[u/mrichter/AliRoot.git] / RALICE / AliTrack.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/*
$Log$
Revision 1.2  1999/09/29 09:24:28  fca
Introduction of the Copyright and cvs Log

*/

///////////////////////////////////////////////////////////////////////////
// Class AliTrack
// Handling of the attributes of a reconstructed particle track.
//
// Coding example :
// ----------------
//
// Float_t a[4]={195.,1.2,-0.04,8.5};
// Ali4Vector pmu;
// pmu.SetVector(a,"car");
// AliTrack t1;
// t1.Set4Momentum(pmu);
//
// Float_t b[3]={1.2,-0.04,8.5};
// Ali3Vector p;
// p.SetVector(b,"car");
// AliTrack t2;
// t2.Set3Momentum(p);
// t2.SetCharge(0);
// t2.SetMass(1.115);
//
// t1.Info();
// t2.Info();
//
// Float_t pi=acos(-1.);
// Float_t thcms=0.2*pi; // decay theta angle in cms
// Float_t phicms=pi/4.; // decay theta angle in cms
// Float_t m1=0.938;
// Float_t m2=0.140;
// t2.Decay(m1,m2,thcms,phicms); // Track t2 decay : Lambda -> proton + pion
//
// t2.List();
//
// Int_t ndec=t2.GetNdecay();
// AliTrack* d1=t2.GetDecayTrack(1); // Access to decay track number 1
// AliTrack* d2=t2.GetDecayTrack(2); // Access to decay track number 2
//
// AliSignal s1,s2,s3,s4;
//
// .... // Code (e.g. detector readout) to fill AliSignal data
//
// AliTrack trec; // Track which will be reconstructed from signals
// trec.AddSignal(s1);
// trec.AddSignal(s3);
// trec.AddSignal(s4);
//
// Ali3Vector P;
// Float_t Q,M;
//
// ... // Code which accesses signals from trec and reconstructs
//        3-momentum P, charge Q, mass M etc...
//
// trec.Set3Momentum(P);
// trec.SetCharge(Q);
// trec.SetMass(M);
//
// Float_t r1[3]={1.6,-3.8,25.7};
// Float_t er1[3]={0.2,0.5,1.8};
// Float_t r2[3]={8.6,23.8,-6.7};
// Float_t er2[3]={0.93,1.78,0.8};
// AliPosition begin,end;
// begin.SetPosition(r1,"car");
// begin.SetPositionErrors(er1,"car");
// end.SetPosition(r2,"car");
// end.SetPositionErrors(er2,"car");
// trec.SetBeginPoint(begin);
// trec.SetEndPoint(end);
// 
// Note : All quantities are in GeV, GeV/c or GeV/c**2
//
//--- Author: Nick van Eijndhoven 10-jul-1997 UU-SAP Utrecht
//- Modified: NvE 29-oct-1999 UU-SAP Utrecht
///////////////////////////////////////////////////////////////////////////

#include "AliTrack.h"
 
ClassImp(AliTrack) // Class implementation to enable ROOT I/O
 
AliTrack::AliTrack()
{
// Default constructor
// All variables initialised to 0
 fDecays=0;
 fSignals=0;
 Reset();
}
///////////////////////////////////////////////////////////////////////////
AliTrack::~AliTrack()
{
// Destructor to delete memory allocated for decay tracks array
 if (fDecays)
 {
  fDecays->Delete();
  delete fDecays;
  fDecays=0;
 }
 if (fSignals)
 {
  fSignals->Clear();
  delete fSignals;
  fSignals=0;
 }
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::Reset()
{
// Reset all variables to 0
 fQ=0;
 fNdec=0;
 fNsig=0;
 Double_t a[4]={0,0,0,0};
 SetVector(a,"sph");
 if (fDecays)
 {
  fDecays->Delete();
  delete fDecays;
  fDecays=0;
 }
 if (fSignals)
 {
  fSignals->Clear();
  delete fSignals;
  fSignals=0;
 }
 Double_t b[3]={0,0,0};
 fBegin.SetPosition(b,"sph");
 fEnd.SetPosition(b,"sph");
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::Set3Momentum(Ali3Vector& p)
{
// Set the track parameters according to the 3-momentum p
 Set3Vector(p);
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::Set4Momentum(Ali4Vector& p)
{
// Set the track parameters according to the 4-momentum p
 Double_t E=p.GetScalar();
 Double_t dE=p.GetResultError();
 Ali3Vector pv=p.Get3Vector();
 SetVector(E,pv);
 SetScalarError(dE);
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::SetMass(Double_t m,Double_t dm)
{
// Set the particle mass
// The default value for the error dm is 0.
 Double_t inv=pow(m,2);
 Double_t dinv=fabs(2.*m*dm);
 SetInvariant(inv,dinv);
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::SetCharge(Float_t q)
{
// Set the particle charge
 fQ=q;
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::Info(TString f)
{
// Provide track information within the coordinate frame f
 Double_t m=GetMass();
 Double_t dm=GetResultError();
 cout << " *AliTrack::Info* Mass : " << m
      << " error : " << dm << " Charge : " << fQ
      << " Momentum : " << GetMomentum() << " Ntracks : " << fNdec
      << " Nsignals : " << fNsig << endl;
 Ali4Vector::Info(f); 
} 
///////////////////////////////////////////////////////////////////////////
void AliTrack::List(TString f)
{
// Provide current track and decay level 1 information within coordinate frame f

 Info(f); // Information of the current track

 // Decay products of this track
 AliTrack* td; 
 for (Int_t id=1; id<=fNdec; id++)
 {
  td=GetDecayTrack(id);
  if (td)
  {
   cout << "  ---Level 1 sec. track no. " << id << endl;
   td->Info(f); 
  }
  else
  {
   cout << " *AliTrack::List* Error : No decay track present." << endl; 
  }
 }
} 
///////////////////////////////////////////////////////////////////////////
void AliTrack::ListAll(TString f)
{
// Provide complete track and decay information within the coordinate frame f

 Info(f); // Information of the current track
 cout << " Begin-point :"; fBegin.Info(f);
 cout << " End-point   :"; fEnd.Info(f);
 for (Int_t is=1; is<=GetNsignals(); is++)
 {
  ((AliSignal*)GetSignal(is))->Info(f);
 }

 AliTrack* t=this;
 Dump(t,1,f); // Information of all decay products
}
//////////////////////////////////////////////////////////////////////////
void AliTrack::Dump(AliTrack* t,Int_t n,TString f)
{
// Recursively provide the info of all decay levels of this track
 AliTrack* td; 
 for (Int_t id=1; id<=t->GetNdecay(); id++)
 {
  td=t->GetDecayTrack(id);
  if (td)
  {
   cout << "  ---Level " << n << " sec. track no. " << id << endl;
   td->Info(f); 
   for (Int_t is=1; is<=td->GetNsignals(); is++)
   {
    ((AliSignal*)td->GetSignal(is))->Info(f);
   }

   // Go for next decay level of this decay track recursively
   Dump(td,n+1,f);
  }
  else
  {
   cout << " *AliTrack::Dump* Error : No decay track present." << endl; 
  }
 }
} 
//////////////////////////////////////////////////////////////////////////
Double_t AliTrack::GetMomentum()
{
// Provide the value of the track 3-momentum.
// The error can be obtained by invoking GetResultError() after
// invokation of GetMomentum().

// Ali3Vector p=Get3Vector();
// return sqrt(p.Dot(p));
 Double_t norm=fV.GetNorm();
 return norm;
}
///////////////////////////////////////////////////////////////////////////
Ali3Vector AliTrack::Get3Momentum()
{
// Provide the track 3-momentum
 return (Ali3Vector)Get3Vector();
}
///////////////////////////////////////////////////////////////////////////
Double_t AliTrack::GetMass()
{
// Provide the particle mass.
// The error can be obtained by invoking GetResultError() after
// invokation of GetMass().
 Double_t inv=GetInvariant();
 Double_t dinv=GetResultError();
 Double_t dm=0;
 if (inv >= 0)
 {
 Double_t m=sqrt(inv);
 if (m) dm=dinv/(2.*m);
 fDresult=dm;
 return m;
 }
 else
 {
  cout << "*AliTrack::GetMass* Unphysical situation m**2 = " << inv << endl;
  cout << " Value 0 will be returned." << endl;
  fDresult=dm;
  return 0;
 }
}
///////////////////////////////////////////////////////////////////////////
Float_t AliTrack::GetCharge()
{
// Provide the particle charge
 return fQ;
}
///////////////////////////////////////////////////////////////////////////
Double_t AliTrack::GetEnergy()
{
// Provide the particle's energy.
// The error can be obtained by invoking GetResultError() after
// invokation of GetEnergy().
 Double_t E=GetScalar();
 if (E>0)
 {
  return E;
 }
 else
 {
  cout << "*AliTrack::GetEnergy* Unphysical situation E = " << E << endl;
  cout << " Value 0 will be returned." << endl;
  return 0;
 }
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::Decay(Double_t m1,Double_t m2,Double_t thcms,Double_t phicms)
{
// Perform 2-body decay of current track
// m1     : mass of decay product 1
// m2     : mass of decay product 2
// thcms  : cms theta decay angle (in rad.) of m1
// phicms : cms phi decay angle (in rad.) of m1
 
 fNdec=2; // it's a 2-body decay

 Double_t M=GetMass();
 
// Compute the 4-momenta of the decay products in the cms
// Note : p2=p1=pnorm for a 2-body decay
 Double_t e1=0;
 if (M) e1=((M*M)+(m1*m1)-(m2*m2))/(2.*M);
 Double_t e2=0;
 if (M) e2=((M*M)+(m2*m2)-(m1*m1))/(2.*M);
 Double_t pnorm=(e1*e1)-(m1*m1);
 if (pnorm>0.)
 {
  pnorm=sqrt(pnorm);
 }
 else
 {
  pnorm=0;
 }
 
 Double_t a[3];
 a[0]=pnorm;
 a[1]=thcms;
 a[2]=phicms;
 Ali3Vector p;
 p.SetVector(a,"sph");

 Ali4Vector pprim1;
 pprim1.SetVector(e1,p);
 pprim1.SetInvariant(m1*m1);

 Ali4Vector pprim2;
 p*=-1;
 pprim2.SetVector(e2,p);
 pprim2.SetInvariant(m2*m2);

 // Determine boost parameters from the parent particle
 Double_t E=GetEnergy();
 p=Get3Vector();
 Ali4Vector pmu;
 pmu.SetVector(E,p);

 AliBoost q;
 q.Set4Momentum(pmu);
 
 Ali4Vector p1=q.Inverse(pprim1); // Boost decay product 1
 Ali4Vector p2=q.Inverse(pprim2); // Boost decay product 2
 
 // Enter the boosted data into the decay tracks array
 if (fDecays)
 {
  fDecays->Delete();
  delete fDecays;
 }
 fDecays=new TObjArray();

 fDecays->Add(new AliTrack);
 ((AliTrack*)fDecays->At(0))->Set4Momentum(p1);
 ((AliTrack*)fDecays->At(0))->SetMass(m1);
 fDecays->Add(new AliTrack);
 ((AliTrack*)fDecays->At(1))->Set4Momentum(p2);
 ((AliTrack*)fDecays->At(1))->SetMass(m2);
}
///////////////////////////////////////////////////////////////////////////
Int_t AliTrack::GetNdecay()
{
// Provide the number of decay produced tracks
 return fNdec;
}
///////////////////////////////////////////////////////////////////////////
AliTrack* AliTrack::GetDecayTrack(Int_t j)
{
// Provide decay produced track number j
// Note : j=1 denotes the first decay track
 if ((j >= 1) && (j <= fNdec))
 {
  return (AliTrack*)fDecays->At(j-1);
 }
 else
 {
  cout << " *AliTrack* decay track number : " << j << " out of range." << endl;
  cout << " -- Decay track number 1 (if any) returned." << endl;
  return (AliTrack*)fDecays->At(0);
 }
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::AddSignal(AliSignal& s)
{
// Relate an AliSignal object to this track.
 if (!fSignals) fSignals=new TObjArray();
 fNsig++;
 fSignals->Add(&s);
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::RemoveSignal(AliSignal& s)
{
// Remove related AliSignal object to this track.
 if (fSignals)
 {
  AliSignal* test=(AliSignal*)fSignals->Remove(&s);
  if (test)
  {
   fNsig--;
   fSignals->Compress();
  }
 }
}
///////////////////////////////////////////////////////////////////////////
Int_t AliTrack::GetNsignals()
{
// Provide the number of related AliSignals.
 return fNsig;
}
///////////////////////////////////////////////////////////////////////////
AliSignal* AliTrack::GetSignal(Int_t j)
{
// Provide the related AliSignal number j.
// Note : j=1 denotes the first signal.
 if ((j >= 1) && (j <= fNsig))
 {
  return (AliSignal*)fSignals->At(j-1);
 }
 else
 {
  cout << " *AliTrack* signal number : " << j << " out of range." << endl;
  cout << " -- Signal number 1 (if any) returned." << endl;
  return (AliSignal*)fDecays->At(0);
 }
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::SetBeginPoint(AliPosition p)
{
// Store the position of the track begin-point.
 fBegin=p;
}
///////////////////////////////////////////////////////////////////////////
AliPosition AliTrack::GetBeginPoint()
{
// Provide the position of the track begin-point.
 return fBegin;
}
///////////////////////////////////////////////////////////////////////////
void AliTrack::SetEndPoint(AliPosition p)
{
// Store the position of the track end-point.
 fEnd=p;
}
///////////////////////////////////////////////////////////////////////////
AliPosition AliTrack::GetEndPoint()
{
// Provide the position of the track end-point.
 return fEnd;
}
///////////////////////////////////////////////////////////////////////////
Commit	Line	Data
4c039060	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	7	* Permission to use, copy, modify and distribute this software and its *
	8	* documentation strictly for non-commercial purposes is hereby granted *
	9	* without fee, provided that the above copyright notice appears in all *
	10	* copies and that both the copyright notice and this permission notice *
	11	* appear in the supporting documentation. The authors make no claims *
	12	* about the suitability of this software for any purpose. It is *
	13	* provided "as is" without express or implied warranty. *
	14	**************************************************************************/
	15
	16	/*
	17	$Log$
959fbac5	18	Revision 1.2 1999/09/29 09:24:28 fca
	19	Introduction of the Copyright and cvs Log
	20
4c039060	21	*/
4c039060	22
959fbac5	23	///////////////////////////////////////////////////////////////////////////
	24	// Class AliTrack
	25	// Handling of the attributes of a reconstructed particle track.
	26	//
	27	// Coding example :
	28	// ----------------
	29	//
	30	// Float_t a[4]={195.,1.2,-0.04,8.5};
	31	// Ali4Vector pmu;
	32	// pmu.SetVector(a,"car");
	33	// AliTrack t1;
	34	// t1.Set4Momentum(pmu);
	35	//
	36	// Float_t b[3]={1.2,-0.04,8.5};
	37	// Ali3Vector p;
	38	// p.SetVector(b,"car");
	39	// AliTrack t2;
	40	// t2.Set3Momentum(p);
	41	// t2.SetCharge(0);
	42	// t2.SetMass(1.115);
	43	//
	44	// t1.Info();
	45	// t2.Info();
	46	//
	47	// Float_t pi=acos(-1.);
	48	// Float_t thcms=0.2*pi; // decay theta angle in cms
	49	// Float_t phicms=pi/4.; // decay theta angle in cms
	50	// Float_t m1=0.938;
	51	// Float_t m2=0.140;
	52	// t2.Decay(m1,m2,thcms,phicms); // Track t2 decay : Lambda -> proton + pion
	53	//
	54	// t2.List();
	55	//
	56	// Int_t ndec=t2.GetNdecay();
	57	// AliTrack* d1=t2.GetDecayTrack(1); // Access to decay track number 1
	58	// AliTrack* d2=t2.GetDecayTrack(2); // Access to decay track number 2
	59	//
	60	// AliSignal s1,s2,s3,s4;
	61	//
	62	// .... // Code (e.g. detector readout) to fill AliSignal data
	63	//
	64	// AliTrack trec; // Track which will be reconstructed from signals
	65	// trec.AddSignal(s1);
	66	// trec.AddSignal(s3);
	67	// trec.AddSignal(s4);
	68	//
	69	// Ali3Vector P;
	70	// Float_t Q,M;
	71	//
	72	// ... // Code which accesses signals from trec and reconstructs
	73	// 3-momentum P, charge Q, mass M etc...
	74	//
	75	// trec.Set3Momentum(P);
	76	// trec.SetCharge(Q);
	77	// trec.SetMass(M);
	78	//
	79	// Float_t r1[3]={1.6,-3.8,25.7};
	80	// Float_t er1[3]={0.2,0.5,1.8};
	81	// Float_t r2[3]={8.6,23.8,-6.7};
	82	// Float_t er2[3]={0.93,1.78,0.8};
	83	// AliPosition begin,end;
	84	// begin.SetPosition(r1,"car");
	85	// begin.SetPositionErrors(er1,"car");
	86	// end.SetPosition(r2,"car");
87	// end.SetPositionErrors(er2,"car");
88	// trec.SetBeginPoint(begin);
89	// trec.SetEndPoint(end);
90	//
91	// Note : All quantities are in GeV, GeV/c or GeV/c**2
92	//
93	//--- Author: Nick van Eijndhoven 10-jul-1997 UU-SAP Utrecht
94	//- Modified: NvE 29-oct-1999 UU-SAP Utrecht
95	///////////////////////////////////////////////////////////////////////////
96
d88f97cc	97	#include "AliTrack.h"
	98
	99	ClassImp(AliTrack) // Class implementation to enable ROOT I/O
	100
	101	AliTrack::AliTrack()
	102	{
	103	// Default constructor
	104	// All variables initialised to 0
	105	fDecays=0;
959fbac5	106	fSignals=0;
d88f97cc	107	Reset();
	108	}
	109	///////////////////////////////////////////////////////////////////////////
	110	AliTrack::~AliTrack()
	111	{
	112	// Destructor to delete memory allocated for decay tracks array
	113	if (fDecays)
	114	{
	115	fDecays->Delete();
	116	delete fDecays;
	117	fDecays=0;
	118	}
959fbac5	119	if (fSignals)
	120	{
	121	fSignals->Clear();
	122	delete fSignals;
	123	fSignals=0;
	124	}
d88f97cc	125	}
	126	///////////////////////////////////////////////////////////////////////////
	127	void AliTrack::Reset()
	128	{
	129	// Reset all variables to 0
d88f97cc	130	fQ=0;
d88f97cc	131	fNdec=0;
959fbac5	132	fNsig=0;
d88f97cc	133	Double_t a[4]={0,0,0,0};
	134	SetVector(a,"sph");
	135	if (fDecays)
	136	{
	137	fDecays->Delete();
	138	delete fDecays;
	139	fDecays=0;
	140	}
959fbac5	141	if (fSignals)
	142	{
	143	fSignals->Clear();
	144	delete fSignals;
	145	fSignals=0;
	146	}
	147	Double_t b[3]={0,0,0};
	148	fBegin.SetPosition(b,"sph");
	149	fEnd.SetPosition(b,"sph");
d88f97cc	150	}
	151	///////////////////////////////////////////////////////////////////////////
	152	void AliTrack::Set3Momentum(Ali3Vector& p)
	153	{
	154	// Set the track parameters according to the 3-momentum p
959fbac5	155	Set3Vector(p);
d88f97cc	156	}
	157	///////////////////////////////////////////////////////////////////////////
	158	void AliTrack::Set4Momentum(Ali4Vector& p)
	159	{
	160	// Set the track parameters according to the 4-momentum p
	161	Double_t E=p.GetScalar();
959fbac5	162	Double_t dE=p.GetResultError();
d88f97cc	163	Ali3Vector pv=p.Get3Vector();
d88f97cc	164	SetVector(E,pv);
959fbac5	165	SetScalarError(dE);
d88f97cc	166	}
d88f97cc	167	///////////////////////////////////////////////////////////////////////////
959fbac5	168	void AliTrack::SetMass(Double_t m,Double_t dm)
d88f97cc	169	{
d88f97cc	170	// Set the particle mass
959fbac5	171	// The default value for the error dm is 0.
	172	Double_t inv=pow(m,2);
	173	Double_t dinv=fabs(2.mdm);
	174	SetInvariant(inv,dinv);
d88f97cc	175	}
	176	///////////////////////////////////////////////////////////////////////////
	177	void AliTrack::SetCharge(Float_t q)
	178	{
	179	// Set the particle charge
	180	fQ=q;
	181	}
	182	///////////////////////////////////////////////////////////////////////////
	183	void AliTrack::Info(TString f)
	184	{
	185	// Provide track information within the coordinate frame f
959fbac5	186	Double_t m=GetMass();
	187	Double_t dm=GetResultError();
	188	cout << " AliTrack::Info Mass : " << m
	189	<< " error : " << dm << " Charge : " << fQ
	190	<< " Momentum : " << GetMomentum() << " Ntracks : " << fNdec
	191	<< " Nsignals : " << fNsig << endl;
d88f97cc	192	Ali4Vector::Info(f);
	193	}
	194	///////////////////////////////////////////////////////////////////////////
	195	void AliTrack::List(TString f)
	196	{
	197	// Provide current track and decay level 1 information within coordinate frame f
	198
	199	Info(f); // Information of the current track
	200
	201	// Decay products of this track
	202	AliTrack* td;
	203	for (Int_t id=1; id<=fNdec; id++)
	204	{
	205	td=GetDecayTrack(id);
	206	if (td)
	207	{
	208	cout << " ---Level 1 sec. track no. " << id << endl;
d88f97cc	209	td->Info(f);
	210	}
	211	else
	212	{
	213	cout << " AliTrack::List Error : No decay track present." << endl;
	214	}
	215	}
	216	}
	217	///////////////////////////////////////////////////////////////////////////
	218	void AliTrack::ListAll(TString f)
	219	{
	220	// Provide complete track and decay information within the coordinate frame f
	221
	222	Info(f); // Information of the current track
959fbac5	223	cout << " Begin-point :"; fBegin.Info(f);
	224	cout << " End-point :"; fEnd.Info(f);
	225	for (Int_t is=1; is<=GetNsignals(); is++)
	226	{
	227	((AliSignal*)GetSignal(is))->Info(f);
	228	}
d88f97cc	229
	230	AliTrack* t=this;
	231	Dump(t,1,f); // Information of all decay products
	232	}
	233	//////////////////////////////////////////////////////////////////////////
	234	void AliTrack::Dump(AliTrack* t,Int_t n,TString f)
	235	{
	236	// Recursively provide the info of all decay levels of this track
	237	AliTrack* td;
	238	for (Int_t id=1; id<=t->GetNdecay(); id++)
	239	{
	240	td=t->GetDecayTrack(id);
	241	if (td)
	242	{
	243	cout << " ---Level " << n << " sec. track no. " << id << endl;
d88f97cc	244	td->Info(f);
959fbac5	245	for (Int_t is=1; is<=td->GetNsignals(); is++)
	246	{
	247	((AliSignal*)td->GetSignal(is))->Info(f);
	248	}
d88f97cc	249
	250	// Go for next decay level of this decay track recursively
	251	Dump(td,n+1,f);
	252	}
	253	else
	254	{
	255	cout << " AliTrack::Dump Error : No decay track present." << endl;
	256	}
	257	}
	258	}
	259	//////////////////////////////////////////////////////////////////////////
	260	Double_t AliTrack::GetMomentum()
	261	{
959fbac5	262	// Provide the value of the track 3-momentum.
	263	// The error can be obtained by invoking GetResultError() after
	264	// invokation of GetMomentum().
	265
	266	// Ali3Vector p=Get3Vector();
	267	// return sqrt(p.Dot(p));
	268	Double_t norm=fV.GetNorm();
	269	return norm;
d88f97cc	270	}
	271	///////////////////////////////////////////////////////////////////////////
	272	Ali3Vector AliTrack::Get3Momentum()
	273	{
	274	// Provide the track 3-momentum
	275	return (Ali3Vector)Get3Vector();
	276	}
	277	///////////////////////////////////////////////////////////////////////////
	278	Double_t AliTrack::GetMass()
	279	{
959fbac5	280	// Provide the particle mass.
	281	// The error can be obtained by invoking GetResultError() after
	282	// invokation of GetMass().
	283	Double_t inv=GetInvariant();
	284	Double_t dinv=GetResultError();
	285	Double_t dm=0;
	286	if (inv >= 0)
	287	{
	288	Double_t m=sqrt(inv);
	289	if (m) dm=dinv/(2.*m);
	290	fDresult=dm;
	291	return m;
	292	}
	293	else
	294	{
	295	cout << "AliTrack::GetMass Unphysical situation m**2 = " << inv << endl;
	296	cout << " Value 0 will be returned." << endl;
	297	fDresult=dm;
	298	return 0;
	299	}
d88f97cc	300	}
	301	///////////////////////////////////////////////////////////////////////////
	302	Float_t AliTrack::GetCharge()
	303	{
	304	// Provide the particle charge
	305	return fQ;
	306	}
	307	///////////////////////////////////////////////////////////////////////////
	308	Double_t AliTrack::GetEnergy()
	309	{
959fbac5	310	// Provide the particle's energy.
	311	// The error can be obtained by invoking GetResultError() after
	312	// invokation of GetEnergy().
	313	Double_t E=GetScalar();
	314	if (E>0)
	315	{
	316	return E;
	317	}
	318	else
	319	{
	320	cout << "AliTrack::GetEnergy Unphysical situation E = " << E << endl;
	321	cout << " Value 0 will be returned." << endl;
	322	return 0;
	323	}
d88f97cc	324	}
	325	///////////////////////////////////////////////////////////////////////////
	326	void AliTrack::Decay(Double_t m1,Double_t m2,Double_t thcms,Double_t phicms)
	327	{
	328	// Perform 2-body decay of current track
	329	// m1 : mass of decay product 1
	330	// m2 : mass of decay product 2
	331	// thcms : cms theta decay angle (in rad.) of m1
	332	// phicms : cms phi decay angle (in rad.) of m1
	333
	334	fNdec=2; // it's a 2-body decay
959fbac5	335
959fbac5	336	Double_t M=GetMass();
d88f97cc	337
	338	// Compute the 4-momenta of the decay products in the cms
	339	// Note : p2=p1=pnorm for a 2-body decay
959fbac5	340	Double_t e1=0;
	341	if (M) e1=((MM)+(m1m1)-(m2m2))/(2.M);
	342	Double_t e2=0;
	343	if (M) e2=((MM)+(m2m2)-(m1m1))/(2.M);
d88f97cc	344	Double_t pnorm=(e1e1)-(m1m1);
	345	if (pnorm>0.)
	346	{
	347	pnorm=sqrt(pnorm);
	348	}
	349	else
	350	{
	351	pnorm=0;
	352	}
	353
	354	Double_t a[3];
	355	a[0]=pnorm;
	356	a[1]=thcms;
	357	a[2]=phicms;
	358	Ali3Vector p;
	359	p.SetVector(a,"sph");
	360
	361	Ali4Vector pprim1;
	362	pprim1.SetVector(e1,p);
959fbac5	363	pprim1.SetInvariant(m1*m1);
d88f97cc	364
	365	Ali4Vector pprim2;
	366	p*=-1;
	367	pprim2.SetVector(e2,p);
959fbac5	368	pprim2.SetInvariant(m2*m2);
d88f97cc	369
d88f97cc	370	// Determine boost parameters from the parent particle
959fbac5	371	Double_t E=GetEnergy();
d88f97cc	372	p=Get3Vector();
	373	Ali4Vector pmu;
	374	pmu.SetVector(E,p);
	375
	376	AliBoost q;
	377	q.Set4Momentum(pmu);
	378
	379	Ali4Vector p1=q.Inverse(pprim1); // Boost decay product 1
	380	Ali4Vector p2=q.Inverse(pprim2); // Boost decay product 2
	381
	382	// Enter the boosted data into the decay tracks array
	383	if (fDecays)
	384	{
	385	fDecays->Delete();
	386	delete fDecays;
	387	}
	388	fDecays=new TObjArray();
	389
	390	fDecays->Add(new AliTrack);
	391	((AliTrack*)fDecays->At(0))->Set4Momentum(p1);
959fbac5	392	((AliTrack*)fDecays->At(0))->SetMass(m1);
d88f97cc	393	fDecays->Add(new AliTrack);
d88f97cc	394	((AliTrack*)fDecays->At(1))->Set4Momentum(p2);
d88f97cc	395	((AliTrack*)fDecays->At(1))->SetMass(m2);
	396	}
	397	///////////////////////////////////////////////////////////////////////////
	398	Int_t AliTrack::GetNdecay()
	399	{
	400	// Provide the number of decay produced tracks
	401	return fNdec;
	402	}
	403	///////////////////////////////////////////////////////////////////////////
	404	AliTrack* AliTrack::GetDecayTrack(Int_t j)
	405	{
	406	// Provide decay produced track number j
	407	// Note : j=1 denotes the first decay track
	408	if ((j >= 1) && (j <= fNdec))
	409	{
	410	return (AliTrack*)fDecays->At(j-1);
	411	}
	412	else
	413	{
	414	cout << " AliTrack decay track number : " << j << " out of range." << endl;
	415	cout << " -- Decay track number 1 (if any) returned." << endl;
	416	return (AliTrack*)fDecays->At(0);
	417	}
	418	}
	419	///////////////////////////////////////////////////////////////////////////
959fbac5	420	void AliTrack::AddSignal(AliSignal& s)
	421	{
	422	// Relate an AliSignal object to this track.
	423	if (!fSignals) fSignals=new TObjArray();
	424	fNsig++;
	425	fSignals->Add(&s);
	426	}
	427	///////////////////////////////////////////////////////////////////////////
	428	void AliTrack::RemoveSignal(AliSignal& s)
	429	{
	430	// Remove related AliSignal object to this track.
	431	if (fSignals)
	432	{
	433	AliSignal* test=(AliSignal*)fSignals->Remove(&s);
	434	if (test)
	435	{
	436	fNsig--;
	437	fSignals->Compress();
	438	}
	439	}
	440	}
	441	///////////////////////////////////////////////////////////////////////////
	442	Int_t AliTrack::GetNsignals()
	443	{
	444	// Provide the number of related AliSignals.
	445	return fNsig;
	446	}
	447	///////////////////////////////////////////////////////////////////////////
	448	AliSignal* AliTrack::GetSignal(Int_t j)
	449	{
	450	// Provide the related AliSignal number j.
	451	// Note : j=1 denotes the first signal.
	452	if ((j >= 1) && (j <= fNsig))
	453	{
	454	return (AliSignal*)fSignals->At(j-1);
	455	}
	456	else
	457	{
	458	cout << " AliTrack signal number : " << j << " out of range." << endl;
	459	cout << " -- Signal number 1 (if any) returned." << endl;
	460	return (AliSignal*)fDecays->At(0);
	461	}
	462	}
	463	///////////////////////////////////////////////////////////////////////////
	464	void AliTrack::SetBeginPoint(AliPosition p)
	465	{
	466	// Store the position of the track begin-point.
	467	fBegin=p;
	468	}
	469	///////////////////////////////////////////////////////////////////////////
	470	AliPosition AliTrack::GetBeginPoint()
	471	{
	472	// Provide the position of the track begin-point.
	473	return fBegin;
	474	}
	475	///////////////////////////////////////////////////////////////////////////
	476	void AliTrack::SetEndPoint(AliPosition p)
	477	{
	478	// Store the position of the track end-point.
	479	fEnd=p;
	480	}
	481	///////////////////////////////////////////////////////////////////////////
	482	AliPosition AliTrack::GetEndPoint()
	483	{
484	// Provide the position of the track end-point.
485	return fEnd;
486	}
487	///////////////////////////////////////////////////////////////////////////