t n1= TMath::Sqrt( mP1[3]mP1[3] + mP1[4]mP1[4] + mP1[5]*mP1[5] );
	279	n*=n1;
	280	Double_t a = 0;
	281	if( n>1.e-8 ) a = ( mP[3]mP1[3] + mP[4]mP1[4] + mP[5]*mP1[5] )/n;
	282	if (TMath::Abs(a)<1.) a = TMath::ACos(a);
	283	else a = (a>=0) ?0 :TMath::Pi();
	284	return a;
	285	}
	286
	287	Double_t AliKFParticle::GetAngleXY( const AliKFParticle &p ) const
	288	{
	289	//* Calculate the opening angle between two particles in XY plane
	290
	291	Double_t dS, dS1;
	292	GetDStoParticleXY( p, dS, dS1 );
	293	Double_t mP[8], mC[36], mP1[8], mC1[36];
	294	Transport( dS, mP, mC );
	295	p.Transport( dS1, mP1, mC1 );
	296	Double_t n = TMath::Sqrt( mP[3]mP[3] + mP[4]mP[4] );
	297	Double_t n1= TMath::Sqrt( mP1[3]mP1[3] + mP1[4]mP1[4] );
	298	n*=n1;
	299	Double_t a = 0;
	300	if( n>1.e-8 ) a = ( mP[3]mP1[3] + mP[4]mP1[4] )/n;
	301	if (TMath::Abs(a)<1.) a = TMath::ACos(a);
	302	else a = (a>=0) ?0 :TMath::Pi();
	303	return a;
	304	}
	305
	306	Double_t AliKFParticle::GetAngleRZ( const AliKFParticle &p ) const
	307	{
	308	//* Calculate the opening angle between two particles in RZ plane
616ffc76	309
e7b09c95	310	Double_t dS, dS1;
	311	GetDStoParticle( p, dS, dS1 );
	312	Double_t mP[8], mC[36], mP1[8], mC1[36];
	313	Transport( dS, mP, mC );
	314	p.Transport( dS1, mP1, mC1 );
	315	Double_t nr = TMath::Sqrt( mP[3]mP[3] + mP[4]mP[4] );
	316	Double_t n1r= TMath::Sqrt( mP1[3]mP1[3] + mP1[4]mP1[4] );
	317	Double_t n = TMath::Sqrt( nrnr + mP[5]mP[5] );
	318	Double_t n1= TMath::Sqrt( n1rn1r + mP1[5]mP1[5] );
	319	n*=n1;
	320	Double_t a = 0;
	321	if( n>1.e-8 ) a = ( nrn1r +mP[5]mP1[5])/n;
	322	if (TMath::Abs(a)<1.) a = TMath::ACos(a);
	323	else a = (a>=0) ?0 :TMath::Pi();
	324	return a;
616ffc76	325	}
706952f5	326
	327
	328	/*
	329
	330	#include "AliExternalTrackParam.h"
	331
	332	void AliKFParticle::GetDStoParticleALICE( const AliKFParticleBase &p,
	333	Double_t &DS, Double_t &DS1 )
	334	const
	335	{
	336	DS = DS1 = 0;
	337	Double_t x1, a1, x2, a2;
	338	Double_t par1[5], par2[5], cov[15];
	339	for(int i=0; i<15; i++) cov[i] = 0;
	340	cov[0] = cov[2] = cov[5] = cov[9] = cov[14] = .001;
	341
	342	GetExternalTrackParam( *this, x1, a1, par1 );
	343	GetExternalTrackParam( p, x2, a2, par2 );
	344
	345	AliExternalTrackParam t1(x1,a1, par1, cov);
	346	AliExternalTrackParam t2(x2,a2, par2, cov);
	347
	348	Double_t xe1=0, xe2=0;
	349	t1.GetDCA( &t2, -GetFieldAlice(), xe1, xe2 );
	350	t1.PropagateTo( xe1, -GetFieldAlice() );
	351	t2.PropagateTo( xe2, -GetFieldAlice() );
	352
	353	Double_t xyz1[3], xyz2[3];
	354	t1.GetXYZ( xyz1 );
	355	t2.GetXYZ( xyz2 );
	356
	357	DS = GetDStoPoint( xyz1 );
	358	DS1 = p.GetDStoPoint( xyz2 );
	359
	360	return;
	361	}
	362	*/