Fix for the problem during PbPb run of Nov 2010 (Indra)
[u/mrichter/AliRoot.git] / JETAN / AliDAJetFinder.cxx
1
2 //  **************************************************************************
3 //  * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 //  *                                                                        *
5 //  * Author: The ALICE Off-line Project.                                    *
6 //  * Contributors are mentioned in the code where appropriate.              *
7 //  *                                                                        *
8 //  * Permission to use, copy, modify and distribute this software and its   *
9 //  * documentation strictly for non-commercial purposes is hereby granted   *
10 //  * without fee, provided that the above copyright notice appears in all   *
11 //  * copies and that both the copyright notice and this permission notice   *
12 //  * appear in the supporting documentation. The authors make no claims     *
13 //  * about the suitability of this software for any purpose. It is          *
14 //  * provided "as is" without express or implied warranty.                  *
15 //  **************************************************************************
16
17 //-----------------------------------------------------------------------------------
18 // Jet finder based on Deterministic Annealing
19 // For further informations about the DA working features see:
20 // Phys.Lett. B601 (2004) 56-63 (http://arxiv.org/abs/hep-ph/0407214)
21 // Author: Davide Perrino (davide.perrino@ba.infn.it, davide.perrino@cern.ch)
22 //-----------------------------------------------------------------------------------
23
24 #include <TMath.h>
25 #include <TRandom2.h>
26 #include <TClonesArray.h>
27 #include "AliJetReaderHeader.h"
28 #include "AliJetReader.h"
29 #include "AliDAJetHeader.h"
30 #include "AliDAJetFinder.h"
31
32 ClassImp(AliDAJetFinder)
33
34
35 //-----------------------------------------------------------------------------------
36 AliDAJetFinder::AliDAJetFinder():
37         AliJetFinder(),
38         fAlpha(1.01),
39         fDelta(1e-8),
40         fAvDist(1e-6),
41         fEps(1e-4),
42         fEpsMax(1e-2),
43         fNloopMax(100),
44         fBeta(0.1),
45         fNclustMax(0),
46         fNin(0),
47         fNeff(0)
48 {
49         // Constructor
50 }
51
52 //-----------------------------------------------------------------------------------
53 AliDAJetFinder::~AliDAJetFinder()
54 {
55         // Destructor
56 }
57
58 //-----------------------------------------------------------------------------------
59 void AliDAJetFinder::FindJets()  
60 {
61 // Find the jets in current event
62 // 
63         Float_t betaStop=100.;
64         fDebug = fHeader->GetDebug();
65
66         Double_t dEtSum=0;
67         Double_t *xData[2];
68         TVectorD *vPx = new TVectorD();
69         TVectorD *vPy = new TVectorD();
70         TMatrixD *mPyx= new TMatrixD();
71         TMatrixD *mY  = new TMatrixD();
72         InitDetAnn(dEtSum,xData,vPx,vPy,mPyx,mY);
73         if (fNin < fNclustMax){
74           delete [] xData[0], delete [] xData[1];
75           delete vPx;
76           delete vPy;
77           delete mPyx;
78           delete mY;
79           return;
80         }
81         Int_t nc=1, nk;
82         DoubleClusters(nc,nk,vPy,mY);
83         do{                                     //loop over beta
84                 fBeta*=fAlpha;
85                 Annealing(nk,xData,vPx,vPy,mPyx,mY);
86                 NumCl(nc,nk,vPy,mPyx,mY);
87         }while((fBeta<betaStop || nc<4) && nc<fNclustMax);
88
89         Int_t *xx=new Int_t[fNeff];
90         EndDetAnn(nk,xData,xx,dEtSum,vPx,vPy,mPyx,mY);
91         StoreJets(nk,xData,xx,mY);
92         delete [] xx;
93
94         delete [] xData[0], delete [] xData[1];
95         delete mPyx;
96         delete mY;
97         delete vPx;
98         delete vPy;
99
100 }
101
102 //-----------------------------------------------------------------------------------
103 void AliDAJetFinder::InitDetAnn(Double_t &dEtSum,Double_t **xData,TVectorD *vPx,TVectorD *vPy,TMatrixD *mPyx,TMatrixD *mY)
104 {
105 //Initialise the variables used by the algorithm
106         fBeta=0.1;
107         fNclustMax = ((AliDAJetHeader*)fHeader)->GetFixedCl() ? 
108             ((AliDAJetHeader*)fHeader)->GetNclustMax() : 
109             TMath::Max((Int_t)TMath::Sqrt(fNin),5);
110         Float_t etaEff = ((AliDAJetHeader*)fHeader)->GetEtaEff();
111         TClonesArray *lvArray = fReader->GetMomentumArray();
112         Int_t nEntr = lvArray->GetEntries();
113         fNin=0;
114         for (Int_t iEn=0; iEn<nEntr; iEn++) if (fReader->GetCutFlag(iEn)==1) fNin++;
115
116         fNeff = ((AliDAJetHeader*)fHeader)->GetNeff();
117         fNeff = TMath::Max(fNeff,fNin);
118         Double_t *xEta = new Double_t[fNeff];
119         Double_t *xPhi = new Double_t[fNeff];
120         xData[0]=xEta; xData[1]=xPhi;
121         vPx->ResizeTo(fNeff);
122         Int_t iIn=0;
123         for (Int_t iEn=0; iEn<nEntr; iEn++){
124                 if (fReader->GetCutFlag(iEn)==0) continue;
125                 TLorentzVector *lv=(TLorentzVector*)lvArray->At(iEn);
126                 xEta[iIn] = lv->Eta();
127                 xPhi[iIn] = lv->Phi()<0 ? lv->Phi() + 2*TMath::Pi() : lv->Phi();
128                 (*vPx)(iIn)=lv->Pt();
129                 dEtSum+=(*vPx)(iIn);
130                 iIn++;
131         }
132         TRandom2 r;
133         r.SetSeed(0);
134         for (iIn=fNin; iIn<fNeff; iIn++){
135                 xEta[iIn]=r.Uniform(-1*etaEff,etaEff);
136                 xPhi[iIn]=r.Uniform(0.,2*TMath::Pi());
137                 (*vPx)(iIn)=r.Uniform(0.01,0.02);
138                 dEtSum+=(*vPx)(iIn);
139         }
140         for (iIn=0; iIn<fNeff; iIn++) (*vPx)(iIn)=(*vPx)(iIn)/dEtSum;
141
142         Int_t njdim=2*fNclustMax+1;
143         mPyx->ResizeTo(fNeff,njdim);
144         mY->ResizeTo(4,njdim);
145         vPy->ResizeTo(njdim);
146         mY->Zero();mPyx->Zero();vPy->Zero();
147         (*vPy)(0)=1;
148         TMatrixDColumn(*mPyx,0)=1;
149         Double_t ypos=0,xpos=0;
150         for (iIn=0; iIn<fNeff; iIn++){
151                 (*mY)(0,0)+=(*vPx)(iIn)*xEta[iIn];
152                 ypos+=(*vPx)(iIn)*TMath::Sin(xPhi[iIn]);
153                 xpos+=(*vPx)(iIn)*TMath::Cos(xPhi[iIn]);
154         }
155         (*mY)(1,0)=(atan2(ypos,xpos)>0) ? atan2(ypos,xpos) : atan2(ypos,xpos)+2*TMath::Pi();
156 }
157
158 //-----------------------------------------------------------------------------------
159 void AliDAJetFinder::DoubleClusters(Int_t nc,Int_t &nk,  TVectorD *vPy, TMatrixD *mY) const
160 {
161 // Return double clusters
162         for(Int_t iClust=0; iClust<nc; iClust++){
163                 (*vPy)(iClust)=(*vPy)(iClust)/2;
164                 (*vPy)(nc+iClust)=(*vPy)(iClust);
165                 for(Int_t iComp=0; iComp<3; iComp++) (*mY)(iComp,nc+iClust)=(*mY)(iComp,iClust);
166         }
167         nk=2*nc;
168 }
169
170 //-----------------------------------------------------------------------------------
171 void AliDAJetFinder::Annealing(Int_t nk,Double_t **xData,  TVectorD *vPx,  TVectorD *vPy,  TMatrixD *mPyx,  TMatrixD *mY)
172 {
173 // Main part of the algorithm
174         const Double_t pi=TMath::Pi();
175         TVectorD *py = new TVectorD(nk);
176         TVectorD *p  = new TVectorD(nk);
177         TMatrixD *y  = new TMatrixD(4,nk);
178         TMatrixD *y1 = new TMatrixD(4,nk);
179         TMatrixD *ry = new TMatrixD(2,nk);
180         Double_t *xEta = xData[0];
181         Double_t *xPhi = xData[1];
182         Double_t Dist(TVectorD,TVectorD);
183
184         Double_t df[2]={fReader->GetReaderHeader()->GetFiducialEtaMax(),pi};
185         TVectorD vPart(2);
186         Double_t *m = new Double_t[nk];
187         Double_t chi,chi1;
188         do{
189                 Int_t nloop=0;
190                 for (Int_t iClust=0; iClust<nk; iClust++){
191                         for (Int_t i=0; i<3; i++)(*y1)(i,iClust)=(*mY)(i,iClust);
192                         (*py)(iClust)=(*vPy)(iClust);
193                 }
194         //perturbation of codevectors
195                 Double_t seed=1000000*gRandom->Rndm(24);
196                 ry->Randomize(-0.5,0.5,seed);
197                 for (Int_t i=0; i<2; i++){
198                         for (Int_t iClust=0; iClust<nk/2; iClust++)
199                                 (*y1)(i,iClust)+=((*ry)(i,iClust)+TMath::Sign(0.5,(*ry)(i,iClust)))*fDelta*df[i];
200                         for (Int_t iClust=nk/2; iClust<nk; iClust++)
201                                 (*y1)(i,iClust)-=((*ry)(i,iClust-nk/2)+TMath::Sign(0.5,(*ry)(i,iClust-nk/2)))*fDelta*df[i];
202                 }
203                 do{
204         //recalculate conditional probabilities
205                         nloop++;
206                         for (Int_t iIn=0; iIn<fNeff; iIn++){
207                                 vPart(0)=xEta[iIn]; vPart(1)=xPhi[iIn];
208                                 for(Int_t iClust=0; iClust<nk; iClust++){
209                                         (*mPyx)(iIn,iClust)=-log((*py)(iClust))+fBeta*Dist(vPart,TMatrixDColumn(*y1,iClust));
210                                         m[iClust]=(*mPyx)(iIn,iClust);
211                                 }
212                                 Double_t pyxNorm=0;
213                                 Double_t minPyx=TMath::MinElement(nk,m);
214                                 for (Int_t iClust=0; iClust<nk; iClust++){
215                                         (*mPyx)(iIn,iClust)-=minPyx;
216                                         (*mPyx)(iIn,iClust)=exp(-(*mPyx)(iIn,iClust));
217                                         pyxNorm+=(*mPyx)(iIn,iClust);
218                                 }
219                                 for (Int_t iClust=0; iClust<nk; iClust++) (*mPyx)(iIn,iClust)/=pyxNorm;
220                         }
221                         p->Zero();
222                         y->Zero();
223         //recalculate codevectors
224                         for (Int_t iClust=0; iClust<nk; iClust++){
225                                 Double_t xpos=0,ypos=0,pxy;
226                                 for (Int_t iIn=0; iIn<fNeff; iIn++) (*p)(iClust)+=(*vPx)(iIn)*(*mPyx)(iIn,iClust);
227                                 for (Int_t iIn=0; iIn<fNeff; iIn++){
228                                         pxy=(*vPx)(iIn)*(*mPyx)(iIn,iClust)/(*p)(iClust);
229                                         ypos+=pxy*TMath::Sin(xPhi[iIn]);
230                                         xpos+=pxy*TMath::Cos(xPhi[iIn]);
231                                         (*y)(0,iClust)+=pxy*xEta[iIn];
232                                 }
233                                 (*y)(1,iClust)=(atan2(ypos,xpos)>0) ? atan2(ypos,xpos) : atan2(ypos,xpos)+2*pi;
234                         }
235         //verify codevectors' stability
236                         chi=0;
237                         for (Int_t iClust=0; iClust<nk; iClust++){
238                                 chi1=TMath::CosH((*y1)(0,iClust)-(*y)(0,iClust))-TMath::Cos((*y1)(1,iClust)-(*y)(1,iClust));
239                                 chi1/=(2*TMath::CosH((*y1)(0,iClust))*TMath::CosH((*y)(0,iClust)));
240                                 chi1*=chi1;
241                                 if (chi1>chi) chi=chi1;
242                         }
243                         chi=TMath::Sqrt(chi);
244                         for (Int_t iClust=0; iClust<nk; iClust++){
245                                 for (Int_t i=0; i<2; i++) (*y1)(i,iClust)=(*y)(i,iClust);
246                                 (*py)(iClust)=(*p)(iClust);
247                         }
248                         if (nloop>fNloopMax){
249                                 if (chi<fEpsMax || nloop>500) break;
250                         }
251                 }while (chi>fEps);
252         }while (chi>fEpsMax);
253         for (Int_t iClust=0; iClust<nk; iClust++){                              //set codevectors and probability equal to those calculated
254                 for (Int_t i=0; i<2; i++) (*mY)(i,iClust)=(*y)(i,iClust);
255                 (*vPy)(iClust)=(*p)(iClust);
256         }
257     delete py;
258     delete p;
259     delete y;
260     delete y1;
261     delete ry;
262     delete [] m;
263 }
264
265 //-----------------------------------------------------------------------------------
266 void AliDAJetFinder::NumCl(Int_t &nc,Int_t &nk,TVectorD *vPy,  TMatrixD *mPyx,TMatrixD *mY)
267 {
268     // Number of clusters
269         static Bool_t growcl=true;
270         
271         if (nk==2) growcl=true;
272         if (growcl){
273 //verify if two codevectors are equal within fAvDist
274                 Int_t *nSame = new Int_t[nk];
275                 Int_t **iSame = new Int_t*[nk];
276                 Int_t **cont = new Int_t*[nk];
277                 for (Int_t iClust=0; iClust<nk; iClust++) cont[iClust]=new Int_t[nk],iSame[iClust]=new Int_t[nk];
278                 for (Int_t iClust=0; iClust<nk; iClust++){
279                         iSame[iClust][iClust]=1;
280                         for (Int_t iClust1=iClust+1; iClust1<nk; iClust1++){
281                                 Double_t eta  = (*mY)(0,iClust) ; Double_t phi  = (*mY)(1,iClust);
282                                 Double_t eta1 = (*mY)(0,iClust1); Double_t phi1 = (*mY)(1,iClust1);
283                                 Double_t distCl=(TMath::CosH(eta-eta1)-TMath::Cos(phi-phi1))/(2*TMath::CosH(eta)*TMath::CosH(eta1));
284                                 if (distCl < fAvDist) iSame[iClust][iClust1]=iSame[iClust1][iClust]=1;
285                                 else iSame[iClust][iClust1]=iSame[iClust1][iClust]=0;
286                         }
287                 }
288                 ReduceClusters(iSame,nk,nc,cont,nSame);
289                 if (nc >= fNclustMax) growcl=false;
290 //recalculate the nc distinct codevectors
291                 TMatrixD *pyx = new TMatrixD(fNeff,2*nc);
292                 TVectorD *py = new TVectorD(nk);
293                 TMatrixD *y1  = new TMatrixD(3,nk);
294                 for (Int_t iClust=0; iClust<nc; iClust++){
295                         for(Int_t j=0; j<nSame[iClust]; j++){
296                                 Int_t iClust1 = cont[iClust][j];
297                                 for (Int_t iIn=0; iIn<fNeff; iIn++) (*pyx)(iIn,iClust)+=(*mPyx)(iIn,iClust1);
298                                 (*py)(iClust)+=(*vPy)(iClust1);
299                                 for (Int_t i=0; i<2; i++) (*y1)(i,iClust)+=(*mY)(i,iClust1);
300                         }
301                         for (Int_t i=0; i<2; i++) (*y1)(i,iClust)/=nSame[iClust];
302                 }
303                 for (Int_t iClust=0; iClust<nk; iClust++) delete [] cont[iClust], delete [] iSame[iClust];
304                 delete [] iSame;
305                 delete [] cont;
306                 delete [] nSame;
307                 if (nc > nk/2){
308                         for (Int_t iClust=0; iClust<nc; iClust++){
309                                 for (Int_t iIn=0; iIn<fNeff; iIn++) (*mPyx)(iIn,iClust)=(*pyx)(iIn,iClust);
310                                 for (Int_t iComp=0; iComp<2; iComp++) (*mY)(iComp,iClust)=(*y1)(iComp,iClust);
311                                 (*vPy)(iClust)=(*py)(iClust);
312                         }
313                         nk=nc;
314                         if (growcl) DoubleClusters(nc,nk,vPy,mY);
315                 }
316                 delete pyx;
317                 delete py;
318                 delete y1;
319         }
320
321 }
322
323 //-----------------------------------------------------------------------------------
324 void AliDAJetFinder::ReduceClusters(Int_t **iSame,Int_t nc,Int_t &ncout,Int_t **cont,Int_t *nSameOut) const
325 {
326 // Reduction step
327         Int_t *nSame = new Int_t[nc];
328         Int_t *iperm = new Int_t[nc];
329         Int_t *go = new Int_t[nc];
330         for (Int_t iCl=0; iCl<nc; iCl++){
331                 nSame[iCl]=0;
332                 for (Int_t jCl=0; jCl<nc; jCl++) nSame[iCl]+=iSame[iCl][jCl], cont[iCl][jCl]=0;
333                 iperm[iCl]=iCl;
334                 go[iCl]=1;
335         }
336         TMath::Sort(nc,nSame,iperm,true);
337         Int_t l=0;
338         for (Int_t iCl=0; iCl<nc; iCl++){
339                 Int_t k=iperm[iCl];
340                 if (go[k] == 1){
341                         Int_t m=0;
342                         for (Int_t jCl=0; jCl<nc; jCl++){
343                                 if (iSame[k][jCl] == 1){
344                                         cont[l][m]=jCl;
345                                         go[jCl]=0;
346                                         m++;
347                                 }
348                         }
349                         nSameOut[l]=m;
350                         l++;
351                 }
352         }
353         ncout=l;
354         delete [] nSame;
355         delete [] iperm;
356         delete [] go;
357 }
358
359 //-----------------------------------------------------------------------------------
360 void AliDAJetFinder::EndDetAnn(Int_t &nk,Double_t **xData,Int_t *xx,Double_t etx,TVectorD *vPx,TVectorD *vPy,TMatrixD *mPyx,TMatrixD *mY)
361 {
362 //now assign each particle to only one cluster
363         Double_t *clusters=new Double_t[nk];
364         for (Int_t iIn=0; iIn<fNeff; iIn++){
365                 for (Int_t iClust=0; iClust<nk; iClust++) clusters[iClust]=(*mPyx)(iIn,iClust);
366                 xx[iIn]=TMath::LocMax(nk,clusters);
367         }
368         delete [] clusters;
369         
370 //recalculate codevectors, having all p(y|x)=0 or 1
371         Double_t *xEta = xData[0];
372         Double_t *xPhi = xData[1];
373         mY->Zero();
374         mPyx->Zero();
375         vPy->Zero();
376         for (Int_t iIn=0; iIn<fNin; iIn++){
377                 Int_t iClust=xx[iIn];
378                 (*mPyx)(iIn,iClust)=1;
379                 (*vPy)(iClust)+=(*vPx)(iIn);
380                 (*mY)(0,iClust)+=(*vPx)(iIn)*xEta[iIn];
381                 (*mY)(3,iClust)+=(*vPx)(iIn)*etx;
382         }
383         Int_t k=0;
384         for (Int_t iClust=0; iClust<nk; iClust++){
385                 if ((*vPy)(iClust)>0){
386                         Double_t xpos=0,ypos=0,pxy;
387                         for (Int_t iIn=0; iIn<fNin; iIn++){
388                                 pxy=(*vPx)(iIn)*(*mPyx)(iIn,iClust)/(*vPy)(iClust);
389                                 ypos+=pxy*TMath::Sin(xPhi[iIn]);
390                                 xpos+=pxy*TMath::Cos(xPhi[iIn]);
391                                 if (xx[iIn]==iClust) xx[iIn]=k;
392                         }
393                         (*mY)(0,k)=(*mY)(0,iClust)/(*vPy)(iClust);
394                         (*mY)(1,k)=(atan2(ypos,xpos)>0) ? atan2(ypos,xpos) : atan2(ypos,xpos)+2*TMath::Pi();
395                         (*mY)(3,k)=(*mY)(3,iClust);
396                         k++;
397                 }
398         }
399         nk=k;
400 }
401
402 //-----------------------------------------------------------------------------------
403 void AliDAJetFinder::StoreJets(Int_t nk, Double_t **xData, Int_t *xx, TMatrixD *mY)
404 {
405 //evaluate significant clusters properties
406         const Double_t pi=TMath::Pi();
407         AliJetReaderHeader *rHeader=fReader->GetReaderHeader();
408         Float_t dFidEtaMax = rHeader->GetFiducialEtaMax();
409         Float_t dFidEtaMin = rHeader->GetFiducialEtaMin();
410         Float_t dFiducialEta= dFidEtaMax - dFidEtaMin;
411         Double_t *xEta = xData[0];
412         Double_t *xPhi = xData[1];
413         Int_t nEff = 0;
414         for (Int_t i=0; i<fNeff; i++) if (xEta[i]<dFidEtaMax && xEta[i]>dFidEtaMin) nEff++;
415         Double_t dMeanDist=TMath::Sqrt(2*dFiducialEta*pi/nEff);
416         Bool_t   *isJet = new Bool_t[nk];
417         Double_t *etNoBg= new Double_t[nk];
418         Double_t *dDeltaEta=new Double_t[nk];
419         Double_t *dDeltaPhi=new Double_t[nk];
420         Double_t *surf  = new Double_t[nk];
421         Double_t *etDens= new Double_t[nk];
422         for (Int_t iClust=0; iClust<nk; iClust++){
423                 isJet[iClust]=false;
424                 Double_t dEtaMin=10.,dEtaMax=-10.,dPhiMin=10.,dPhiMax=0.;
425                 for (Int_t iIn=0; iIn<fNeff; iIn++){
426                         if (xx[iIn]!=iClust || xEta[iIn]>dFidEtaMax || xEta[iIn]<dFidEtaMin) continue;
427                         if (xEta[iIn] < dEtaMin) dEtaMin=xEta[iIn];
428                         if (xEta[iIn] > dEtaMax) dEtaMax=xEta[iIn];
429                         Double_t dPhi=xPhi[iIn]-(*mY)(1,iClust);
430                         if      (dPhi > pi     ) dPhi-=2*pi;
431                         else if (dPhi < (-1)*pi) dPhi+=2*pi;
432                         if      (dPhi < dPhiMin) dPhiMin=dPhi;
433                         else if (dPhi > dPhiMax) dPhiMax=dPhi;
434                 }
435                 dDeltaEta[iClust]=dEtaMax-dEtaMin+dMeanDist;
436                 dDeltaPhi[iClust]=dPhiMax-dPhiMin+dMeanDist;
437                 surf[iClust]=0.25*pi*dDeltaEta[iClust]*dDeltaPhi[iClust];
438                 etDens[iClust]=(*mY)(3,iClust)/surf[iClust];
439         }
440
441         if (((AliDAJetHeader*)fHeader)->GetSelJets()){
442                 for (Int_t iClust=0; iClust<nk; iClust++){
443                         if (!isJet[iClust] && (*mY)(0,iClust)<dFidEtaMax && (*mY)(0,iClust)>dFidEtaMin){
444                                 Double_t etDensMed=0.;
445                                 Double_t etDensSqr=0.;
446                                 Int_t norm=0;
447                                 for (Int_t iClust1=0; iClust1<nk; iClust1++){
448                                         if(iClust1!=iClust && (*mY)(0,iClust)<dFidEtaMax && (*mY)(0,iClust)>dFidEtaMin){
449                                                 etDensMed+=etDens[iClust1];
450                                                 etDensSqr+=TMath::Power(etDens[iClust1],2);
451                                                 norm++;
452                                         }
453                                 }
454                                 etDensMed/=TMath::Max(norm,1);
455                                 etDensSqr/=TMath::Max(norm,1);
456                                 Double_t deltaEtDens=TMath::Sqrt(etDensSqr-TMath::Power(etDensMed,2));
457                                 if ((*mY)(3,iClust) > (etDensMed+deltaEtDens)*surf[iClust]) isJet[iClust]=kTRUE;
458                                 etNoBg[iClust]=(*mY)(3,iClust)-etDensMed*surf[iClust];
459                         }
460                 }
461                 for (Int_t iClust=0; iClust<nk; iClust++){
462                         if (isJet[iClust]){
463                                 Double_t etDensMed=0;
464                                 Double_t extSurf=2*dFiducialEta*pi;
465                                 for (Int_t iClust1=0; iClust1<nk; iClust1++){
466                                         if (!isJet[iClust1]) etDensMed+=(*mY)(3,iClust1);
467                                         else extSurf-=surf[iClust1];
468                                 }
469                                 etDensMed/=extSurf;
470                                 etNoBg[iClust]=(*mY)(3,iClust)-etDensMed*surf[iClust];
471                                 if (etNoBg[iClust]<((AliDAJetHeader*)fHeader)->GetEtMin()){
472                                         isJet[iClust]=kFALSE;
473                                         iClust=-1;
474                                 }
475                         }
476                 }
477         } else {
478                 for (Int_t iClust=0; iClust<nk; iClust++){
479                         isJet[iClust]=true;
480                         etNoBg[iClust]=(*mY)(3,iClust);
481                 }
482         }
483         delete [] etDens;
484         delete [] surf;
485         
486 //now add selected jets to the list
487         Int_t *iSort = new Int_t[nk];
488         TMath::Sort(nk,etNoBg,iSort,true);
489         Int_t iCl = 0;
490         TRefArray *refs = 0;
491         Bool_t fromAod = !strcmp(fReader->ClassName(),"AliJetAODReader");
492         if (fromAod) refs = fReader->GetReferences();
493         for (Int_t iClust=0; iClust<nk; iClust++){                                                                      //clusters loop
494                 iCl=iSort[iClust];
495                 if (isJet[iCl]){                                                                                                                //choose cluster
496                         Float_t px,py,pz,en;
497                         px = (*mY)(3,iCl)*TMath::Cos((*mY)(1,iCl));
498                         py = (*mY)(3,iCl)*TMath::Sin((*mY)(1,iCl));
499                         pz = (*mY)(3,iCl)/TMath::Tan(2.0 * TMath::ATan(TMath::Exp(-(*mY)(0,iCl))));
500                         en = TMath::Sqrt(px * px + py * py + pz * pz);
501                         AliAODJet jet(px, py, pz, en);
502                         if (fromAod){
503                                 Int_t iIn=0;
504                                 Int_t nEntr = fReader->GetMomentumArray()->GetEntries();
505                                 for (Int_t iEn=0; iEn<nEntr; iEn++){
506                                         if (fReader->GetCutFlag(iEn)==0) continue;
507                                         if (xx[iIn]==iCl) jet.AddTrack(refs->At(iEn));
508                                         iIn++;
509                                 }
510                         }
511                         AddJet(jet);
512                         if (fDebug > 0) printf("jet %d, Eta: %f, Phi: %f, Et: %f\n",iCl,jet.Eta(),jet.Phi(),jet.Pt());
513                 }
514         }
515         delete [] dDeltaEta; delete [] dDeltaPhi;
516         delete [] etNoBg;
517         delete [] isJet;
518         delete [] iSort;
519 }
520
521 //-----------------------------------------------------------------------------------
522 Double_t Dist(TVectorD x,TVectorD y)
523 {
524 // Squared distance
525         const Double_t pi=TMath::Pi();
526         Double_t dphi=TMath::Abs(x(1)-y(1));
527         if (dphi > pi) dphi=2*pi-dphi;
528         Double_t dist=pow(x(0)-y(0),2)+pow(dphi,2);
529         return dist;
530 }