Another Standalone ITS tracker (E. Crescio)
[u/mrichter/AliRoot.git] / ITS / AliITStrackerSA.cxx
1 /**************************************************************************
2  * Copyright(c) 1998-2003, 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 //  Stand alone tracker class                     //
18 //  Origin:  Elisabetta Crescio                   //
19 //  e-mail:  crescio@to.infn.it                   //
20 //  tracks are saved as AliITStrackV2 objects     //
21 ////////////////////////////////////////////////////
22
23 //#include <stdlib.h>
24 #include "TArrayI.h"
25 #include <TBranch.h>
26 #include <TMath.h>
27 #include <TObjArray.h>
28 #include <TTree.h>
29 #include "AliRun.h"
30 #include "AliITSclusterTable.h"
31 #include "AliITSclusterV2.h"
32 #include "AliITSgeom.h"
33 #include "AliITSRiemannFit.h"
34 #include "AliITStrackerSA.h"
35 #include "AliITStrackSA.h"
36 #include "AliITSVertexer.h"
37 #include "AliITSVertex.h"
38
39
40 ClassImp(AliITStrackerSA)
41
42 //____________________________________________________________________________
43 AliITStrackerSA::AliITStrackerSA():AliITStrackerV2(){
44   // Default constructor
45   Init();
46 }
47 //____________________________________________________________________________
48 AliITStrackerSA::AliITStrackerSA(AliITSgeom *geom, AliITSVertex *vert):AliITStrackerV2(geom) 
49 {
50   // Standard constructor (Vertex is known and passed to this obj.)
51   Init();
52   fVert = vert;
53   fGeom = geom;
54 }
55
56 //______________________________________________________________________
57 AliITStrackerSA::AliITStrackerSA(const AliITStrackerSA &trkr) : 
58                     AliITStrackerV2(trkr) {
59   // Copy constructor
60   // Copies are not allowed. The method is protected to avoid misuse.
61   Error("AliITStrackerSA","Copy constructor not allowed\n");
62 }
63
64 //______________________________________________________________________
65 AliITStrackerSA& AliITStrackerSA::operator=(const 
66                     AliITStrackerSA& /* trkr */){
67   // Assignment operator
68   // Assignment is not allowed. The method is protected to avoid misuse.
69   Error("= operator","Assignment operator not allowed\n");
70   return *this;
71 }
72
73 //____________________________________________________________________________
74 AliITStrackerSA::AliITStrackerSA(AliITSgeom *geom, AliITSVertexer *vertexer):AliITStrackerV2(geom) 
75 {
76   // Standard constructor (Vertex is unknown - vertexer is passed to this obj)
77   Init();
78   fVertexer = vertexer;
79   fGeom = geom;
80 }
81
82 //____________________________________________________________________________
83 AliITStrackerSA::AliITStrackerSA(AliITStrackerSA& tracker):AliITStrackerV2(){
84   // Copy constructor
85   fPhiEstimate = tracker.fPhiEstimate;
86   for(Int_t i=0;i<2;i++){
87     fPoint1[i]=tracker.fPoint1[i];
88     fPoint2[i]=tracker.fPoint2[i];
89     fPoint3[i]=tracker.fPoint3[i];
90     fPointc[i]=tracker.fPointc[i];
91   }
92   fLambdac = tracker.fLambdac;
93   fPhic = tracker.fPhic;
94   fCoef1 = tracker.fCoef1;
95   fCoef2 = tracker.fCoef2;
96   fCoef3 = tracker.fCoef3;
97   fNloop = tracker.fNloop;
98   fPhiWin = tracker.fPhiWin;
99   fLambdaWin = tracker.fLambdaWin;
100   if(tracker.fVertexer && tracker.fVert){
101     fVert = new AliITSVertex(*tracker.fVert);
102   }
103   else {
104     fVert = tracker.fVert;
105   }
106   fVertexer = tracker.fVertexer;
107   fGeom = tracker.fGeom;
108   fFlagLoad = tracker.fFlagLoad;
109   fTable = tracker.fTable;
110 }
111
112 //____________________________________________________________________________
113 AliITStrackerSA::~AliITStrackerSA(){
114   // destructor
115   // if fVertexer is not null, the AliITSVertex obj. is owned by this class
116   // and is deleted here
117   if(fVertexer){
118     if(fVert)delete fVert;
119   }
120   fVert = 0;
121   fVertexer = 0;
122   fGeom = 0;
123   fFlagLoad = 0;
124   if(fPhiWin)delete []fPhiWin;
125   if(fLambdaWin)delete []fLambdaWin;
126   fTable =0;
127 }
128
129 //____________________________________________________________________________
130 void AliITStrackerSA::Init(){
131   //  Reset all data members
132     fPhiEstimate=0;
133     for(Int_t i=0;i<3;i++){fPoint1[i]=0;fPoint2[i]=0;fPoint3[i]=0;}
134     fLambdac=0;
135     fPhic=0;
136     fCoef1=0;
137     fCoef2=0;
138     fCoef3=0;
139     fPointc[0]=0;
140     fPointc[1]=0;
141     fVert = 0;
142     fVertexer = 0;
143     fGeom = 0;
144     fFlagLoad = 0;
145     SetWindowSizes();
146     fTable = 0;
147 }
148 //_______________________________________________________________________
149 void AliITStrackerSA::ResetForFinding(){
150   //  Reset data members used in all loops during track finding
151     fPhiEstimate=0;
152     for(Int_t i=0;i<3;i++){fPoint1[i]=0;fPoint2[i]=0;fPoint3[i]=0;}
153     fLambdac=0;
154     fPhic=0;
155     fCoef1=0;
156     fCoef2=0;
157     fCoef3=0;
158     fPointc[0]=0;
159     fPointc[1]=0;
160 }
161 //____________________________________________________________________________
162 void AliITStrackerSA::FindTracks(TTree *clusterTree, TTree *out,Int_t evnumber,char *opt){
163
164   /**************************************************************************
165    * Options: to use only ITS execute FindTracks                            *
166    *          to define good tracks with 6 points out of 6 in the ITS write *
167    *          *opt="6/6". The default is *opt="6/6"                         *
168    *                                                                        * 
169    *                                                                        *
170    * Example: to execute function with only the ITS (no combined tracking   *
171    *          with TPC+ITS) and requiring 5/6 points to define a good track *
172    *          use: FindTracks(treein,treeout,evnumber,"5/6")                *
173    *          to execute combined tracking, before using FindTracks use     *
174    *          UseFoundTracksV2                                              *
175    *************************************************************************/
176
177   //options
178   TString choice(opt);
179   Bool_t sixpoints= choice.Contains("6/6");
180
181   //Fill array with cluster indices for each module
182   if(!fTable){
183     fTable = new AliITSclusterTable(fGeom,this);
184     fTable->FillArray(clusterTree,evnumber);
185   }
186   //Get primary vertex
187   if(fVertexer){
188     if(fVert)delete fVert;
189     fVert = fVertexer->FindVertexForCurrentEvent(evnumber);
190   }
191   else {
192     gAlice->GetEvent(evnumber);
193     if(!fVert){
194       Fatal("FindTracks","Vertex is missing\n");
195       return;
196     }
197   }
198   Double_t primaryVertex[3];
199   Double_t errorsprimvert[3];
200   fVert->GetXYZ(primaryVertex);
201   fVert->GetSigmaXYZ(errorsprimvert);
202   if(errorsprimvert[0]==0 || errorsprimvert[1]==0){
203     Warning("FindTracks","Set errors on vertex positions x and y at 0.0001");
204     errorsprimvert[0]=0.0001;
205     errorsprimvert[1]=0.0001;
206   }
207   fVert->PrintStatus();
208
209   SetEventNumber(evnumber);
210   if(GetFlagLoadedClusters()==0) LoadClusters(clusterTree);
211    
212 //Fill tree for found tracks
213   AliITStrackV2* outrack=0;
214   TBranch* branch=out->Branch("Tracks","AliITStrackV2",&outrack,32000,0);
215   if (!branch) out->Branch("tracks","AliITStrackV2",&outrack,32000,3);
216   else branch->SetAddress(&outrack);
217
218   
219   Int_t firstmod[fGeom->GetNlayers()];
220   for(Int_t i=0;i<fGeom->GetNlayers();i++){
221     firstmod[i]=fGeom->GetModuleIndex(i+1,1,1);
222   }
223   // firstmod [i] number of the first module in the ITS layer i.
224     
225   AliITSlayer &layer=fgLayers[0];   // first layer
226   Int_t ntrack=0;
227   //loop on the different windows
228   for(Int_t nloop=0;nloop<fNloop;nloop++){
229     Int_t ncl=layer.GetNumberOfClusters();   
230     while(ncl--){ //loop starting from layer 0
231       ResetForFinding();
232       Int_t pflag=0;
233       AliITSclusterV2* cl = layer.GetCluster(ncl);
234       if(cl->IsUsed()==1) continue;     
235       Double_t x,y,z;
236       Int_t module = cl->GetDetectorIndex()+firstmod[0];
237       GetClusterGCoordinates(cl,module,x,y,z);
238       fPhic  = TMath::ATan2(y,x);
239       fLambdac = TMath::ATan2(z-primaryVertex[2],TMath::Sqrt((x-primaryVertex[0])*(x-primaryVertex[0])+(y-primaryVertex[1])*(y-primaryVertex[1])));    
240       fPhiEstimate = fPhic;
241       AliITStrackSA* trs = new AliITStrackSA();      
242       fPoint1[0]=primaryVertex[0];
243       fPoint1[1]=primaryVertex[1];
244       fPoint2[0]=x;
245       fPoint2[1]=y;
246       
247       Int_t nn[fGeom->GetNlayers()];//counter for clusters on each layer
248       for(Int_t i=0;i<fGeom->GetNlayers();i++){ nn[i]=0;}
249       nn[0] = SearchClusters(0,fPhiWin[nloop],fLambdaWin[nloop],trs,primaryVertex[2],primaryVertex[1],primaryVertex[0],pflag,fTable);
250       nn[1] = SearchClusters(1,fPhiWin[nloop],fLambdaWin[nloop],trs,primaryVertex[2],primaryVertex[1],primaryVertex[0],pflag,fTable);
251
252       if(nn[1]>0){
253         pflag=1;
254         fPoint3[0] = fPointc[0];
255         fPoint3[1] = fPointc[1];
256       }
257       nn[2] = SearchClusters(2,fPhiWin[nloop],fLambdaWin[nloop],trs,primaryVertex[2],primaryVertex[1],primaryVertex[0],pflag,fTable);
258       if(nn[1]==0 && nn[2]==0) pflag=0;
259       if(nn[2]!=0 && nn[1]!=0){ pflag=1; UpdatePoints();}
260       if(nn[2]!=0 && nn[1]==0){
261         pflag=1;
262         fPoint3[0]=fPointc[0];
263         fPoint3[1]=fPointc[1];
264       }
265
266       nn[3] = SearchClusters(3,fPhiWin[nloop],fLambdaWin[nloop],trs,primaryVertex[2],primaryVertex[1],primaryVertex[0],pflag,fTable);
267       pflag=1;
268       if(nn[3]!=0) UpdatePoints();
269       nn[4] = SearchClusters(4,fPhiWin[nloop],fLambdaWin[nloop],trs,primaryVertex[2],primaryVertex[1],primaryVertex[0],pflag,fTable); 
270       pflag=1;
271       if(nn[4]!=0) UpdatePoints();
272       nn[5] = SearchClusters(5,fPhiWin[nloop],fLambdaWin[nloop],trs,primaryVertex[2],primaryVertex[1],primaryVertex[0],pflag,fTable); 
273           
274
275       Int_t layOK=0;
276       Int_t numberofpoints;
277       if(sixpoints) numberofpoints=6;  //check of the candidate track
278       else numberofpoints=5;           //if track is good (with the required number        
279       for(Int_t nnp=0;nnp<fGeom->GetNlayers();nnp++){    //of points) it is written on file
280         if(nn[nnp]!=0) layOK+=1;
281       }
282       if(layOK>=numberofpoints){
283         AliITStrackV2* tr2 = FitTrack(trs,primaryVertex,errorsprimvert,opt);
284         if(tr2==0){
285           Int_t nct = trs->GetNumberOfClustersSA();
286           while(nct--){
287             Int_t index = trs->GetClusterIndexSA(nct);
288             AliITSclusterV2* kl = (AliITSclusterV2*)GetCluster(index);
289             if(kl->IsUsed()==1) kl->Use();
290           }
291           continue;
292         }
293         outrack=tr2;  
294         out->Fill();
295         ntrack++;
296         Int_t nct = tr2->GetNumberOfClusters();
297
298         while(nct--){
299           Int_t index = tr2->GetClusterIndex(nct);     
300           AliITSclusterV2* kl = (AliITSclusterV2*)GetCluster(index);      
301           if(kl->IsUsed()==0) kl->Use();
302
303         }
304       } 
305       else{
306         Int_t nct = trs->GetNumberOfClustersSA();
307         while(nct--){
308           Int_t index = trs->GetClusterIndexSA(nct);
309           AliITSclusterV2* kl = (AliITSclusterV2*)GetCluster(index);
310           if(kl->IsUsed()==1) kl->Use();
311         }
312       }
313       delete trs;
314
315     }//end loop on clusters of layer1
316
317   }//end loop2
318
319   //if 5/6 points are required, second loop starting 
320   //from second layer, to find tracks with point of 
321   //layer 1 missing
322    
323   if(!sixpoints){
324     //   counter for clusters on each layer  
325     Int_t *nn = new Int_t[fGeom->GetNlayers()-1];      
326     for(Int_t nloop=0;nloop<fNloop;nloop++){
327       AliITSlayer &layer2=fgLayers[1]; //loop on layer 2
328       Int_t ncl2=layer2.GetNumberOfClusters();
329       while(ncl2--){ //loop starting from layer 2
330         ResetForFinding();
331         Int_t pflag=0;
332         AliITSclusterV2* cl = layer2.GetCluster(ncl2);
333         if(cl->IsUsed()==1) continue;
334         Double_t x,y,z;
335         Int_t module = cl->GetDetectorIndex()+firstmod[1];
336         GetClusterGCoordinates(cl,module,x,y,z);
337         fPhic  = TMath::ATan2(y,x); 
338         fLambdac = TMath::ATan2(z-primaryVertex[2],TMath::Sqrt((x-primaryVertex[0])*(x-primaryVertex[0])+(y-primaryVertex[1])*(y-primaryVertex[1])));       
339
340         fPhiEstimate = fPhic;
341         AliITStrackSA* trs = new AliITStrackSA(); 
342      
343         fPoint1[0]=primaryVertex[0];
344         fPoint1[1]=primaryVertex[1];
345         fPoint2[0]=x;
346         fPoint2[1]=y;
347    
348         for(Int_t kk=0;kk<fGeom->GetNlayers()-1;kk++)nn[kk] = 0;
349         for(Int_t kk=0;kk<fGeom->GetNlayers()-1;kk++){
350           nn[kk] = SearchClusters(kk+1,fPhiWin[nloop],fLambdaWin[nloop],
351                    trs,primaryVertex[2],primaryVertex[1],primaryVertex[0],pflag,fTable);
352           if(nn[kk]==0)break;
353           if(kk>0){
354             UpdatePoints();
355             pflag = 1;
356           }
357         }
358         Int_t fl=0;
359         for(Int_t nnp=0;nnp<fGeom->GetNlayers()-1;nnp++){
360           if(nn[nnp]!=0) fl+=1;
361         }
362         if(fl>=5){  // 5/6       
363           AliITStrackV2* tr2 = FitTrack(trs,primaryVertex,errorsprimvert,opt);
364           if(tr2==0){
365             Int_t nct = trs->GetNumberOfClustersSA();
366             while(nct--){
367               Int_t index = trs->GetClusterIndexSA(nct);
368               AliITSclusterV2* kl = (AliITSclusterV2*)GetCluster(index);
369               if(kl->IsUsed()==1) kl->Use();
370             }
371             continue;
372           }
373           outrack=tr2;
374           out->Fill();
375           Int_t nct = tr2->GetNumberOfClusters();
376           while(nct--){
377             Int_t index = tr2->GetClusterIndex(nct);     
378             AliITSclusterV2* kl = (AliITSclusterV2*)GetCluster(index);
379             if(kl==0) continue;
380             if(kl->IsUsed()==0) kl->Use();
381           }
382         }       
383         else{
384           Int_t nct = trs->GetNumberOfClustersSA();
385           while(nct--){
386             Int_t index = trs->GetClusterIndexSA(nct);
387             AliITSclusterV2* kl = (AliITSclusterV2*)GetCluster(index);
388             if(kl==0) continue;
389             if(kl->IsUsed()==1) kl->Use();
390           }
391         }
392         delete trs;
393       }//end loop on clusters of layer2
394     }
395     delete []nn;
396   }  //end opt="5/6"  
397
398
399   UnloadClusters();
400 }
401 //_______________________________________________________________________
402 void AliITStrackerSA::UseFoundTracksV2(Int_t evnum,TTree* treev2, TTree* clustertree){
403   // Marks as used clusters belonging to tracks found with V2 TPC+ITS tracking
404   if(!fTable){
405     fTable = new AliITSclusterTable(fGeom,this);
406     fTable->FillArray(clustertree,evnum);
407   }
408   LoadClusters(clustertree);
409   SetFlagLoadedClusters(1);
410
411   TBranch* bra = (TBranch*)treev2->GetBranch("tracks");
412   if(!bra) Warning("UseFoundTracksV2","No branch for track tree");
413   AliITStrackV2* ttrrt = new AliITStrackV2;
414   bra->SetAddress(&ttrrt);
415
416   for(Int_t nj=0;nj<treev2->GetEntries();nj++){
417     treev2->GetEvent(nj);
418     Int_t ncl = ttrrt->GetNumberOfClusters();
419     for(Int_t k=0;k<ncl;k++){
420       Int_t index = ttrrt->GetClusterIndex(k);
421       AliITSclusterV2* clui = (AliITSclusterV2*)GetCluster(index);
422       if(clui->IsUsed()==0) clui->Use();  
423     }
424   }
425   delete ttrrt;
426
427 }
428
429 //________________________________________________________________________
430
431 AliITStrackV2* AliITStrackerSA::FitTrack(AliITStrackSA* tr,Double_t *primaryVertex,Double_t *errorsprimvert,char *opt){
432   //fit of the found track
433
434 //options
435   TString choice(opt);
436   Bool_t sixpoints= choice.Contains("6/6");
437   
438   Int_t firstmod[fGeom->GetNlayers()];
439   for(Int_t i=0;i<fGeom->GetNlayers();i++){
440     firstmod[i]=fGeom->GetModuleIndex(i+1,1,1);
441   }  
442   TObjArray* listoftracks=new TObjArray(0,0);
443   AliITStrackV2* otrack2;
444   Int_t nclusters = tr->GetNumberOfClustersSA();
445   TObjArray** listlayer = new TObjArray*[fGeom->GetNlayers()];
446   for(Int_t i=0;i<fGeom->GetNlayers();i++){
447     listlayer[i] = new TObjArray(0,0);
448   }
449
450   TArrayI clind0(20);
451   TArrayI clind1(20);
452   TArrayI clind2(20);
453   TArrayI clind3(20);
454   TArrayI clind4(20);
455   TArrayI clind5(20);
456
457   Int_t nnn[fGeom->GetNlayers()];
458   for(Int_t i=0;i<fGeom->GetNlayers();i++)nnn[i]=0;
459   
460   for(Int_t ncl=0;ncl<nclusters;ncl++){
461     Int_t index = tr->GetClusterIndexSA(ncl);   
462     AliITSclusterV2* cl = (AliITSclusterV2*)GetCluster(index);
463     if(cl->IsUsed()==1) cl->Use();
464     Int_t lay = (index & 0xf0000000) >> 28;
465     if(lay==0) { listlayer[0]->AddLast(cl); clind0[nnn[0]]=index;nnn[0]++;}
466     if(lay==1) { listlayer[1]->AddLast(cl); clind1[nnn[1]]=index;nnn[1]++;}
467     if(lay==2) { listlayer[2]->AddLast(cl); clind2[nnn[2]]=index;nnn[2]++;}
468     if(lay==3) { listlayer[3]->AddLast(cl); clind3[nnn[3]]=index;nnn[3]++;}
469     if(lay==4) { listlayer[4]->AddLast(cl); clind4[nnn[4]]=index;nnn[4]++;}
470     if(lay==5) { listlayer[5]->AddLast(cl); clind5[nnn[5]]=index;nnn[5]++;}    
471   }
472
473  
474   Int_t end[fGeom->GetNlayers()];
475   for(Int_t i=0;i<fGeom->GetNlayers();i++){
476     if(listlayer[i]->GetEntries()==0) end[i]=1;
477     else end[i]=listlayer[i]->GetEntries();
478   }
479
480   for(Int_t l1=0;l1<end[0];l1++){//loop on layer 1
481     AliITSclusterV2* cl0 = (AliITSclusterV2*)listlayer[0]->At(l1); 
482     TVector3** recp = new TVector3*[3];
483     TVector3** errs = new TVector3*[3];
484     recp[0] = new TVector3(primaryVertex[0],primaryVertex[1],primaryVertex[2]);
485     errs[0] = new TVector3(errorsprimvert[0],errorsprimvert[1],errorsprimvert[2]);
486     Double_t x1,y1,z1,sx1,sy1,sz1;
487     Double_t x2,y2,z2,sx2,sy2,sz2;
488     AliITSclusterV2* p1=0;
489     AliITSclusterV2* p2=0;
490
491     for(Int_t l2=0;l2<end[1];l2++){//loop on layer 2
492       AliITSclusterV2* cl1 = (AliITSclusterV2*)listlayer[1]->At(l2);    
493       for(Int_t l3=0;l3<end[2];l3++){  //loop on layer 3
494         AliITSclusterV2* cl2 = (AliITSclusterV2*)listlayer[2]->At(l3);
495
496         if(cl0==0 && cl1!=0) {
497           p2 = cl2;
498           p1=cl1;
499                 
500         }
501         if(cl0!=0 && cl1==0){
502           p1=cl0;
503           p2=cl2;
504         }
505         if(cl0!=0 && cl1!=0){
506           p1=cl0;
507           p2=cl1;
508         }
509         Int_t module1 = p1->GetDetectorIndex()+firstmod[0];
510         Int_t module2 = p2->GetDetectorIndex()+firstmod[1];
511         GetClusterGCoordinates(p1,module1,x1,y1,z1);
512         GetClusterGCoordinates(p2,module2,x2,y2,z2);
513         GetClusterGErrors(p1,module1,sx1,sy1,sz1);
514         GetClusterGErrors(p2,module2,sx2,sy2,sz2);
515         Double_t phi1=TMath::ATan2(y1,x1);
516         recp[1] = new TVector3(x1,y1,z1);
517         errs[1] = new TVector3(sx1,sy1,sz1);
518         recp[2] = new TVector3(x2,y2,z2);
519         errs[2] = new TVector3(sx2,sy2,sz2);
520         
521         //fit on the Riemann sphere
522         Float_t seed1,seed2,seed3;
523         AliITSRiemannFit fit;
524         Int_t rf = fit.FitHelix(3,recp,errs,seed1,seed2,seed3); //this gives phi,tgl,curvature to start Kalman Filter
525         if(rf==0) continue;  
526         Double_t phi=seed1;
527         Double_t tgl=seed2;
528         
529         if(phi1>0){ 
530           if(seed1>-TMath::Pi() && seed1<-0.5*TMath::Pi()){
531             phi=seed1+1.5*TMath::Pi();
532             tgl=seed2; 
533           }
534           if(seed1>-0.5*TMath::Pi() && seed1<0.5*TMath::Pi()){
535             phi=seed1+0.5*TMath::Pi();
536             tgl=(-1)*seed2; 
537           }
538           if(seed1>0.5*TMath::Pi() && seed1<TMath::Pi()){
539             phi=seed1-0.5*TMath::Pi();
540             tgl=seed2; 
541           }
542         }      
543         if(phi1<0){
544           if(seed1>-TMath::Pi() && seed1<-0.5*TMath::Pi()){
545             phi=seed1+0.5*TMath::Pi();
546             tgl=(-1)*seed2; 
547           }
548           if(seed1>-0.5*TMath::Pi() && seed1<0.5*TMath::Pi()){
549             phi=seed1-0.5*TMath::Pi();
550             tgl=seed2; 
551           }
552           if(seed1>0.5*TMath::Pi() && seed1<TMath::Pi()){
553             phi=seed1-1.5*TMath::Pi();
554             tgl=(-1)*seed2; 
555             }
556           }
557         
558         Int_t layer,ladder,detector;
559         fGeom->GetModuleId(module1,layer,ladder,detector);
560         Float_t yclu1 = p1->GetY();
561         Float_t zclu1 = p1->GetZ();
562         Double_t cv=Curvature(primaryVertex[0],primaryVertex[1],x1,y1,x2,y2);
563               
564         for(Int_t l4=0;l4<end[3];l4++){ //loop on layer 4   
565           AliITSclusterV2* cl3 = (AliITSclusterV2*)listlayer[3]->At(l4);
566           for(Int_t l5=0;l5<end[4];l5++){ //loop on layer 5
567             AliITSclusterV2* cl4 = (AliITSclusterV2*)listlayer[4]->At(l5);
568             for(Int_t l6=0;l6<end[5];l6++){ //loop on layer 6  
569               AliITSclusterV2* cl5 = (AliITSclusterV2*)listlayer[5]->At(l6);
570               AliITStrackSA* trac = new AliITStrackSA(layer,ladder,detector,yclu1,zclu1,phi,tgl,cv,1);
571                               
572               if(cl5!=0) trac->AddClusterV2(5,(clind5[l6] & 0x0fffffff)>>0);
573               if(cl4!=0) trac->AddClusterV2(4,(clind4[l5] & 0x0fffffff)>>0);
574               if(cl3!=0) trac->AddClusterV2(3,(clind3[l4] & 0x0fffffff)>>0);
575               if(cl2!=0) trac->AddClusterV2(2,(clind2[l3] & 0x0fffffff)>>0);
576               if(cl1!=0) trac->AddClusterV2(1,(clind1[l2] & 0x0fffffff)>>0);
577               if(cl0!=0) trac->AddClusterV2(0,(clind0[l1] & 0x0fffffff)>>0);
578             
579               //fit with Kalman filter using AliITStrackerV2::RefitAt()
580           
581               AliITStrackV2* ot = new AliITStrackV2(*trac);
582               
583               ot->ResetCovariance();
584               ot->ResetClusters();
585               
586               if(RefitAt(49.,ot,trac)){ //fit from layer 1 to layer 6
587
588                 otrack2 = new AliITStrackV2(*ot);
589                 otrack2->ResetCovariance(); 
590                 otrack2->ResetClusters();
591                 //fit from layer 6 to layer 1
592                 if(RefitAt(3.7,otrack2,ot)) listoftracks->AddLast(otrack2);
593                               
594               }       
595           
596               delete ot;
597               delete trac;
598             }//end loop layer 6
599           }//end loop layer 5
600         }//end loop layer 4
601         
602         for(Int_t i=1;i<3;i++){
603           delete recp[i];
604           delete errs[i];
605         }
606       }//end loop layer 3
607     }//end loop layer 2 
608     delete recp[0];
609     delete errs[0];
610     delete[] recp;
611     delete[] errs;    
612   }//end loop layer 1
613
614   Int_t dim=listoftracks->GetEntries();
615   if(dim==0){
616     delete listoftracks;
617     for(Int_t i=0;i<fGeom->GetNlayers();i++){
618       delete listlayer[i];
619     }
620     delete listlayer;
621     return 0;
622   }
623
624   AliITStrackV2* otrack =(AliITStrackV2*)FindTrackLowChiSquare(listoftracks,dim);
625
626   if(otrack==0) return 0;
627   Int_t indexc[fGeom->GetNlayers()];
628   for(Int_t i=0;i<fGeom->GetNlayers();i++) indexc[i]=0;
629   for(Int_t nind=0;nind<otrack->GetNumberOfClusters();nind++){
630     indexc[nind] = otrack->GetClusterIndex(nind);
631   }      
632   AliITSclusterV2* cl0 = (AliITSclusterV2*)GetCluster(indexc[0]);
633   AliITSclusterV2* cl1 = (AliITSclusterV2*)GetCluster(indexc[1]);     
634   AliITSclusterV2* cl2 = (AliITSclusterV2*)GetCluster(indexc[2]);     
635   AliITSclusterV2* cl3 = (AliITSclusterV2*)GetCluster(indexc[3]);
636   AliITSclusterV2* cl4 = (AliITSclusterV2*)GetCluster(indexc[4]);
637   Int_t labl[3]={-1,-1,-1};
638   if(otrack->GetNumberOfClusters()==fGeom->GetNlayers()){
639     AliITSclusterV2* cl5 = (AliITSclusterV2*)GetCluster(indexc[5]);
640     labl[0]=cl5->GetLabel(0);
641     labl[1]=cl5->GetLabel(1);
642     labl[2]=cl5->GetLabel(2);
643   }
644   if(otrack->GetNumberOfClusters()==(fGeom->GetNlayers()-1)){
645     labl[0]=-1;
646     labl[1]=-1;
647     labl[2]=-1;
648   }
649   Int_t numberofpoints;
650   if(sixpoints) numberofpoints=6;
651   else numberofpoints=5;
652   Int_t label =  Label(cl0->GetLabel(0),cl1->GetLabel(0), 
653                        cl2->GetLabel(0),cl3->GetLabel(0),
654                        cl4->GetLabel(0),labl[0],
655                        cl0->GetLabel(1),cl1->GetLabel(1),
656                        cl2->GetLabel(1),cl3->GetLabel(1),
657                        cl4->GetLabel(1),labl[1],
658                        cl0->GetLabel(2),cl1->GetLabel(2),
659                        cl2->GetLabel(2),cl3->GetLabel(2),
660                        cl4->GetLabel(2),labl[2],numberofpoints);
661   
662   otrack->SetLabel(label);  
663   delete listoftracks;
664   for(Int_t i=0;i<fGeom->GetNlayers();i++){
665     delete listlayer[i];
666   }
667   delete listlayer; 
668   return otrack;
669
670 }
671
672 //________________________________________________________________
673 void AliITStrackerSA::UpdatePoints(){
674   //update of points for the estimation of the curvature  
675
676   fPoint1[0]=fPoint2[0]; 
677   fPoint1[1]=fPoint2[1];
678   fPoint2[0]=fPoint3[0];
679   fPoint2[1]=fPoint3[1];
680   fPoint3[0]=fPointc[0];
681   fPoint3[1]=fPointc[1];
682
683   
684 }
685
686 //_________________________________________________________________
687
688 Int_t AliITStrackerSA::SearchClusters(Int_t layer,Double_t phiwindow,Double_t lambdawindow, AliITStrackSA* trs,Double_t zvertex,Double_t yvertex,Double_t xvertex,Int_t pflag,AliITSclusterTable* table){
689   //function used to to find the clusters associated to the track
690   Int_t nc=0;
691   AliITSlayer &lay = fgLayers[layer];
692   Int_t firstmod[fGeom->GetNlayers()];
693   for(Int_t i=0;i<fGeom->GetNlayers();i++){
694     firstmod[i]=fGeom->GetModuleIndex(i+1,1,1);
695   }
696   if(pflag==1){
697       
698     Float_t cx1,cx2,cy1,cy2;
699     FindEquation(fPoint1[0],fPoint1[1],fPoint2[0],fPoint2[1],fPoint3[0],fPoint3[1],fCoef1,fCoef2,fCoef3);
700     Int_t fun = FindIntersection(fCoef1,fCoef2,fCoef3,-(lay.GetR()*lay.GetR()),cx1,cy1,cx2,cy2);
701     if(fun==0) return 0;
702     Double_t fi1 =TMath::ATan2(cy1,cx1);
703     Double_t fi2 =TMath::ATan2(cy2,cx2);
704     fPhiEstimate = ChoosePoint(fi1,fi2,fPhic);
705   }
706
707   Double_t zed = TMath::Tan(fLambdac)*lay.GetR()+zvertex;
708   Double_t zed1  =  TMath::Tan(fLambdac+lambdawindow)*lay.GetR()+zvertex;
709   Double_t zed2  =  TMath::Tan(fLambdac-lambdawindow)*lay.GetR()+zvertex;
710   
711   Double_t fi = fPhiEstimate;
712   Int_t nmod  = lay.FindDetectorIndex(fi,zed)+firstmod[layer];
713  
714   Int_t nm[8]={0,0,0,0,0,0,0,0};
715   nm[0] = lay.FindDetectorIndex(fi+phiwindow,zed)+firstmod[layer];
716   nm[1] = lay.FindDetectorIndex(fi-phiwindow,zed)+firstmod[layer];
717   nm[2]  = lay.FindDetectorIndex(fi,zed1)+firstmod[layer];
718   nm[3]  = lay.FindDetectorIndex(fi,zed2)+firstmod[layer];
719   nm[4]  = lay.FindDetectorIndex(fi+phiwindow,zed1)+firstmod[layer];
720   nm[5]  = lay.FindDetectorIndex(fi-phiwindow,zed1)+firstmod[layer];
721   nm[6]  = lay.FindDetectorIndex(fi+phiwindow,zed2)+firstmod[layer];
722   nm[7]  = lay.FindDetectorIndex(fi-phiwindow,zed2)+firstmod[layer];
723
724  
725    if(nmod<0) return 0;
726   Int_t nn=0;
727   TArrayI* array =(TArrayI*)table->GetListOfClusters(nmod);
728   TArrayI* list = new TArrayI(array->GetSize());
729   for(Int_t i=0;i<array->GetSize();i++){
730     Int_t in=(Int_t)array->At(i);
731     list->AddAt(in,nn);
732     nn++;
733   }
734   
735   for(Int_t ii=0;ii<8;ii++){
736     if(nm[ii]!=nmod && nm[ii]>=0){
737       TArrayI* ar =(TArrayI*)table->GetListOfClusters(nm[ii]);
738       list->Set(list->GetSize()+ar->GetSize());
739       for(Int_t j=0;j<ar->GetSize();j++){
740         Int_t in=(Int_t)ar->At(j);
741         list->AddAt(in,nn);
742         nn++;
743       }
744     }
745   }
746   for(Int_t i=0;i<list->GetSize();i++){
747     Int_t index = (Int_t)list->At(i);
748     AliITSclusterV2* cllay = lay.GetCluster(index);
749     if(cllay==0) continue;
750     if(cllay->IsUsed()==1) continue;
751     
752     Double_t x,y,z;
753     Int_t modlay = cllay->GetDetectorIndex()+firstmod[layer];
754     GetClusterGCoordinates(cllay,modlay,x,y,z);
755     Double_t phi   = TMath::ATan2(y,x);
756     Double_t lambda=TMath::ATan2(z-zvertex,TMath::Sqrt((x-xvertex)*(x-xvertex)+(y-yvertex)*(y-yvertex)));
757
758
759     if(TMath::Abs(fLambdac-lambda)<lambdawindow && 
760        TMath::Abs(fPhiEstimate-phi)<phiwindow){
761       nc+=1;
762       fLambdac = lambda;
763       if(trs->GetNumberOfClustersSA()==20){
764         delete list;
765         return 0;
766       }
767       trs->AddClusterSA(layer,index);
768       cllay->Use();
769       fPhiEstimate=phi;
770       fPointc[0]=x;fPointc[1]=y;
771     }
772
773   }
774   delete list;
775   return nc;
776
777 }
778
779 //__________________________________________________________________
780 void AliITStrackerSA::GetClusterGCoordinates(AliITSclusterV2* cluster,Int_t module,Double_t& x, Double_t& y, Double_t& z){
781
782   //returns x,y,z of cluster in global coordinates
783
784   Double_t rot[9];     fGeom->GetRotMatrix(module,rot);
785   Int_t lay,lad,det; fGeom->GetModuleId(module,lay,lad,det);
786   Float_t tx,ty,tz;  fGeom->GetTrans(lay,lad,det,tx,ty,tz);     
787
788   Double_t alpha=TMath::ATan2(rot[1],rot[0])+TMath::Pi();
789   Double_t phi=TMath::Pi()/2+alpha;
790   if (lay==1) phi+=TMath::Pi();
791
792   Double_t cp=TMath::Cos(phi), sp=TMath::Sin(phi);
793   Double_t r=tx*cp+ty*sp;
794
795   x= r*cp - cluster->GetY()*sp;
796   y= r*sp + cluster->GetY()*cp;
797   z=cluster->GetZ();
798
799   
800
801 }
802 //__________________________________________________________________
803 void AliITStrackerSA::GetClusterGErrors(AliITSclusterV2* cluster,Int_t module,Double_t& sigmax, Double_t& sigmay, Double_t& sigmaz){
804
805   //returns x,y,z of cluster in global coordinates
806
807   Double_t rot[9];     fGeom->GetRotMatrix(module,rot);
808   Int_t lay,lad,det; fGeom->GetModuleId(module,lay,lad,det);
809  
810   Double_t alpha=TMath::ATan2(rot[1],rot[0])+TMath::Pi();
811   Double_t phi=TMath::Pi()/2+alpha;
812   if (lay==1) phi+=TMath::Pi();
813
814   Double_t cp=TMath::Cos(phi), sp=TMath::Sin(phi);
815
816  
817   sigmax = TMath::Sqrt(sp*sp*cluster->GetSigmaY2());
818   sigmay = TMath::Sqrt(cp*cp*cluster->GetSigmaY2());
819   sigmaz = TMath::Sqrt(cluster->GetSigmaZ2());
820 }
821
822 //___________________________________________________________________
823 Int_t AliITStrackerSA::FindEquation(Float_t x1, Float_t y1, Float_t x2, Float_t y2, Float_t x3, Float_t y3,Float_t& a, Float_t& b, Float_t& c){
824
825    //given (x,y) of three recpoints (in global coordinates) 
826    //returns the parameters a,b,c of circonference x*x + y*y +a*x + b*y +c
827
828    Float_t den = (x3-x1)*(y2-y1)-(x2-x1)*(y3-y1);
829    if(den==0) return 0;
830    a = ((y3-y1)*(x2*x2+y2*y2-x1*x1-y1*y1)-(y2-y1)*(x3*x3+y3*y3-x1*x1-y1*y1))/den;
831    b = -(x2*x2-x1*x1+y2*y2-y1*y1+a*(x2-x1))/(y2-y1);
832    c = -x1*x1-y1*y1-a*x1-b*y1;
833    return 1;
834  }
835 //__________________________________________________________________________
836  Int_t AliITStrackerSA::FindIntersection(Float_t a1, Float_t b1, Float_t c1, Float_t c2,Float_t& x1,Float_t& y1, Float_t& x2, Float_t& y2){
837  
838  //Finds the intersection between the circonference of the track and the circonference centered in (0,0) represented by one layer
839  //c2 is -rlayer*rlayer
840
841   if(a1==0) return 0;
842  Float_t m = c2-c1; 
843  Float_t aA = (b1*b1)/(a1*a1)+1;
844  Float_t bB = (-2*m*b1/(a1*a1));
845  Float_t cC = c2+(m*m)/(a1*a1);
846  if((bB*bB-4*aA*cC)<0) return 0;
847  
848  y1 = (-bB+TMath::Sqrt(bB*bB-4*aA*cC))/(2*aA); 
849  y2 = (-bB-TMath::Sqrt(bB*bB-4*aA*cC))/(2*aA); 
850  x1 = (c2-c1-b1*y1)/a1;
851  x2 = (c2-c1-b1*y2)/a1;
852
853  return 1; 
854 }
855 //____________________________________________________________________
856 Double_t AliITStrackerSA::Curvature(Double_t x1,Double_t y1,Double_t 
857 x2,Double_t y2,Double_t x3,Double_t y3){
858
859   //calculates the curvature of track  
860   Double_t den = (x3-x1)*(y2-y1)-(x2-x1)*(y3-y1);
861   if(den==0) return 0;
862   Double_t a = ((y3-y1)*(x2*x2+y2*y2-x1*x1-y1*y1)-(y2-y1)*(x3*x3+y3*y3-x1*x1-y1*y1))/den;
863   Double_t b = -(x2*x2-x1*x1+y2*y2-y1*y1+a*(x2-x1))/(y2-y1);
864   Double_t c = -x1*x1-y1*y1-a*x1-b*y1;
865   Double_t xc=-a/2.;
866
867   if((a*a+b*b-4*c)<0) return 0;
868   Double_t rad = TMath::Sqrt(a*a+b*b-4*c)/2.;
869   if(rad==0) return 0;
870   
871   if((x1>0 && y1>0 && x1<xc)) rad*=-1;
872   if((x1<0 && y1>0 && x1<xc)) rad*=-1;
873   //  if((x1<0 && y1<0 && x1<xc)) rad*=-1;
874   // if((x1>0 && y1<0 && x1<xc)) rad*=-1;
875   
876   return 1/rad;
877  
878 }
879 //____________________________________________________________________
880 Double_t AliITStrackerSA::ChoosePoint(Double_t p1, Double_t p2, Double_t pp){
881
882   //Returns the point closest to pp
883
884   Double_t diff1 = p1-pp;
885   Double_t diff2 = p2-pp;
886   
887   if(TMath::Abs(diff1)<TMath::Abs(diff2)) fPhiEstimate=p1;
888   else fPhiEstimate=p2;  
889   return fPhiEstimate;
890   
891 }
892
893
894 //_________________________________________________________________
895 AliITStrackV2* AliITStrackerSA::FindTrackLowChiSquare(TObjArray* tracklist, Int_t dim) const {
896   // returns track with lowes chi square  
897   if(dim==1){
898     AliITStrackV2* trk = (AliITStrackV2*)tracklist->At(0);
899     return trk;
900   }
901   if(dim==0) return 0;
902   Double_t chi2[dim];
903   Int_t index[dim];
904   for(Int_t i=0;i<dim;i++){
905     AliITStrackV2* trk = (AliITStrackV2*)tracklist->At(i);
906     chi2[i]=trk->GetChi2();
907     index[i]=i;
908   }
909
910   Int_t w=0;Double_t value;
911   Int_t lp;
912   while(w<dim){
913     for(Int_t j=w+1;j<dim;j++){
914       if(chi2[w]<chi2[j]){
915         value=chi2[w];
916         chi2[w]=chi2[j];
917         chi2[j]=value;
918         lp=index[w];
919         index[w]=index[j];
920         index[j]=lp;
921       }
922     }
923     w++;
924   }
925
926   AliITStrackV2* trk = (AliITStrackV2*)tracklist->At(index[dim-1]);
927   return trk;
928   
929 }
930
931 //__________________________________________________________
932 Int_t AliITStrackerSA::FindLabel(Int_t l1, Int_t l2, Int_t l3, Int_t l4, Int_t l5, Int_t l6){
933
934   //function used to determine the track label
935   
936   Int_t lb[6] = {l1,l2,l3,l4,l5,l6};
937   Int_t aa[6]={1,1,1,1,1,1};
938   Int_t ff=0; 
939   Int_t ll=0;
940   Int_t k=0;Int_t w=0;Int_t num=6;
941   if(lb[5]==-1) num=5;
942   
943   while(k<num){
944   
945     for(Int_t i=k+1;i<num;i++){
946     
947       if(lb[k]==lb[i] && aa[k]!=0){
948       
949         aa[k]+=1;
950         aa[i]=0;
951       }
952     }
953   k++;
954   }
955
956   while(w<num){
957   
958     for(Int_t j=0;j<6;j++){
959       if(aa[w]<aa[j]){
960       ff=aa[w];
961       aa[w]=aa[j];
962       aa[j]=ff;
963       ll=lb[w];
964       lb[w]=lb[j];
965       lb[j]=ll;
966      }
967     }
968   w++;
969   }
970   if(num==6)  return lb[5];
971   else return lb[4];
972 }
973
974 //_____________________________________________________________________________
975 Int_t AliITStrackerSA::Label(Int_t gl1, Int_t gl2, Int_t gl3, Int_t gl4, Int_t gl5, Int_t gl6,Int_t gl7, Int_t gl8, Int_t gl9, Int_t gl10,Int_t gl11,
976 Int_t gl12, Int_t gl13, Int_t gl14,Int_t gl15, Int_t gl16, Int_t gl17, Int_t gl18, Int_t numberofpoints){
977
978  
979   //function used to assign label to the found track. If track is fake, the label is negative
980
981   Int_t lb0[6] = {gl1,gl2,gl3,gl4,gl5,gl6};
982   Int_t lb1[6] = {gl7,gl8,gl9,gl10,gl11,gl12};
983   Int_t lb2[6] = {gl13,gl14,gl15,gl16,gl17,gl18};
984   Int_t ll=FindLabel(lb0[0],lb0[1],lb0[2],lb0[3],lb0[4],lb0[5]);
985   Int_t lflag=0;Int_t num=6;
986   if(lb0[5]==-1 && lb1[5]==-1 && lb2[5]==-1) num=5;
987
988   for(Int_t i=0;i<num;i++){
989     if(lb0[i]==ll || lb1[i]==ll || lb2[i]==ll) lflag+=1;
990   }
991
992   if(lflag>=numberofpoints) return ll;
993   else return -ll;
994
995   
996 }
997
998 //_____________________________________________________________________________
999 void AliITStrackerSA::SetWindowSizes(Int_t n, Double_t *phi, Double_t *lam){
1000   // Set sizes of the phi and lambda windows used for track finding
1001   fNloop = n;
1002   if(phi){ // user defined values
1003     fPhiWin = new Double_t[fNloop];
1004     fLambdaWin = new Double_t[fNloop];
1005     for(Int_t k=0;k<fNloop;k++){
1006       fPhiWin[k]=phi[k];
1007       fLambdaWin[k]=lam[k];
1008     }
1009   }
1010   else {  // default values
1011     Double_t phid[46]   = {0.001,0.0015,0.002,0.0023,0.0025,0.0027,0.003,
1012                         0.0033,0.0035,0.0037,0.004,0.0043,0.0045,0.0047,
1013                         0.005,0.0053,0.0055,
1014                         0.006,0.0063,0.0065,0.007,0.0073,0.0075,0.0077,
1015                         0.008,0.0083,0.0085,0.0087,0.009,0.0095,0.0097,
1016                         0.01,0.0105,0.011,0.0115,0.012,0.0125,0.013,0.0135,
1017                         0.014,0.0145,0.015,0.0155,0.016,0.0165,0.017};
1018     Double_t lambdad[46] = {0.001,0.0015,0.002,0.0023,0.0025,0.0027,0.003,
1019                         0.0033,0.0035,0.0037,0.004,0.0043,0.0045,0.0047,
1020                         0.005,0.0053,0.0055,
1021                         0.006,0.0063,0.0065,0.007,0.0073,0.0075,0.0077,
1022                         0.008,0.0083,0.0085,0.0087,0.009,0.0095,0.0097,
1023                         0.01,0.015,0.011,0.0115,0.012,0.0125,0.013,0.0135,
1024                         0.014,0.0145,0.015,0.0155,0.016,0.016,0.016};
1025     if(fNloop!=46){
1026       fNloop = 46;
1027       Warning("SetWindowSizes","Number of loop forced to the default value %d",fNloop);
1028     }
1029    
1030     fPhiWin = new Double_t[fNloop];
1031     fLambdaWin = new Double_t[fNloop];
1032    
1033     for(Int_t k=0;k<fNloop;k++){
1034       fPhiWin[k]=phid[k];
1035       fLambdaWin[k]=lambdad[k];
1036     }
1037   
1038   }
1039
1040 }
1041  
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