[u/mrichter/AliRoot.git] / HBTAN / AliHBTCrab.cxx

#include "AliHBTCrab.h"
//______________________________________________________________________
/////////////////////////////////////////////////////////////////////////
//                                                                     //
// AliRoot wrapper to CRAB                                             //
// taken from http://www.nscl.msu.edu/~pratt/freecodes/crab/home.html  //
// written by Scott Pratt                                              //
//                                                                     //
//                                                                     //
/////////////////////////////////////////////////////////////////////////
 
#include "AliHBTPair.h"

#include <TMath.h>
#include <TPDGCode.h>

#include "volya_complex.h"

//#include <complex>
//using namespace std;
AliHBTCrab* AliHBTCrab::fgCrab = 0x0;

const Double_t AliHBTCrab::fgkWcons = 1./0.1973;
const Double_t AliHBTCrab::fgkROOT2=1.41421356237309504880;
#ifdef __DECCXX
const complex AliHBTCrab::fgkCI(0.0,1.0);
#else
const double_complex AliHBTCrab::fgkCI(0.0,1.0);
#endif

/************************************************************/

AliHBTCrab* AliHBTCrab::Instance()
{
// returns instance of class
 if (fgCrab == 0x0)
  {
    fgCrab = new AliHBTCrab();
  }
 return fgCrab;
}
//===================================================================

void AliHBTCrab::Set()
{
//sets this as weighitng class
 Info("Set","Setting CRAB as Weighing Class");
 
 if ( fgWeights == 0x0 )  
  {
    fgWeights = AliHBTCrab::Instance();
    return;
  }  
 if ( fgWeights == AliHBTCrab::Instance() ) return;
 delete fgWeights;
 fgWeights = AliHBTCrab::Instance();
}
//===================================================================

AliHBTCrab::AliHBTCrab():
fBreitWigner(kFALSE),
fReducedMom(kTRUE),
fMaxMomentum(100.0)
{
  //ctor
}
//===================================================================
void AliHBTCrab::Init(Int_t pid1,Int_t pid2)
{
  fMass1 = TDatabasePDG::Instance()->GetParticle(pid1)->Mass();
  fMass2 = TDatabasePDG::Instance()->GetParticle(pid2)->Mass();
  fInteractionWsym = 1.0;
  fInteractionWanti = 0.0;
  fInteractionWnosym = 0.0;
  fInteractionDelk  = 1.0;
  fInteractionNkmax = 100;
     
  fPid1 = pid1;   
  fPid2 = pid2;
}

Bool_t AliHBTCrab::SetConfig(const AliHBTPair* pair)
{
//returns the SetConfig
  
  Int_t pdg1 = pair->Particle1()->GetPdgCode();
  Int_t pdg2 = pair->Particle2()->GetPdgCode();
  
  if ( ( pdg1 == fPid1) && ( pdg2  == fPid2) ) return kFALSE;
  else Init (pdg1,pdg2);
  
  return kTRUE;
}
//===================================================================

Double_t AliHBTCrab::GetWeight(const AliHBTPair* partpair)
{
//returns the weight
  Double_t qred, r, qdotr, mom;
  Int_t test;
  
  SetConfig(partpair);
  
  GetComQuantities(partpair, &qred, &r, &qdotr, &mom, &test);
  if(test==0) 
   {
     Info("GetWeight","Test is 0");
   }
  Double_t corr = CorrCalc(qred,qdotr,r);
  
  return corr;
}
//===================================================================

void AliHBTCrab::GetComQuantities(const AliHBTPair* pair, 
       double *qred,double *r,double *qdotr,double *mom, int *test)
 {
//************************************
//  ALICE //

 double p1[4]; 
 double p2[4]; 
 double r1[4]; 
 double r2[4]; 
 
 static const Double_t kCmToFm = 1.e13;
// static const Double_t cmtoOneOverGeV = kCmToFm*fgkWcons;
 
 AliHBTParticle *part1 = pair->Particle1();
 AliHBTParticle *part2 = pair->Particle2();

 p1[0] = part1->Energy()*1000.0;
 p1[1] = part1->Px()*1000.0;
 p1[2] = part1->Py()*1000.0;
 p1[3] = part1->Pz()*1000.0;
 
 p2[0] = part2->Energy()*1000.0;
 p2[1] = part2->Px()*1000.0;
 p2[2] = part2->Py()*1000.0;
 p2[3] = part2->Pz()*1000.0;

 r1[0] = part1->T();
 r1[1] = part1->Vx()*kCmToFm;
 r1[2] = part1->Vy()*kCmToFm;
 r1[3] = part1->Vz()*kCmToFm;

 r2[0] = part2->T();
 r2[1] = part2->Vx()*kCmToFm;
 r2[2] = part2->Vy()*kCmToFm;
 r2[3] = part2->Vz()*kCmToFm;

//  END OF ALICE STUFF

// This code is written by Scott Pratt
// taken from http://www.nscl.msu.edu/~pratt/freecodes/crab/home.html
  int alpha;
  double kdotr;
  double momtest;
  if (fReducedMom)
   {
     momtest=4.0*fMaxMomentum*fMaxMomentum;
   }  
  else
   {
     momtest=fMaxMomentum*fMaxMomentum;
   }  
   
  double ptot2,pdotr,pp,rr;
  
  if ( part1->GetPdgCode() == part2->GetPdgCode() )
   {
    *test=1;
    *mom=-(p2[0]-p1[0])*(p2[0]-p1[0]);
    for(alpha=1;alpha<4;alpha++){
      *mom=*mom+(p2[alpha]-p1[alpha])*(p2[alpha]-p1[alpha]);
    }
   //#if ! defined MIXED_PAIRS_FOR_DENOM
   //  if(*mom>momtest){
   //    *test=0;
   //    return;
   //  }
   //#endif
    pp=(p1[0]+p2[0]);
    rr=(r2[0]-r1[0]);
    pdotr=pp*rr;
    kdotr=(p2[0]-p1[0])*rr;
    ptot2=pp*pp;
    *r=-rr*rr;
    for(alpha=1;alpha<4;alpha++){
      pp=(p1[alpha]+p2[alpha]);
      rr=(r2[alpha]-r1[alpha]);
      pdotr=pdotr-pp*rr;
      kdotr=kdotr-(p2[alpha]-p1[alpha])*rr;
      ptot2=ptot2-pp*pp;
      *r=*r+rr*rr;
    }
    *mom=sqrt(*mom);
    *qred=0.5**mom;

    if (fReducedMom)
     {
      *mom=*qred;
     } 

    *qdotr=0.5*kdotr;
    *r=sqrt(*r+pdotr*pdotr/ptot2);
   }  
  else //identical
  {
  //  const double  kdotp=fMass2*fMass2-fMass1*fMass1;
   const double  kdotp = part2->GetMass()*part2->GetMass()- part1->GetMass()*part1->GetMass();
   *test=1;
   *mom=-(p2[0]-p1[0])*(p2[0]-p1[0]);
   ptot2=(p1[0]+p2[0])*(p1[0]+p2[0]);
   for(alpha=1;alpha<4;alpha++){
     *mom=*mom+(p2[alpha]-p1[alpha])*(p2[alpha]-p1[alpha]);
     ptot2=ptot2-(p1[alpha]+p2[alpha])*(p1[alpha]+p2[alpha]);
   }
   *mom=*mom+kdotp*kdotp/ptot2;
  //#if ! defined MIXED_PAIRS_FOR_DENOM
  //  if(*mom>momtest){
  //    *test=0;
  //    return;
  //  }
  //#endif
   pp=(p1[0]+p2[0]);
   rr=(r2[0]-r1[0]);
   pdotr=pp*rr;
   kdotr=(p2[0]-p1[0])*rr;
   *r=-rr*rr;
   for(alpha=1;alpha<4;alpha++){
     pp=(p1[alpha]+p2[alpha]);
     rr=(r2[alpha]-r1[alpha]);
     pdotr=pdotr-pp*rr;
     kdotr=kdotr-(p2[alpha]-p1[alpha])*rr;
     *r=*r+rr*rr;
   }
   kdotr=(-kdotr+kdotp*pdotr/ptot2);
   *mom=sqrt(*mom);
   *qred=0.5**mom;

   if (fReducedMom)
    {
     *mom=*qred;
    } 

   *qdotr=0.5*kdotr;
   *r=sqrt(*r+pdotr*pdotr/ptot2);
  }//not identical  

  return;
}


//===================================================================

double  AliHBTCrab::CorrCalc(double trueqred,double trueqdotr,double truer)
{
//#define REDUCED_MOM
// This code is written by Scott Pratt
// taken from http://www.nscl.msu.edu/~pratt/freecodes/crab/home.html
  double eta,arg,corr0;
//  double xx,xxprime,xxjj,p1,zk;
//  int jj,kk,ipart,ipartcount,ispin;
  int kk;
  double wsym_leftover,wanti_leftover,wnosym_leftover;
  double qred,qdotr,r;
//  const double rmass=fMass1*fMass2/(fMass1+fMass2);
#ifdef __DECCXX
  complex cphi1,cphi2,cphis,cphia;
#else
  double_complex cphi1,cphi2,cphis,cphia;
#endif

  arg=trueqdotr/197.323-2.0*TMath::Pi()*TMath::Floor(trueqdotr/(197.323*2.0*TMath::Pi()));
  cphi1=exp(fgkCI*arg);
  cphis=fgkROOT2*real(cphi1);
  cphia=fgkCI*fgkROOT2*imag(cphi1);
  corr0=real(fInteractionWsym*cphis*conj(cphis)
	     +fInteractionWanti*cphia*conj(cphia)
	     +fInteractionWnosym*cphi1*conj(cphi1));
  goto OUTSIDE_INTERACTION_RANGE;

#ifdef REDUCED_MOM
  kk=(int)TMath::Floor(trueqred/fInteractionDelk);
  qred=(0.5+kk)*fInteractionDelk;
#else
  kk=(int)TMath::Floor(2.0*trueqred/fInteractionDelk);
  qred=(0.5+kk)*fInteractionDelk/2.0;
#endif
  qdotr=trueqdotr*qred/trueqred;
  if(kk>=fInteractionNkmax){
    corr0=1.0;
    goto OUTSIDE_INTERACTION_RANGE;
  }
  r=truer;

  eta=0.0;
  arg=qdotr/197.323-2.0*TMath::Pi()*TMath::Floor(qdotr/(197.323*2.0*TMath::Pi()));
  cphi1=exp(fgkCI*arg);
  cphi2=conj(cphi1);

  cphis=(cphi1+cphi2)/fgkROOT2;
  cphia=(cphi1-cphi2)/fgkROOT2;
  corr0=0.0;
  /* If there are corrections for strong interactions, add the
     change for each partial wave.  If npartial = 0 then there
     are no strong int. corrections. */
  wsym_leftover=fInteractionWsym;
  wanti_leftover=fInteractionWanti;
  wnosym_leftover=fInteractionWnosym;

  corr0=corr0+real(wsym_leftover*cphis*conj(cphis)
		   +wanti_leftover*cphia*conj(cphia)
		   +wnosym_leftover*cphi1*conj(cphi1));
OUTSIDE_INTERACTION_RANGE:

#ifdef BREIT_WIGNER
  corr0=corr0+bwcalc(trueqred,truer);
#endif

  return corr0;
}

#ifdef __DECCXX
complex AliHBTCrab::CGamma(complex c){
#else
double_complex AliHBTCrab::CGamma(double_complex c){
#endif
  /* This calc.s gamma functions which are in the form gamma(n+i*y)
     where n is an int and y is real. */
// This code is written by Scott Pratt
// taken from http://www.nscl.msu.edu/~pratt/freecodes/crab/home.html
#ifdef __DECCXX
  complex cg,cphase;
#else
  double_complex cg,cphase;
#endif
  int mm,j;
  double x,y,phase,delp,cgmag;
  x=real(c);
  y=imag(c);
  phase=-TMath::E()*y;
  for(j=1;j<=100000;j++){
    delp=(y/(double)j)-atan(y/(double)j);
    phase=phase+delp;
    if(TMath::Abs(delp)<1E-10) goto CGamma_ESCAPE;
  }
  printf("oops not accurate enough, increase jmax\n");
CGamma_ESCAPE:
  phase=phase-2.0*TMath::Pi()*TMath::Floor(phase/(2.0*TMath::Pi()));
  cphase=exp(fgkCI*phase);
  cgmag=sqrt(TMath::Pi()*y/sinh(TMath::Pi()*y));
  mm=(int)TMath::Floor(x+0.5);
  cg=cgmag*cphase;
  if(mm<1){
    for(j=1;j<=-mm+1;j++){
      cg=cg/(1.0+(double)(-j)+fgkCI*y);
    }
  }
  if(mm>1) {
    for(j=1;j<=mm-1;j++){
      cg=cg*((double)(j)+fgkCI*y);
    }
  }
  return cg;
}
Commit	Line	Data
dd82cadc	1	#include "AliHBTCrab.h"
	2	//______________________________________________________________________
	3	/////////////////////////////////////////////////////////////////////////
	4	// //
	5	// AliRoot wrapper to CRAB //
	6	// taken from http://www.nscl.msu.edu/~pratt/freecodes/crab/home.html //
	7	// written by Scott Pratt //
	8	// //
c114f4f8	9	// //
dd82cadc	10	/////////////////////////////////////////////////////////////////////////
f93c53d8	11
dd82cadc	12	#include "AliHBTPair.h"
	13
	14	#include <TMath.h>
	15	#include <TPDGCode.h>
	16
	17	#include "volya_complex.h"
	18
	19	//#include <complex>
	20	//using namespace std;
	21	AliHBTCrab* AliHBTCrab::fgCrab = 0x0;
	22
	23	const Double_t AliHBTCrab::fgkWcons = 1./0.1973;
	24	const Double_t AliHBTCrab::fgkROOT2=1.41421356237309504880;
8882f543	25	#ifdef __DECCXX
c114f4f8	26	const complex AliHBTCrab::fgkCI(0.0,1.0);
8882f543	27	#else
c114f4f8	28	const double_complex AliHBTCrab::fgkCI(0.0,1.0);
8882f543	29	#endif
dd82cadc	30
	31	/************************************************************/
	32
	33	AliHBTCrab* AliHBTCrab::Instance()
	34	{
	35	// returns instance of class
	36	if (fgCrab == 0x0)
	37	{
	38	fgCrab = new AliHBTCrab();
	39	}
	40	return fgCrab;
	41	}
	42	//===================================================================
c114f4f8	43
dd82cadc	44	void AliHBTCrab::Set()
dd82cadc	45	{
c114f4f8	46	//sets this as weighitng class
dd82cadc	47	Info("Set","Setting CRAB as Weighing Class");
	48
	49	if ( fgWeights == 0x0 )
	50	{
	51	fgWeights = AliHBTCrab::Instance();
	52	return;
	53	}
	54	if ( fgWeights == AliHBTCrab::Instance() ) return;
	55	delete fgWeights;
	56	fgWeights = AliHBTCrab::Instance();
	57	}
	58	//===================================================================
	59
	60	AliHBTCrab::AliHBTCrab():
	61	fBreitWigner(kFALSE),
	62	fReducedMom(kTRUE),
	63	fMaxMomentum(100.0)
	64	{
	65	//ctor
	66	}
	67	//===================================================================
	68	void AliHBTCrab::Init(Int_t pid1,Int_t pid2)
	69	{
c114f4f8	70	fMass1 = TDatabasePDG::Instance()->GetParticle(pid1)->Mass();
	71	fMass2 = TDatabasePDG::Instance()->GetParticle(pid2)->Mass();
	72	fInteractionWsym = 1.0;
	73	fInteractionWanti = 0.0;
	74	fInteractionWnosym = 0.0;
	75	fInteractionDelk = 1.0;
	76	fInteractionNkmax = 100;
dd82cadc	77
	78	fPid1 = pid1;
	79	fPid2 = pid2;
dd82cadc	80	}
	81
	82	Bool_t AliHBTCrab::SetConfig(const AliHBTPair* pair)
	83	{
c114f4f8	84	//returns the SetConfig
c114f4f8	85
dd82cadc	86	Int_t pdg1 = pair->Particle1()->GetPdgCode();
	87	Int_t pdg2 = pair->Particle2()->GetPdgCode();
	88
	89	if ( ( pdg1 == fPid1) && ( pdg2 == fPid2) ) return kFALSE;
	90	else Init (pdg1,pdg2);
	91
	92	return kTRUE;
	93	}
	94	//===================================================================
	95
	96	Double_t AliHBTCrab::GetWeight(const AliHBTPair* partpair)
	97	{
c114f4f8	98	//returns the weight
dd82cadc	99	Double_t qred, r, qdotr, mom;
	100	Int_t test;
	101
	102	SetConfig(partpair);
	103
c114f4f8	104	GetComQuantities(partpair, &qred, &r, &qdotr, &mom, &test);
dd82cadc	105	if(test==0)
	106	{
	107	Info("GetWeight","Test is 0");
	108	}
c114f4f8	109	Double_t corr = CorrCalc(qred,qdotr,r);
dd82cadc	110
	111	return corr;
	112	}
	113	//===================================================================
	114
c114f4f8	115	void AliHBTCrab::GetComQuantities(const AliHBTPair* pair,
dd82cadc	116	double qred,double r,double qdotr,double mom, int *test)
	117	{
	118	//************************************
	119	// ALICE //
	120
	121	double p1[4];
	122	double p2[4];
	123	double r1[4];
	124	double r2[4];
	125
c114f4f8	126	static const Double_t kCmToFm = 1.e13;
c114f4f8	127	// static const Double_t cmtoOneOverGeV = kCmToFm*fgkWcons;
dd82cadc	128
	129	AliHBTParticle *part1 = pair->Particle1();
	130	AliHBTParticle *part2 = pair->Particle2();
	131
	132	p1[0] = part1->Energy()*1000.0;
	133	p1[1] = part1->Px()*1000.0;
	134	p1[2] = part1->Py()*1000.0;
	135	p1[3] = part1->Pz()*1000.0;
	136
	137	p2[0] = part2->Energy()*1000.0;
	138	p2[1] = part2->Px()*1000.0;
	139	p2[2] = part2->Py()*1000.0;
	140	p2[3] = part2->Pz()*1000.0;
	141
	142	r1[0] = part1->T();
c114f4f8	143	r1[1] = part1->Vx()*kCmToFm;
	144	r1[2] = part1->Vy()*kCmToFm;
	145	r1[3] = part1->Vz()*kCmToFm;
dd82cadc	146
dd82cadc	147	r2[0] = part2->T();
c114f4f8	148	r2[1] = part2->Vx()*kCmToFm;
	149	r2[2] = part2->Vy()*kCmToFm;
	150	r2[3] = part2->Vz()*kCmToFm;
dd82cadc	151
	152	// END OF ALICE STUFF
	153
	154	// This code is written by Scott Pratt
	155	// taken from http://www.nscl.msu.edu/~pratt/freecodes/crab/home.html
	156	int alpha;
	157	double kdotr;
f93c53d8	158	double momtest;
dd82cadc	159	if (fReducedMom)
dd82cadc	160	{
f93c53d8	161	momtest=4.0fMaxMomentumfMaxMomentum;
dd82cadc	162	}
	163	else
	164	{
f93c53d8	165	momtest=fMaxMomentum*fMaxMomentum;
dd82cadc	166	}
	167
	168	double ptot2,pdotr,pp,rr;
	169
	170	if ( part1->GetPdgCode() == part2->GetPdgCode() )
	171	{
	172	*test=1;
	173	mom=-(p2[0]-p1[0])(p2[0]-p1[0]);
	174	for(alpha=1;alpha<4;alpha++){
	175	mom=mom+(p2[alpha]-p1[alpha])*(p2[alpha]-p1[alpha]);
	176	}
	177	//#if ! defined MIXED_PAIRS_FOR_DENOM
	178	// if(*mom>momtest){
	179	// *test=0;
	180	// return;
	181	// }
	182	//#endif
	183	pp=(p1[0]+p2[0]);
	184	rr=(r2[0]-r1[0]);
	185	pdotr=pp*rr;
	186	kdotr=(p2[0]-p1[0])*rr;
	187	ptot2=pp*pp;
	188	r=-rrrr;
	189	for(alpha=1;alpha<4;alpha++){
	190	pp=(p1[alpha]+p2[alpha]);
	191	rr=(r2[alpha]-r1[alpha]);
	192	pdotr=pdotr-pp*rr;
	193	kdotr=kdotr-(p2[alpha]-p1[alpha])*rr;
	194	ptot2=ptot2-pp*pp;
	195	r=r+rr*rr;
	196	}
	197	mom=sqrt(mom);
	198	qred=0.5*mom;
	199
	200	if (fReducedMom)
	201	{
	202	mom=qred;
	203	}
	204
	205	qdotr=0.5kdotr;
	206	r=sqrt(r+pdotr*pdotr/ptot2);
	207	}
	208	else //identical
	209	{
c114f4f8	210	// const double kdotp=fMass2fMass2-fMass1fMass1;
dd82cadc	211	const double kdotp = part2->GetMass()part2->GetMass()- part1->GetMass()part1->GetMass();
	212	*test=1;
	213	mom=-(p2[0]-p1[0])(p2[0]-p1[0]);
	214	ptot2=(p1[0]+p2[0])*(p1[0]+p2[0]);
	215	for(alpha=1;alpha<4;alpha++){
	216	mom=mom+(p2[alpha]-p1[alpha])*(p2[alpha]-p1[alpha]);
	217	ptot2=ptot2-(p1[alpha]+p2[alpha])*(p1[alpha]+p2[alpha]);
	218	}
	219	mom=mom+kdotp*kdotp/ptot2;
	220	//#if ! defined MIXED_PAIRS_FOR_DENOM
	221	// if(*mom>momtest){
	222	// *test=0;
	223	// return;
	224	// }
	225	//#endif
	226	pp=(p1[0]+p2[0]);
	227	rr=(r2[0]-r1[0]);
	228	pdotr=pp*rr;
	229	kdotr=(p2[0]-p1[0])*rr;
	230	r=-rrrr;
	231	for(alpha=1;alpha<4;alpha++){
	232	pp=(p1[alpha]+p2[alpha]);
	233	rr=(r2[alpha]-r1[alpha]);
	234	pdotr=pdotr-pp*rr;
	235	kdotr=kdotr-(p2[alpha]-p1[alpha])*rr;
	236	r=r+rr*rr;
	237	}
	238	kdotr=(-kdotr+kdotp*pdotr/ptot2);
	239	mom=sqrt(mom);
	240	qred=0.5*mom;
	241
	242	if (fReducedMom)
	243	{
	244	mom=qred;
	245	}
	246
	247	qdotr=0.5kdotr;
	248	r=sqrt(r+pdotr*pdotr/ptot2);
	249	}//not identical
	250
	251	return;
	252	}
	253
	254
	255	//===================================================================
	256
c114f4f8	257	double AliHBTCrab::CorrCalc(double trueqred,double trueqdotr,double truer)
dd82cadc	258	{
	259	//#define REDUCED_MOM
	260	// This code is written by Scott Pratt
	261	// taken from http://www.nscl.msu.edu/~pratt/freecodes/crab/home.html
f93c53d8	262	double eta,arg,corr0;
	263	// double xx,xxprime,xxjj,p1,zk;
	264	// int jj,kk,ipart,ipartcount,ispin;
	265	int kk;
	266	double wsym_leftover,wanti_leftover,wnosym_leftover;
dd82cadc	267	double qred,qdotr,r;
c114f4f8	268	// const double rmass=fMass1*fMass2/(fMass1+fMass2);
8882f543	269	#ifdef __DECCXX
	270	complex cphi1,cphi2,cphis,cphia;
	271	#else
dd82cadc	272	double_complex cphi1,cphi2,cphis,cphia;
8882f543	273	#endif
dd82cadc	274
3294e9ff	275	arg=trueqdotr/197.323-2.0TMath::Pi()TMath::Floor(trueqdotr/(197.3232.0TMath::Pi()));
c114f4f8	276	cphi1=exp(fgkCI*arg);
dd82cadc	277	cphis=fgkROOT2*real(cphi1);
c114f4f8	278	cphia=fgkCIfgkROOT2imag(cphi1);
	279	corr0=real(fInteractionWsymcphisconj(cphis)
	280	+fInteractionWanticphiaconj(cphia)
	281	+fInteractionWnosymcphi1conj(cphi1));
dd82cadc	282	goto OUTSIDE_INTERACTION_RANGE;
	283
	284	#ifdef REDUCED_MOM
c114f4f8	285	kk=(int)TMath::Floor(trueqred/fInteractionDelk);
c114f4f8	286	qred=(0.5+kk)*fInteractionDelk;
dd82cadc	287	#else
c114f4f8	288	kk=(int)TMath::Floor(2.0*trueqred/fInteractionDelk);
c114f4f8	289	qred=(0.5+kk)*fInteractionDelk/2.0;
dd82cadc	290	#endif
dd82cadc	291	qdotr=trueqdotr*qred/trueqred;
c114f4f8	292	if(kk>=fInteractionNkmax){
dd82cadc	293	corr0=1.0;
	294	goto OUTSIDE_INTERACTION_RANGE;
	295	}
	296	r=truer;
	297
	298	eta=0.0;
3294e9ff	299	arg=qdotr/197.323-2.0TMath::Pi()TMath::Floor(qdotr/(197.3232.0TMath::Pi()));
c114f4f8	300	cphi1=exp(fgkCI*arg);
dd82cadc	301	cphi2=conj(cphi1);
	302
	303	cphis=(cphi1+cphi2)/fgkROOT2;
	304	cphia=(cphi1-cphi2)/fgkROOT2;
	305	corr0=0.0;
	306	/* If there are corrections for strong interactions, add the
	307	change for each partial wave. If npartial = 0 then there
	308	are no strong int. corrections. */
c114f4f8	309	wsym_leftover=fInteractionWsym;
	310	wanti_leftover=fInteractionWanti;
	311	wnosym_leftover=fInteractionWnosym;
dd82cadc	312
	313	corr0=corr0+real(wsym_leftovercphisconj(cphis)
	314	+wanti_leftovercphiaconj(cphia)
	315	+wnosym_leftovercphi1conj(cphi1));
	316	OUTSIDE_INTERACTION_RANGE:
	317
	318	#ifdef BREIT_WIGNER
	319	corr0=corr0+bwcalc(trueqred,truer);
	320	#endif
	321
	322	return corr0;
	323	}
	324
8882f543	325	#ifdef __DECCXX
c114f4f8	326	complex AliHBTCrab::CGamma(complex c){
8882f543	327	#else
c114f4f8	328	double_complex AliHBTCrab::CGamma(double_complex c){
8882f543	329	#endif
dd82cadc	330	/* This calc.s gamma functions which are in the form gamma(n+i*y)
	331	where n is an int and y is real. */
	332	// This code is written by Scott Pratt
	333	// taken from http://www.nscl.msu.edu/~pratt/freecodes/crab/home.html
8882f543	334	#ifdef __DECCXX
	335	complex cg,cphase;
	336	#else
dd82cadc	337	double_complex cg,cphase;
8882f543	338	#endif
dd82cadc	339	int mm,j;
	340	double x,y,phase,delp,cgmag;
	341	x=real(c);
	342	y=imag(c);
	343	phase=-TMath::E()*y;
	344	for(j=1;j<=100000;j++){
	345	delp=(y/(double)j)-atan(y/(double)j);
	346	phase=phase+delp;
c114f4f8	347	if(TMath::Abs(delp)<1E-10) goto CGamma_ESCAPE;
dd82cadc	348	}
dd82cadc	349	printf("oops not accurate enough, increase jmax\n");
c114f4f8	350	CGamma_ESCAPE:
3294e9ff	351	phase=phase-2.0TMath::Pi()TMath::Floor(phase/(2.0*TMath::Pi()));
c114f4f8	352	cphase=exp(fgkCI*phase);
dd82cadc	353	cgmag=sqrt(TMath::Pi()y/sinh(TMath::Pi()y));
3294e9ff	354	mm=(int)TMath::Floor(x+0.5);
dd82cadc	355	cg=cgmag*cphase;
	356	if(mm<1){
	357	for(j=1;j<=-mm+1;j++){
c114f4f8	358	cg=cg/(1.0+(double)(-j)+fgkCI*y);
dd82cadc	359	}
	360	}
	361	if(mm>1) {
	362	for(j=1;j<=mm-1;j++){
c114f4f8	363	cg=cg((double)(j)+fgkCIy);
dd82cadc	364	}
	365	}
	366	return cg;
	367	}