[u/mrichter/AliRoot.git] / PWG / Glauber / AliGlauberNucleus.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.                  *
**************************************************************************/

////////////////////////////////////////////////////////////////////////////////
//
//  AliGlauberNucleus implementation
//  support class for Glauber MC
//
//  origin: PHOBOS experiment
//  alification: Mikolaj Krzewicki, Nikhef, mikolaj.krzewicki@cern.ch
//
////////////////////////////////////////////////////////////////////////////////

#include <Riostream.h>
#include <TMath.h>
#include <TEllipse.h>
#include <TNamed.h>
#include <TObjArray.h>
#include <TF1.h>
#include <TRandom.h>
#include "AliGlauberNucleon.h"
#include "AliGlauberNucleus.h"

using std::cout;
using std::endl;
using std::cerr;
ClassImp(AliGlauberNucleus)

//______________________________________________________________________________
AliGlauberNucleus::AliGlauberNucleus(Option_t* iname, Int_t iN, Double_t iR, Double_t ia, Double_t iw, TF1* ifunc) : 
  TNamed(iname,""),
  fN(iN),
  fR(iR),
  fA(ia),
  fW(iw),
  fMinDist(-1),
  fF(0),
  fTrials(0),
  fFunction(ifunc),
  fNucleons(NULL)
{
   if (fN==0) {
      cout << "Setting up nucleus " << iname << endl;
      Lookup(iname);
   }
}

//______________________________________________________________________________
AliGlauberNucleus::~AliGlauberNucleus()
{
   if (fNucleons) {
      delete fNucleons;
   }
   delete fFunction;
}

//______________________________________________________________________________
AliGlauberNucleus::AliGlauberNucleus(const AliGlauberNucleus& in):
  TNamed(in),
  fN(in.fN),
  fR(in.fR),
  fA(in.fA),
  fW(in.fW),
  fMinDist(in.fMinDist),
  fF(in.fF),
  fTrials(in.fTrials),
  fFunction(in.fFunction),
  fNucleons(NULL)
{
  //copy ctor
  if (in.fNucleons)
    fNucleons=static_cast<TObjArray*>((in.fNucleons)->Clone());
}

//______________________________________________________________________________
AliGlauberNucleus& AliGlauberNucleus::operator=(const AliGlauberNucleus& in)
{
  //assignment
  if (&in==this) return *this;
  fN=in.fN;
  fR=in.fR;
  fA=in.fA;
  fW=in.fW;
  fMinDist=in.fMinDist;
  fF=in.fF;
  fTrials=in.fTrials;
  fFunction=in.fFunction;
  delete fNucleons;
  fNucleons=static_cast<TObjArray*>((in.fNucleons)->Clone());
  fNucleons->SetOwner();
  return *this;
}

//______________________________________________________________________________
void AliGlauberNucleus::Draw(Double_t xs, Int_t col)
{
   Double_t r = 0.5*sqrt(xs/TMath::Pi()/10.);
   TEllipse e;
   e.SetLineColor(col);
   e.SetFillColor(0);
   e.SetLineWidth(1);

   for (Int_t i = 0;i<fNucleons->GetEntries();++i) {
      AliGlauberNucleon* gn = (AliGlauberNucleon*) fNucleons->UncheckedAt(i);
      e.SetLineStyle(1);
      if (gn->IsSpectator()) e.SetLineStyle(3);
      e.DrawEllipse(gn->GetX(),gn->GetY(),r,r,0,360,0,"");
   }
}

//______________________________________________________________________________
void AliGlauberNucleus::Lookup(Option_t* name)
{
   SetName(name);

   if      (TString(name) == "p")    {fN = 1;   fR = 0.6;   fA = 0;      fW =  0;      fF = 0;}
   else if (TString(name) == "d")    {fN = 2;   fR = 0.01;  fA = 0.5882; fW =  0;      fF = 1;}
   else if (TString(name) == "dh")   {fN = 2;   fR = 0.01;  fA = 0.5882; fW =  0;      fF = 3;}
   else if (TString(name) == "dhh")  {fN = 2;   fR = 0.01;  fA = 0.5882; fW =  0;      fF = 4;}
   else if (TString(name) == "O")    {fN = 16;  fR = 2.608; fA = 0.513;  fW = -0.051;  fF = 1;}
   else if (TString(name) == "Si")   {fN = 28;  fR = 3.34;  fA = 0.580;  fW = -0.233;  fF = 1;}
   else if (TString(name) == "S")    {fN = 32;  fR = 2.54;  fA = 2.191;  fW =  0.16;   fF = 2;}
   else if (TString(name) == "Ca")   {fN = 40;  fR = 3.766; fA = 0.586;  fW = -0.161;  fF = 1;}
   else if (TString(name) == "Ni")   {fN = 58;  fR = 4.309; fA = 0.517;  fW = -0.1308; fF = 1;}
   else if (TString(name) == "Cu")   {fN = 63;  fR = 4.2;   fA = 0.596;  fW =  0;      fF = 1;}
   else if (TString(name) == "W")    {fN = 186; fR = 6.58;  fA = 0.480;  fW =  0;      fF = 1;}
   else if (TString(name) == "Au")   {fN = 197; fR = 6.38;  fA = 0.535;  fW =  0;      fF = 1;}
   else if (TString(name) == "Pb")   {fN = 208; fR = 6.62;  fA = 0.546;  fW =  0;      fF = 1;}
   else if (TString(name) == "U")    {fN = 238; fR = 6.81;  fA = 0.6;    fW =  0;      fF = 1;}
   else {
      cout << "Could not find nucleus " << name << endl;
      return;
   }

   switch (fF)
   {
      case 0: // Proton
         fFunction = new TF1("prot","x*x*exp(-x/[0])",0,10);
         fFunction->SetParameter(0,fR);
         break;
      case 1: // 3pF
         fFunction = new TF1(name,"x*x*(1+[2]*(x/[0])**2)/(1+exp((x-[0])/[1]))",0,15);
         fFunction->SetParameters(fR,fA,fW);
         break;
      case 2: // 3pG
         fFunction = new TF1("3pg","x*x*(1+[2]*(x/[0])**2)/(1+exp((x**2-[0]**2)/[1]**2))",0,15);
         fFunction->SetParameters(fR,fA,fW);
         break;
      case 3: // Hulthen
         fFunction = new TF1("f3","x*x*([0]*[1]*([0]+[1]))/(2*pi*(pow([0]-[1],2)))*pow((exp(-[0]*x)-exp(-[1]*x))/x,2)",0,10);
         fFunction->SetParameters(1/4.38,1/.85);
         break;
      case 4: // Hulthen HIJING
         fFunction = new TF1("f4","x*x*([0]*[1]*([0]+[1]))/(2*pi*(pow([0]-[1],2)))*pow((exp(-[0]*x)-exp(-[1]*x))/x,2)",0,20);
         fFunction->SetParameters(2/4.38,2/.85);
         break;
      default:
         cerr << "Could not find function type " << fF << endl;
         return;
   }
}

//______________________________________________________________________________
void AliGlauberNucleus::SetR(Double_t ir)
{
   fR = ir;
   switch (fF)
   {
      case 0: // Proton
         fFunction->SetParameter(0,fR);
         break;
      case 1: // 3pF
         fFunction->SetParameter(0,fR);
         break;
      case 2: // 3pG
         fFunction->SetParameter(0,fR);
         break;
   }
}

//______________________________________________________________________________
void AliGlauberNucleus::SetA(Double_t ia)
{
   fA = ia;
   switch (fF)
   {
      case 0: // Proton
         break;
      case 1: // 3pF
         fFunction->SetParameter(1,fA);
         break;
      case 2: // 3pG
         fFunction->SetParameter(1,fA);
         break;
   }
}

//______________________________________________________________________________
void AliGlauberNucleus::SetW(Double_t iw)
{
   fW = iw;
   switch (fF)
   {
      case 0: // Proton
         break;
      case 1: // 3pF
         fFunction->SetParameter(2,fW);
         break;
      case 2: // 3pG
         fFunction->SetParameter(2,fW);
         break;
   }
}

//______________________________________________________________________________
void AliGlauberNucleus::ThrowNucleons(Double_t xshift)
{
   if (fNucleons==0) {
      fNucleons=new TObjArray(fN);
      fNucleons->SetOwner();
      for(Int_t i=0;i<fN;i++) {
	 AliGlauberNucleon *nucleon=new AliGlauberNucleon(); 
	 fNucleons->Add(nucleon); 
      }
   } 
   
   fTrials = 0;

   Double_t sumx=0;       
   Double_t sumy=0;       
   Double_t sumz=0;       

   Bool_t hulthen = (TString(GetName())=="dh");
   if (fN==2 && hulthen) { //special treatmeant for Hulten

      Double_t r = fFunction->GetRandom()/2;
      Double_t phi = gRandom->Rndm() * 2 * TMath::Pi() ;
      Double_t ctheta = 2*gRandom->Rndm() - 1 ;
      Double_t stheta = sqrt(1-ctheta*ctheta);
     
      AliGlauberNucleon *nucleon1=(AliGlauberNucleon*)(fNucleons->UncheckedAt(0));
      AliGlauberNucleon *nucleon2=(AliGlauberNucleon*)(fNucleons->UncheckedAt(1));
      nucleon1->Reset();
      nucleon1->SetXYZ(r * stheta * cos(phi) + xshift,
		       r * stheta * sin(phi),
		       r * ctheta);
      nucleon2->Reset();
      nucleon2->SetXYZ(-nucleon1->GetX() + 2*xshift,
		       -nucleon1->GetY(),
		       -nucleon1->GetZ());
      fTrials = 1;
      return;
   }

   for (Int_t i = 0; i<fN; i++) {
      AliGlauberNucleon *nucleon=(AliGlauberNucleon*)(fNucleons->UncheckedAt(i));
      nucleon->Reset();
      while(1) {
         fTrials++;
         Double_t r = fFunction->GetRandom();
         Double_t phi = gRandom->Rndm() * 2 * TMath::Pi() ;
         Double_t ctheta = 2*gRandom->Rndm() - 1 ;
         Double_t stheta = TMath::Sqrt(1-ctheta*ctheta);
         Double_t x = r * stheta * cos(phi) + xshift;
         Double_t y = r * stheta * sin(phi);      
         Double_t z = r * ctheta;      
         nucleon->SetXYZ(x,y,z);
         if(fMinDist<0) break;
         Bool_t test=1;
         for (Int_t j = 0; j<i; j++) {
            AliGlauberNucleon *other=(AliGlauberNucleon*)fNucleons->UncheckedAt(j);
            Double_t xo=other->GetX();
            Double_t yo=other->GetY();
            Double_t zo=other->GetZ();
            Double_t dist = TMath::Sqrt((x-xo)*(x-xo)+
                                       (y-yo)*(y-yo)+
                                       (z-zo)*(z-zo));
	       
            if(dist<fMinDist) {
               test=0;
               break;
            }
         }
         if (test) break; //found nucleuon outside of mindist
      }
           
      sumx += nucleon->GetX();
      sumy += nucleon->GetY();
      sumz += nucleon->GetZ();
   }
      
   if(1) { // set the centre-of-mass to be at zero (+xshift)
      sumx = sumx/fN;  
      sumy = sumy/fN;  
      sumz = sumz/fN;  
      for (Int_t i = 0; i<fN; i++) {
         AliGlauberNucleon *nucleon=(AliGlauberNucleon*)(fNucleons->UncheckedAt(i));
         nucleon->SetXYZ(nucleon->GetX()-sumx-xshift,
                         nucleon->GetY()-sumy,
                         nucleon->GetZ()-sumz);
      }
   }
}
Commit	Line	Data
ec852657	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	//
	18	// AliGlauberNucleus implementation
	19	// support class for Glauber MC
	20	//
	21	// origin: PHOBOS experiment
	22	// alification: Mikolaj Krzewicki, Nikhef, mikolaj.krzewicki@cern.ch
	23	//
	24	////////////////////////////////////////////////////////////////////////////////
	25
19f030d3	26	#include <Riostream.h>
ec852657	27	#include <TMath.h>
	28	#include <TEllipse.h>
	29	#include <TNamed.h>
	30	#include <TObjArray.h>
	31	#include <TF1.h>
	32	#include <TRandom.h>
	33	#include "AliGlauberNucleon.h"
	34	#include "AliGlauberNucleus.h"
	35
3a7af7bd	36	using std::cout;
	37	using std::endl;
	38	using std::cerr;
ec852657	39	ClassImp(AliGlauberNucleus)
	40
	41	//______________________________________________________________________________
	42	AliGlauberNucleus::AliGlauberNucleus(Option_t* iname, Int_t iN, Double_t iR, Double_t ia, Double_t iw, TF1* ifunc) :
566fc3d0	43	TNamed(iname,""),
	44	fN(iN),
	45	fR(iR),
	46	fA(ia),
	47	fW(iw),
	48	fMinDist(-1),
	49	fF(0),
	50	fTrials(0),
	51	fFunction(ifunc),
	52	fNucleons(NULL)
ec852657	53	{
	54	if (fN==0) {
	55	cout << "Setting up nucleus " << iname << endl;
	56	Lookup(iname);
	57	}
	58	}
	59
	60	//______________________________________________________________________________
	61	AliGlauberNucleus::~AliGlauberNucleus()
	62	{
	63	if (fNucleons) {
	64	delete fNucleons;
	65	}
	66	delete fFunction;
	67	}
	68
	69	//______________________________________________________________________________
566fc3d0	70	AliGlauberNucleus::AliGlauberNucleus(const AliGlauberNucleus& in):
	71	TNamed(in),
	72	fN(in.fN),
	73	fR(in.fR),
	74	fA(in.fA),
	75	fW(in.fW),
	76	fMinDist(in.fMinDist),
	77	fF(in.fF),
	78	fTrials(in.fTrials),
	79	fFunction(in.fFunction),
	80	fNucleons(NULL)
	81	{
	82	//copy ctor
	83	if (in.fNucleons)
	84	fNucleons=static_cast<TObjArray*>((in.fNucleons)->Clone());
	85	}
	86
	87	//______________________________________________________________________________
	88	AliGlauberNucleus& AliGlauberNucleus::operator=(const AliGlauberNucleus& in)
	89	{
	90	//assignment
2047680a	91	if (&in==this) return *this;
566fc3d0	92	fN=in.fN;
	93	fR=in.fR;
	94	fA=in.fA;
	95	fW=in.fW;
	96	fMinDist=in.fMinDist;
	97	fF=in.fF;
	98	fTrials=in.fTrials;
	99	fFunction=in.fFunction;
	100	delete fNucleons;
	101	fNucleons=static_cast<TObjArray*>((in.fNucleons)->Clone());
	102	fNucleons->SetOwner();
	103	return *this;
	104	}
	105
	106	//______________________________________________________________________________
ec852657	107	void AliGlauberNucleus::Draw(Double_t xs, Int_t col)
	108	{
	109	Double_t r = 0.5*sqrt(xs/TMath::Pi()/10.);
	110	TEllipse e;
	111	e.SetLineColor(col);
	112	e.SetFillColor(0);
	113	e.SetLineWidth(1);
	114
	115	for (Int_t i = 0;i<fNucleons->GetEntries();++i) {
14244e14	116	AliGlauberNucleon* gn = (AliGlauberNucleon*) fNucleons->UncheckedAt(i);
ec852657	117	e.SetLineStyle(1);
	118	if (gn->IsSpectator()) e.SetLineStyle(3);
	119	e.DrawEllipse(gn->GetX(),gn->GetY(),r,r,0,360,0,"");
	120	}
	121	}
	122
	123	//______________________________________________________________________________
	124	void AliGlauberNucleus::Lookup(Option_t* name)
	125	{
	126	SetName(name);
	127
	128	if (TString(name) == "p") {fN = 1; fR = 0.6; fA = 0; fW = 0; fF = 0;}
	129	else if (TString(name) == "d") {fN = 2; fR = 0.01; fA = 0.5882; fW = 0; fF = 1;}
	130	else if (TString(name) == "dh") {fN = 2; fR = 0.01; fA = 0.5882; fW = 0; fF = 3;}
	131	else if (TString(name) == "dhh") {fN = 2; fR = 0.01; fA = 0.5882; fW = 0; fF = 4;}
	132	else if (TString(name) == "O") {fN = 16; fR = 2.608; fA = 0.513; fW = -0.051; fF = 1;}
	133	else if (TString(name) == "Si") {fN = 28; fR = 3.34; fA = 0.580; fW = -0.233; fF = 1;}
	134	else if (TString(name) == "S") {fN = 32; fR = 2.54; fA = 2.191; fW = 0.16; fF = 2;}
	135	else if (TString(name) == "Ca") {fN = 40; fR = 3.766; fA = 0.586; fW = -0.161; fF = 1;}
	136	else if (TString(name) == "Ni") {fN = 58; fR = 4.309; fA = 0.517; fW = -0.1308; fF = 1;}
	137	else if (TString(name) == "Cu") {fN = 63; fR = 4.2; fA = 0.596; fW = 0; fF = 1;}
	138	else if (TString(name) == "W") {fN = 186; fR = 6.58; fA = 0.480; fW = 0; fF = 1;}
	139	else if (TString(name) == "Au") {fN = 197; fR = 6.38; fA = 0.535; fW = 0; fF = 1;}
	140	else if (TString(name) == "Pb") {fN = 208; fR = 6.62; fA = 0.546; fW = 0; fF = 1;}
	141	else if (TString(name) == "U") {fN = 238; fR = 6.81; fA = 0.6; fW = 0; fF = 1;}
	142	else {
	143	cout << "Could not find nucleus " << name << endl;
	144	return;
	145	}
	146
	147	switch (fF)
	148	{
	149	case 0: // Proton
	150	fFunction = new TF1("prot","xxexp(-x/[0])",0,10);
	151	fFunction->SetParameter(0,fR);
	152	break;
	153	case 1: // 3pF
	154	fFunction = new TF1(name,"xx(1+[2](x/[0])*2)/(1+exp((x-[0])/[1]))",0,15);
	155	fFunction->SetParameters(fR,fA,fW);
	156	break;
	157	case 2: // 3pG
	158	fFunction = new TF1("3pg","xx(1+[2](x/[0])2)/(1+exp((x2-[0]2)/[1]*2))",0,15);
	159	fFunction->SetParameters(fR,fA,fW);
	160	break;
	161	case 3: // Hulthen
	162	fFunction = new TF1("f3","xx([0][1]([0]+[1]))/(2pi(pow([0]-[1],2)))pow((exp(-[0]x)-exp(-[1]*x))/x,2)",0,10);
	163	fFunction->SetParameters(1/4.38,1/.85);
	164	break;
	165	case 4: // Hulthen HIJING
	166	fFunction = new TF1("f4","xx([0][1]([0]+[1]))/(2pi(pow([0]-[1],2)))pow((exp(-[0]x)-exp(-[1]*x))/x,2)",0,20);
	167	fFunction->SetParameters(2/4.38,2/.85);
	168	break;
	169	default:
	170	cerr << "Could not find function type " << fF << endl;
	171	return;
	172	}
	173	}
	174
	175	//______________________________________________________________________________
	176	void AliGlauberNucleus::SetR(Double_t ir)
	177	{
	178	fR = ir;
	179	switch (fF)
	180	{
181	case 0: // Proton
182	fFunction->SetParameter(0,fR);
183	break;
184	case 1: // 3pF
185	fFunction->SetParameter(0,fR);
186	break;
187	case 2: // 3pG
188	fFunction->SetParameter(0,fR);
189	break;
190	}
191	}
192
193	//______________________________________________________________________________
194	void AliGlauberNucleus::SetA(Double_t ia)
195	{
196	fA = ia;
197	switch (fF)
198	{
199	case 0: // Proton
200	break;
201	case 1: // 3pF
202	fFunction->SetParameter(1,fA);
203	break;
204	case 2: // 3pG
205	fFunction->SetParameter(1,fA);
206	break;
207	}
208	}
209
210	//______________________________________________________________________________
211	void AliGlauberNucleus::SetW(Double_t iw)
212	{
213	fW = iw;
214	switch (fF)
215	{
216	case 0: // Proton
217	break;
218	case 1: // 3pF
219	fFunction->SetParameter(2,fW);
220	break;
221	case 2: // 3pG
222	fFunction->SetParameter(2,fW);
223	break;
224	}
225	}
226
227	//______________________________________________________________________________
228	void AliGlauberNucleus::ThrowNucleons(Double_t xshift)
229	{
230	if (fNucleons==0) {
231	fNucleons=new TObjArray(fN);
232	fNucleons->SetOwner();
233	for(Int_t i=0;i<fN;i++) {
234	AliGlauberNucleon *nucleon=new AliGlauberNucleon();
235	fNucleons->Add(nucleon);
236	}
237	}
238
239	fTrials = 0;
240
241	Double_t sumx=0;
242	Double_t sumy=0;
243	Double_t sumz=0;
244
245	Bool_t hulthen = (TString(GetName())=="dh");
246	if (fN==2 && hulthen) { //special treatmeant for Hulten
247
248	Double_t r = fFunction->GetRandom()/2;
249	Double_t phi = gRandom->Rndm() * 2 * TMath::Pi() ;
250	Double_t ctheta = 2*gRandom->Rndm() - 1 ;
251	Double_t stheta = sqrt(1-ctheta*ctheta);
252
14244e14	253	AliGlauberNucleon nucleon1=(AliGlauberNucleon)(fNucleons->UncheckedAt(0));
14244e14	254	AliGlauberNucleon nucleon2=(AliGlauberNucleon)(fNucleons->UncheckedAt(1));
ec852657	255	nucleon1->Reset();
	256	nucleon1->SetXYZ(r * stheta * cos(phi) + xshift,
	257	r * stheta * sin(phi),
	258	r * ctheta);
	259	nucleon2->Reset();
	260	nucleon2->SetXYZ(-nucleon1->GetX() + 2*xshift,
	261	-nucleon1->GetY(),
	262	-nucleon1->GetZ());
	263	fTrials = 1;
	264	return;
	265	}
	266
	267	for (Int_t i = 0; i<fN; i++) {
14244e14	268	AliGlauberNucleon nucleon=(AliGlauberNucleon)(fNucleons->UncheckedAt(i));
ec852657	269	nucleon->Reset();
	270	while(1) {
	271	fTrials++;
	272	Double_t r = fFunction->GetRandom();
	273	Double_t phi = gRandom->Rndm() * 2 * TMath::Pi() ;
	274	Double_t ctheta = 2*gRandom->Rndm() - 1 ;
	275	Double_t stheta = TMath::Sqrt(1-ctheta*ctheta);
	276	Double_t x = r * stheta * cos(phi) + xshift;
	277	Double_t y = r * stheta * sin(phi);
	278	Double_t z = r * ctheta;
	279	nucleon->SetXYZ(x,y,z);
	280	if(fMinDist<0) break;
	281	Bool_t test=1;
	282	for (Int_t j = 0; j<i; j++) {
14244e14	283	AliGlauberNucleon other=(AliGlauberNucleon)fNucleons->UncheckedAt(j);
ec852657	284	Double_t xo=other->GetX();
	285	Double_t yo=other->GetY();
	286	Double_t zo=other->GetZ();
	287	Double_t dist = TMath::Sqrt((x-xo)*(x-xo)+
	288	(y-yo)*(y-yo)+
	289	(z-zo)*(z-zo));
	290
	291	if(dist<fMinDist) {
	292	test=0;
	293	break;
	294	}
	295	}
	296	if (test) break; //found nucleuon outside of mindist
	297	}
	298
	299	sumx += nucleon->GetX();
	300	sumy += nucleon->GetY();
	301	sumz += nucleon->GetZ();
	302	}
	303
	304	if(1) { // set the centre-of-mass to be at zero (+xshift)
	305	sumx = sumx/fN;
	306	sumy = sumy/fN;
	307	sumz = sumz/fN;
	308	for (Int_t i = 0; i<fN; i++) {
14244e14	309	AliGlauberNucleon nucleon=(AliGlauberNucleon)(fNucleons->UncheckedAt(i));
ec852657	310	nucleon->SetXYZ(nucleon->GetX()-sumx-xshift,
	311	nucleon->GetY()-sumy,
	312	nucleon->GetZ()-sumz);
	313	}
	314	}
	315	}
	316