Enlarging the recoParam functionality and populating the track list (needed by HLT)
[u/mrichter/AliRoot.git] / TRD / AliTRDseedV1.cxx
1 /**************************************************************************
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3  *                                                                        *
4  * Author: The ALICE Off-line Project.                                    *
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15
16 /* $Id$ */
17
18 ////////////////////////////////////////////////////////////////////////////
19 //                                                                        //
20 //  The TRD track seed                                                    //
21 //                                                                        //
22 //  Authors:                                                              //
23 //    Alex Bercuci <A.Bercuci@gsi.de>                                     //
24 //    Markus Fasel <M.Fasel@gsi.de>                                       //
25 //                                                                        //
26 ////////////////////////////////////////////////////////////////////////////
27
28 #include "TMath.h"
29 #include "TLinearFitter.h"
30 #include "TClonesArray.h" // tmp
31 #include <TTreeStream.h>
32
33 #include "AliLog.h"
34 #include "AliMathBase.h"
35
36 #include "AliTRDcluster.h"
37 #include "AliTRDseedV1.h"
38 #include "AliTRDtrackV1.h"
39 #include "AliTRDcalibDB.h"
40 #include "AliTRDchamberTimeBin.h"
41 #include "AliTRDtrackingChamber.h"
42 #include "AliTRDtrackerV1.h"
43 #include "AliTRDReconstructor.h"
44 #include "AliTRDrecoParam.h"
45 #include "AliTRDgeometry.h"
46 #include "Cal/AliTRDCalPID.h"
47
48 ClassImp(AliTRDseedV1)
49
50 //____________________________________________________________________
51 AliTRDseedV1::AliTRDseedV1(Int_t plane) 
52   :AliTRDseed()
53   ,fPlane(plane)
54   ,fMom(0.)
55   ,fSnp(0.)
56   ,fTgl(0.)
57   ,fdX(0.)
58 {
59   //
60   // Constructor
61   //
62         for(int islice=0; islice < knSlices; islice++) fdEdx[islice] = 0.;
63         for(int ispec=0; ispec<AliPID::kSPECIES; ispec++) fProb[ispec]  = -1.;
64 }
65
66 //____________________________________________________________________
67 AliTRDseedV1::AliTRDseedV1(const AliTRDseedV1 &ref)
68   :AliTRDseed((AliTRDseed&)ref)
69   ,fPlane(ref.fPlane)
70   ,fMom(ref.fMom)
71   ,fSnp(ref.fSnp)
72   ,fTgl(ref.fTgl)
73   ,fdX(ref.fdX)
74 {
75   //
76   // Copy Constructor performing a deep copy
77   //
78
79         //AliInfo("");
80         for(int islice=0; islice < knSlices; islice++) fdEdx[islice] = ref.fdEdx[islice];
81         for(int ispec=0; ispec<AliPID::kSPECIES; ispec++) fProb[ispec] = ref.fProb[ispec];
82 }
83
84
85 //____________________________________________________________________
86 AliTRDseedV1& AliTRDseedV1::operator=(const AliTRDseedV1 &ref)
87 {
88   //
89   // Assignment Operator using the copy function
90   //
91
92         //AliInfo("");
93         if(this != &ref){
94                 ref.Copy(*this);
95         }
96         return *this;
97
98 }
99
100 //____________________________________________________________________
101 AliTRDseedV1::~AliTRDseedV1()
102 {
103   //
104   // Destructor. The RecoParam object belongs to the underlying tracker.
105   //
106
107         //AliInfo(Form("fOwner[%s]", fOwner?"YES":"NO"));
108
109         if(IsOwner()) 
110                 for(int itb=0; itb<knTimebins; itb++){
111                         if(!fClusters[itb]) continue; 
112                         //AliInfo(Form("deleting c %p @ %d", fClusters[itb], itb));
113                         delete fClusters[itb];
114                         fClusters[itb] = 0x0;
115                 }
116 }
117
118 //____________________________________________________________________
119 void AliTRDseedV1::Copy(TObject &ref) const
120 {
121   //
122   // Copy function
123   //
124
125         //AliInfo("");
126         AliTRDseedV1 &target = (AliTRDseedV1 &)ref; 
127         
128         target.fPlane         = fPlane;
129         target.fMom           = fMom;
130         target.fSnp           = fSnp;
131         target.fTgl           = fTgl;
132         target.fdX            = fdX;
133         
134         for(int islice=0; islice < knSlices; islice++) target.fdEdx[islice] = fdEdx[islice];
135         for(int ispec=0; ispec<AliPID::kSPECIES; ispec++) target.fProb[ispec] = fProb[ispec];
136         
137         AliTRDseed::Copy(target);
138 }
139
140
141 //____________________________________________________________
142 Bool_t AliTRDseedV1::Init(AliTRDtrackV1 *track)
143 {
144 // Initialize this tracklet using the track information
145 //
146 // Parameters:
147 //   track - the TRD track used to initialize the tracklet
148 // 
149 // Detailed description
150 // The function sets the starting point and direction of the
151 // tracklet according to the information from the TRD track.
152 // 
153 // Caution
154 // The TRD track has to be propagated to the beginning of the
155 // chamber where the tracklet will be constructed
156 //
157
158         Double_t y, z; 
159         if(!track->GetProlongation(fX0, y, z)) return kFALSE;
160         fYref[0] = y;
161         fYref[1] = track->GetSnp()/(1. - track->GetSnp()*track->GetSnp());
162         fZref[0] = z;
163         fZref[1] = track->GetTgl();
164
165         //printf("Tracklet ref x[%7.3f] y[%7.3f] z[%7.3f], snp[%f] tgl[%f]\n", fX0, fYref[0], fZref[0], track->GetSnp(), track->GetTgl());
166         return kTRUE;
167 }
168
169
170 //____________________________________________________________________
171 void AliTRDseedV1::CookdEdx(Int_t nslices)
172 {
173 // Calculates average dE/dx for all slices and store them in the internal array fdEdx. 
174 //
175 // Parameters:
176 //  nslices : number of slices for which dE/dx should be calculated
177 // Output:
178 //  store results in the internal array fdEdx. This can be accessed with the method
179 //  AliTRDseedV1::GetdEdx()
180 //
181 // Detailed description
182 // Calculates average dE/dx for all slices. Depending on the PID methode 
183 // the number of slices can be 3 (LQ) or 8(NN). 
184 // The calculation of dQ/dl are done using the tracklet fit results (see AliTRDseedV1::GetdQdl(Int_t)) i.e.
185 //
186 // dQ/dl = qc/(dx * sqrt(1 + dy/dx^2 + dz/dx^2))
187 //
188 // The following effects are included in the calculation:
189 // 1. calibration values for t0 and vdrift (using x coordinate to calculate slice)
190 // 2. cluster sharing (optional see AliTRDrecoParam::SetClusterSharing())
191 // 3. cluster size
192 //
193
194         Int_t nclusters[knSlices];
195         for(int i=0; i<knSlices; i++){ 
196                 fdEdx[i]     = 0.;
197                 nclusters[i] = 0;
198         }
199         Float_t clength = (/*.5 * */AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
200
201         AliTRDcluster *cluster = 0x0;
202         for(int ic=0; ic<AliTRDtrackerV1::GetNTimeBins(); ic++){
203                 if(!(cluster = fClusters[ic])) continue;
204                 Float_t x = cluster->GetX();
205                 
206                 // Filter clusters for dE/dx calculation
207                 
208                 // 1.consider calibration effects for slice determination
209                 Int_t slice; 
210                 if(cluster->IsInChamber()) slice = Int_t(TMath::Abs(fX0 - x) * nslices / clength);
211                 else slice = x < fX0 ? 0 : nslices-1;
212                 
213                 // 2. take sharing into account
214                 Float_t w = cluster->IsShared() ? .5 : 1.;
215                 
216                 // 3. take into account large clusters TODO
217                 //w *= c->GetNPads() > 3 ? .8 : 1.;
218                 
219                 //CHECK !!!
220                 fdEdx[slice]   += w * GetdQdl(ic); //fdQdl[ic];
221                 nclusters[slice]++;
222         } // End of loop over clusters
223
224         if(AliTRDReconstructor::RecoParam()->GetPIDMethod() == 0){
225         // calculate mean charge per slice (only LQ PID)
226                 for(int is=0; is<nslices; is++){ 
227             if(nclusters[is]) fdEdx[is] /= nclusters[is];
228           }
229         }
230 }
231
232
233 //____________________________________________________________________
234 Float_t AliTRDseedV1::GetdQdl(Int_t ic) const
235 {
236         return fClusters[ic] ? TMath::Abs(fClusters[ic]->GetQ()) /fdX / TMath::Sqrt(1. + fYfit[1]*fYfit[1] + fZref[1]*fZref[1]) : 0.;
237 }
238
239 //____________________________________________________________________
240 Double_t* AliTRDseedV1::GetProbability()
241 {       
242 // Fill probability array for tracklet from the DB.
243 //
244 // Parameters
245 //
246 // Output
247 //   returns pointer to the probability array and 0x0 if missing DB access 
248 //
249 // Detailed description
250
251         
252         // retrive calibration db
253   AliTRDcalibDB *calibration = AliTRDcalibDB::Instance();
254   if (!calibration) {
255     AliError("No access to calibration data");
256     return 0x0;
257   }
258
259   // Retrieve the CDB container class with the parametric detector response
260   const AliTRDCalPID *pd = calibration->GetPIDObject(AliTRDReconstructor::RecoParam()->GetPIDMethod());
261   if (!pd) {
262     AliError("No access to AliTRDCalPID object");
263     return 0x0;
264   }
265         //AliInfo(Form("Method[%d] : %s", AliTRDReconstructor::RecoParam()->GetPIDMethod(), pd->IsA()->GetName()));
266
267         // calculate tracklet length TO DO
268   Float_t length = (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
269   /// TMath::Sqrt((1.0 - fSnp[iPlane]*fSnp[iPlane]) / (1.0 + fTgl[iPlane]*fTgl[iPlane]));
270   
271   //calculate dE/dx
272   CookdEdx(AliTRDReconstructor::RecoParam()->GetNdEdxSlices());
273   
274   // Sets the a priori probabilities
275   for(int ispec=0; ispec<AliPID::kSPECIES; ispec++) {
276     fProb[ispec] = pd->GetProbability(ispec, fMom, &fdEdx[0], length, fPlane);  
277   }
278
279         return &fProb[0];
280 }
281
282 //____________________________________________________________________
283 Float_t AliTRDseedV1::GetQuality(Bool_t kZcorr) const
284 {
285   //
286   // Returns a quality measurement of the current seed
287   //
288
289         Float_t zcorr = kZcorr ? fTilt * (fZProb - fZref[0]) : 0.;
290         return 
291                   .5 * TMath::Abs(18.0 - fN2)
292                 + 10.* TMath::Abs(fYfit[1] - fYref[1])
293                 + 5. * TMath::Abs(fYfit[0] - fYref[0] + zcorr)
294                 + 2. * TMath::Abs(fMeanz - fZref[0]) / fPadLength;
295 }
296
297 //____________________________________________________________________
298 void AliTRDseedV1::GetCovAt(Double_t /*x*/, Double_t *cov) const
299 {
300 // Computes covariance in the y-z plane at radial point x
301
302         Int_t ic = 0; while (!fClusters[ic]) ic++; 
303   AliTRDcalibDB *fCalib = AliTRDcalibDB::Instance();
304         Double_t exB         = fCalib->GetOmegaTau(fCalib->GetVdriftAverage(fClusters[ic]->GetDetector()), -AliTracker::GetBz()*0.1);
305
306         Double_t sy2    = fSigmaY2*fSigmaY2 + .2*(fYfit[1]-exB)*(fYfit[1]-exB);
307         Double_t sz2    = fPadLength/12.;
308
309
310         //printf("Yfit[1] %f sy20 %f SigmaY2 %f\n", fYfit[1], sy20, fSigmaY2);
311
312         cov[0] = sy2;
313         cov[1] = fTilt*(sy2-sz2);
314         cov[2] = sz2;
315 }
316
317
318 //____________________________________________________________________
319 void AliTRDseedV1::SetOwner(Bool_t own)
320 {
321         //AliInfo(Form("own [%s] fOwner[%s]", own?"YES":"NO", fOwner?"YES":"NO"));
322         
323         if(own){
324                 for(int ic=0; ic<knTimebins; ic++){
325                         if(!fClusters[ic]) continue;
326                         fClusters[ic] = new AliTRDcluster(*fClusters[ic]);
327                 }
328                 SetBit(1);
329         } else {
330                 if(IsOwner()){
331                         for(int ic=0; ic<knTimebins; ic++){
332                                 if(!fClusters[ic]) continue;
333                                 delete fClusters[ic];
334                                 //fClusters[ic] = tracker->GetClusters(index) TODO
335                         }
336                 }
337                 SetBit(1, kFALSE);
338         }
339 }
340
341 //____________________________________________________________________
342 Bool_t  AliTRDseedV1::AttachClustersIter(AliTRDtrackingChamber *chamber, Float_t quality, Bool_t kZcorr, AliTRDcluster *c)
343 {
344   //
345   // Iterative process to register clusters to the seed.
346   // In iteration 0 we try only one pad-row and if quality not
347   // sufficient we try 2 pad-rows (about 5% of tracks cross 2 pad-rows)
348   //
349         // debug level 7
350         //
351         
352         if(!AliTRDReconstructor::RecoParam()){
353                 AliError("Seed can not be used without a valid RecoParam.");
354                 return kFALSE;
355         }
356
357         AliTRDchamberTimeBin *layer = 0x0;
358         if(AliTRDReconstructor::RecoParam()->GetStreamLevel()>=7 && c){
359                 TClonesArray clusters("AliTRDcluster", 24);
360                 clusters.SetOwner(kTRUE);
361                 AliTRDcluster *cc = 0x0;
362                 Int_t det=-1, ncl, ncls = 0;
363                 for (Int_t iTime = 0; iTime < AliTRDtrackerV1::GetNTimeBins(); iTime++) {
364                         if(!(layer = chamber->GetTB(iTime))) continue;
365                         if(!(ncl = Int_t(*layer))) continue;
366                         for(int ic=0; ic<ncl; ic++){ 
367                                 cc = (*layer)[ic];
368                                 det = cc->GetDetector();
369                                 new(clusters[ncls++]) AliTRDcluster(*cc);
370                         }
371                 }
372                 AliInfo(Form("N clusters[%d] = %d", fPlane, ncls));
373                 
374                 Int_t ref = c ? 1 : 0;
375                 TTreeSRedirector &cstreamer = *AliTRDtrackerV1::DebugStreamer();
376                 cstreamer << "AttachClustersIter"
377                         << "det="        << det 
378                         << "ref="        << ref 
379                         << "clusters.="  << &clusters
380                         << "tracklet.="  << this
381                         << "cl.="        << c
382                         << "\n";        
383         }
384
385         Float_t  tquality;
386         Double_t kroady = AliTRDReconstructor::RecoParam()->GetRoad1y();
387         Double_t kroadz = fPadLength * .5 + 1.;
388         
389         // initialize configuration parameters
390         Float_t zcorr = kZcorr ? fTilt * (fZProb - fZref[0]) : 0.;
391         Int_t   niter = kZcorr ? 1 : 2;
392         
393         Double_t yexp, zexp;
394         Int_t ncl = 0;
395         // start seed update
396         for (Int_t iter = 0; iter < niter; iter++) {
397                 ncl = 0;
398                 for (Int_t iTime = 0; iTime < AliTRDtrackerV1::GetNTimeBins(); iTime++) {
399                         if(!(layer = chamber->GetTB(iTime))) continue;
400                         if(!Int_t(*layer)) continue;
401                         
402                         // define searching configuration
403                         Double_t dxlayer = layer->GetX() - fX0;
404                         if(c){
405                                 zexp = c->GetZ();
406                                 //Try 2 pad-rows in second iteration
407                                 if (iter > 0) {
408                                         zexp = fZref[0] + fZref[1] * dxlayer - zcorr;
409                                         if (zexp > c->GetZ()) zexp = c->GetZ() + fPadLength*0.5;
410                                         if (zexp < c->GetZ()) zexp = c->GetZ() - fPadLength*0.5;
411                                 }
412                         } else zexp = fZref[0] + (kZcorr ? fZref[1] * dxlayer : 0.);
413                         yexp  = fYref[0] + fYref[1] * dxlayer - zcorr;
414                         
415                         // Get and register cluster
416                         Int_t    index = layer->SearchNearestCluster(yexp, zexp, kroady, kroadz);
417                         if (index < 0) continue;
418                         AliTRDcluster *cl = (*layer)[index];
419                         
420                         fIndexes[iTime]  = layer->GetGlobalIndex(index);
421                         fClusters[iTime] = cl;
422                         fY[iTime]        = cl->GetY();
423                         fZ[iTime]        = cl->GetZ();
424                         ncl++;
425                 }
426         if(AliTRDReconstructor::RecoParam()->GetStreamLevel()>=7) AliInfo(Form("iter = %d ncl [%d] = %d", iter, fPlane, ncl));
427                 
428                 if(ncl>1){      
429                         // calculate length of the time bin (calibration aware)
430                         Int_t irp = 0; Float_t x[2]; Int_t tb[2];
431                         for (Int_t iTime = 0; iTime < AliTRDtrackerV1::GetNTimeBins(); iTime++) {
432                                 if(!fClusters[iTime]) continue;
433                                 x[irp]  = fClusters[iTime]->GetX();
434                                 tb[irp] = iTime;
435                                 irp++;
436                                 if(irp==2) break;
437                         } 
438                         fdX = (x[1] - x[0]) / (tb[0] - tb[1]);
439         
440                         // update X0 from the clusters (calibration/alignment aware)
441                         for (Int_t iTime = 0; iTime < AliTRDtrackerV1::GetNTimeBins(); iTime++) {
442                                 if(!(layer = chamber->GetTB(iTime))) continue;
443                                 if(!layer->IsT0()) continue;
444                                 if(fClusters[iTime]){ 
445                                         fX0 = fClusters[iTime]->GetX();
446                                         break;
447                                 } else { // we have to infere the position of the anode wire from the other clusters
448                                         for (Int_t jTime = iTime+1; jTime < AliTRDtrackerV1::GetNTimeBins(); jTime++) {
449                                                 if(!fClusters[jTime]) continue;
450                                                 fX0 = fClusters[jTime]->GetX() + fdX * (jTime - iTime);
451                                         }
452                                         break;
453                                 }
454                         }       
455                         
456                         // update YZ reference point
457                         // TODO
458                         
459                         // update x reference positions (calibration/alignment aware)
460                         for (Int_t iTime = 0; iTime < AliTRDtrackerV1::GetNTimeBins(); iTime++) {
461                                 if(!fClusters[iTime]) continue;
462                                 fX[iTime] = fClusters[iTime]->GetX() - fX0;
463                         } 
464                         
465                         AliTRDseed::Update();
466                 }
467         if(AliTRDReconstructor::RecoParam()->GetStreamLevel()>=7) AliInfo(Form("iter = %d nclFit [%d] = %d", iter, fPlane, fN2));
468                 
469                 if(IsOK()){
470                         tquality = GetQuality(kZcorr);
471                         if(tquality < quality) break;
472                         else quality = tquality;
473                 }
474                 kroadz *= 2.;
475         } // Loop: iter
476         if (!IsOK()) return kFALSE;
477
478         CookLabels();
479         UpdateUsed();
480         return kTRUE;   
481 }
482
483 //____________________________________________________________________
484 Bool_t  AliTRDseedV1::AttachClusters(AliTRDtrackingChamber *chamber
485                                        ,Bool_t kZcorr)
486 {
487   //
488   // Projective algorithm to attach clusters to seeding tracklets
489   //
490   // Parameters
491   //
492   // Output
493   //
494   // Detailed description
495   // 1. Collapse x coordinate for the full detector plane
496   // 2. truncated mean on y (r-phi) direction
497   // 3. purge clusters
498   // 4. truncated mean on z direction
499   // 5. purge clusters
500   // 6. fit tracklet
501   //    
502
503         if(!AliTRDReconstructor::RecoParam()){
504                 AliError("Seed can not be used without a valid RecoParam.");
505                 return kFALSE;
506         }
507
508         const Int_t kClusterCandidates = 2 * knTimebins;
509         
510         //define roads
511         Double_t kroady = AliTRDReconstructor::RecoParam()->GetRoad1y();
512         Double_t kroadz = fPadLength * 1.5 + 1.;
513         // correction to y for the tilting angle
514         Float_t zcorr = kZcorr ? fTilt * (fZProb - fZref[0]) : 0.;
515
516         // working variables
517         AliTRDcluster *clusters[kClusterCandidates];
518         Double_t cond[4], yexp[knTimebins], zexp[knTimebins],
519                 yres[kClusterCandidates], zres[kClusterCandidates];
520         Int_t ncl, *index = 0x0, tboundary[knTimebins];
521         
522         // Do cluster projection
523         AliTRDchamberTimeBin *layer = 0x0;
524         Int_t nYclusters = 0; Bool_t kEXIT = kFALSE;
525         for (Int_t iTime = 0; iTime < AliTRDtrackerV1::GetNTimeBins(); iTime++) {
526                 if(!(layer = chamber->GetTB(iTime))) continue;
527                 if(!Int_t(*layer)) continue;
528                 
529                 fX[iTime] = layer->GetX() - fX0;
530                 zexp[iTime] = fZref[0] + fZref[1] * fX[iTime];
531                 yexp[iTime] = fYref[0] + fYref[1] * fX[iTime] - zcorr;
532                 
533                 // build condition and process clusters
534                 cond[0] = yexp[iTime] - kroady; cond[1] = yexp[iTime] + kroady;
535                 cond[2] = zexp[iTime] - kroadz; cond[3] = zexp[iTime] + kroadz;
536                 layer->GetClusters(cond, index, ncl);
537                 for(Int_t ic = 0; ic<ncl; ic++){
538                         AliTRDcluster *c = layer->GetCluster(index[ic]);
539                         clusters[nYclusters] = c;
540                         yres[nYclusters++] = c->GetY() - yexp[iTime];
541                         if(nYclusters >= kClusterCandidates) {
542                                 AliWarning(Form("Cluster candidates reached limit %d. Some may be lost.", kClusterCandidates));
543                                 kEXIT = kTRUE;
544                                 break;
545                         }
546                 }
547                 tboundary[iTime] = nYclusters;
548                 if(kEXIT) break;
549         }
550         
551         // Evaluate truncated mean on the y direction
552         Double_t mean, sigma;
553         AliMathBase::EvaluateUni(nYclusters, yres, mean, sigma, Int_t(nYclusters*.8)-2);
554         // purge cluster candidates
555         Int_t nZclusters = 0;
556         for(Int_t ic = 0; ic<nYclusters; ic++){
557                 if(yres[ic] - mean > 4. * sigma){
558                         clusters[ic] = 0x0;
559                         continue;
560                 }
561                 zres[nZclusters++] = clusters[ic]->GetZ() - zexp[clusters[ic]->GetLocalTimeBin()];
562         }
563         
564         // Evaluate truncated mean on the z direction
565         AliMathBase::EvaluateUni(nZclusters, zres, mean, sigma, Int_t(nZclusters*.8)-2);
566         // purge cluster candidates
567         for(Int_t ic = 0; ic<nZclusters; ic++){
568                 if(zres[ic] - mean > 4. * sigma){
569                         clusters[ic] = 0x0;
570                         continue;
571                 }
572         }
573
574         
575         // Select only one cluster/TimeBin
576         Int_t lastCluster = 0;
577         fN2 = 0;
578         for (Int_t iTime = 0; iTime < AliTRDtrackerV1::GetNTimeBins(); iTime++) {
579                 ncl = tboundary[iTime] - lastCluster;
580                 if(!ncl) continue;
581                 Int_t iptr = lastCluster;
582                 if(ncl > 1){
583                         Float_t dold = 9999.;
584                         for(int ic=lastCluster; ic<tboundary[iTime]; ic++){
585                                 if(!clusters[ic]) continue;
586                                 Float_t y = yexp[iTime] - clusters[ic]->GetY();
587                                 Float_t z = zexp[iTime] - clusters[ic]->GetZ();
588                                 Float_t d = y * y + z * z;
589                                 if(d > dold) continue;
590                                 dold = d;
591                                 iptr = ic;
592                         }
593                 }
594                 fIndexes[iTime]  = chamber->GetTB(iTime)->GetGlobalIndex(iptr);
595                 fClusters[iTime] = clusters[iptr];
596                 fY[iTime]        = clusters[iptr]->GetY();
597                 fZ[iTime]        = clusters[iptr]->GetZ();
598                 lastCluster      = tboundary[iTime];
599                 fN2++;
600         }
601         
602         // number of minimum numbers of clusters expected for the tracklet
603         Int_t kClmin = Int_t(AliTRDReconstructor::RecoParam()->GetFindableClusters()*AliTRDtrackerV1::GetNTimeBins());
604   if (fN2 < kClmin){
605                 AliWarning(Form("Not enough clusters to fit the tracklet %d [%d].", fN2, kClmin));
606     fN2 = 0;
607     return kFALSE;
608   }
609
610         // update used clusters
611         fNUsed = 0;
612         for (Int_t iTime = 0; iTime < AliTRDtrackerV1::GetNTimeBins(); iTime++) {
613                 if(!fClusters[iTime]) continue;
614                 if((fClusters[iTime]->IsUsed())) fNUsed++;
615         }
616
617   if (fN2-fNUsed < kClmin){
618                 AliWarning(Form("Too many clusters already in use %d (from %d).", fNUsed, fN2));
619     fN2 = 0;
620     return kFALSE;
621   }
622         
623         return kTRUE;
624 }
625
626 //____________________________________________________________________
627 Bool_t AliTRDseedV1::Fit()
628 {
629   //
630   // Linear fit of the tracklet
631   //
632   // Parameters :
633   //
634   // Output :
635   //  True if successful
636   //
637   // Detailed description
638   // 2. Check if tracklet crosses pad row boundary
639   // 1. Calculate residuals in the y (r-phi) direction
640   // 3. Do a Least Square Fit to the data
641   //
642
643         const Int_t kClmin = 8;
644         const Int_t kNtb = AliTRDtrackerV1::GetNTimeBins();
645         AliTRDtrackerV1::AliTRDLeastSquare fitterY, fitterZ;
646
647         // convertion factor from square to gauss distribution for sigma
648         Double_t convert = 1./TMath::Sqrt(12.);
649
650         // book cluster information
651         Double_t xc[knTimebins+1], yc[knTimebins], zc[knTimebins+1], sy[knTimebins], sz[knTimebins+1];
652         Int_t zRow[knTimebins];
653         AliTRDcluster *c = 0x0;
654         Int_t nc = 0;
655         for (Int_t ic=0; ic<kNtb; ic++) {
656                 zRow[ic] = -1;
657                 xc[ic]  = -1.;
658                 yc[ic]  = 999.;
659                 zc[ic]  = 999.;
660                 sy[ic]  = 0.;
661                 sz[ic]  = 0.;
662                 if(!(c = fClusters[ic])) continue;
663                 if(!c->IsInChamber()) continue;
664                 Float_t w = 1.;
665                 if(c->GetNPads()>4) w = .5;
666                 if(c->GetNPads()>5) w = .2;
667                 zRow[nc] = c->GetPadRow();
668                 xc[nc]   = fX0 - c->GetX();
669                 yc[nc]   = c->GetY();
670                 zc[nc]   = c->GetZ();
671                 sy[ic]   = w; // all clusters have the same sigma
672                 sz[ic]   = fPadLength*convert;
673                 fitterZ.AddPoint(&xc[ic], zc[ic], sz[ic]);
674                 nc++;
675         }
676   // to few clusters
677         if (nc < kClmin) return kFALSE; 
678         
679
680         Int_t zN[2*35];
681   Int_t nz = AliTRDtrackerV1::Freq(nc, zRow, zN, kFALSE);
682         // more than one pad row crossing
683         if(nz>2) return kFALSE; 
684         
685         // estimate reference parameter at average x
686         Double_t y0 = fYref[0];
687         Double_t dydx = fYref[1]; 
688         Double_t dzdx = fZref[1];
689         zc[nc]  = fZref[0];
690
691         // determine z offset of the fit
692         Int_t nchanges = 0, nCross = 0;
693         if(nz==2){ // tracklet is crossing pad row
694                 // Find the break time allowing one chage on pad-rows
695                 // with maximal number of accepted clusters
696                 Int_t padRef = zRow[0];
697                 for (Int_t ic=1; ic<nc; ic++) {
698                         if(zRow[ic] == padRef) continue;
699                         
700                         // debug
701                         if(zRow[ic-1] == zRow[ic]){
702                                 printf("ERROR in pad row change!!!\n");
703                         }
704                 
705                         // evaluate parameters of the crossing point
706                         Float_t sx = (xc[ic-1] - xc[ic])*convert;
707                         xc[nc] = .5 * (xc[ic-1] + xc[ic]);
708                         zc[nc] = .5 * (zc[ic-1] + zc[ic]);
709                         sz[nc] = TMath::Max(dzdx * sx, .01);
710                         dzdx   = zc[ic-1] > zc[ic] ? 1. : -1.;
711                         padRef = zRow[ic];
712                         nCross = ic;
713                         nchanges++;
714                 }
715         }
716
717         // condition on nCross and reset nchanges TODO
718
719         if(nchanges==1){
720                 if(dzdx * fZref[1] < 0.){
721                         AliInfo("tracklet direction does not correspond to the track direction. TODO.");
722                 }
723                 SetBit(2, kTRUE); // mark pad row crossing
724                 fCross[0] = xc[nc]; fCross[2] = zc[nc]; fCross[3] = sz[nc]; 
725                 fitterZ.AddPoint(&xc[nc], zc[nc], sz[nc]);
726                 fitterZ.Eval();
727                 dzdx = fZref[1]; // we don't trust Parameter[1] ??;
728                 zc[nc] = fitterZ.GetFunctionParameter(0); 
729         } else if(nchanges > 1){ // debug
730                 AliInfo("ERROR in n changes!!!");
731                 return kFALSE;
732         }
733
734         
735         // estimate deviation from reference direction
736         dzdx *= fTilt;
737         for (Int_t ic=0; ic<nc; ic++) {
738                 yc[ic] -= y0 + xc[ic]*(dydx + dzdx) + fTilt * (zc[ic] - zc[nc]);
739                 fitterY.AddPoint(&xc[ic], yc[ic], sy[ic]);
740         }
741         fitterY.Eval();
742         fYfit[0] = y0+fitterY.GetFunctionParameter(0);
743         fYfit[1] = dydx+fitterY.GetFunctionParameter(1);
744         if(nchanges) fCross[1] = fYfit[0] + fCross[0] * fYfit[1];
745
746 //      printf("\nnz = %d\n", nz);
747 //      for(int ic=0; ic<35; ic++) printf("%d row[%d]\n", ic, zRow[ic]);        
748 // 
749 //      for(int ic=0; ic<nz; ic++) printf("%d n[%d]\n", ic, zN[ic]);    
750
751         return kTRUE;
752 }
753
754 //___________________________________________________________________
755 void AliTRDseedV1::Draw(Option_t*)
756 {
757 }
758
759 //___________________________________________________________________
760 void AliTRDseedV1::Print(Option_t*) const
761 {
762   //
763   // Printing the seedstatus
764   //
765
766         printf("Seed status :\n");
767         printf("  fTilt      = %f\n", fTilt);
768         printf("  fPadLength = %f\n", fPadLength);
769         printf("  fX0        = %f\n", fX0);
770         for(int ic=0; ic<AliTRDtrackerV1::GetNTimeBins(); ic++) {
771           const Char_t *isUsable = fUsable[ic]?"Yes":"No";
772           printf("  %d X[%f] Y[%f] Z[%f] Indexes[%d] clusters[%p] usable[%s]\n"
773                 , ic
774                 , fX[ic]
775                 , fY[ic]
776                 , fZ[ic]
777                 , fIndexes[ic]
778                 , ((void*) fClusters[ic])
779                 , isUsable);
780         }
781
782         printf("  fYref[0] =%f fYref[1] =%f\n", fYref[0], fYref[1]);
783         printf("  fZref[0] =%f fZref[1] =%f\n", fZref[0], fZref[1]);
784         printf("  fYfit[0] =%f fYfit[1] =%f\n", fYfit[0], fYfit[1]);
785         printf("  fYfitR[0]=%f fYfitR[1]=%f\n", fYfitR[0], fYfitR[1]);
786         printf("  fZfit[0] =%f fZfit[1] =%f\n", fZfit[0], fZfit[1]);
787         printf("  fZfitR[0]=%f fZfitR[1]=%f\n", fZfitR[0], fZfitR[1]);
788         printf("  fSigmaY =%f\n", fSigmaY);
789         printf("  fSigmaY2=%f\n", fSigmaY2);            
790         printf("  fMeanz  =%f\n", fMeanz);
791         printf("  fZProb  =%f\n", fZProb);
792         printf("  fLabels[0]=%d fLabels[1]=%d\n", fLabels[0], fLabels[1]);
793         printf("  fN      =%d\n", fN);
794         printf("  fN2     =%d (>8 isOK)\n",fN2);
795         printf("  fNUsed  =%d\n", fNUsed);
796         printf("  fFreq   =%d\n", fFreq);
797         printf("  fNChange=%d\n",  fNChange);
798         printf("  fMPads  =%f\n", fMPads);
799         
800         printf("  fC      =%f\n", fC);        
801         printf("  fCC     =%f\n",fCC);      
802         printf("  fChi2   =%f\n", fChi2);  
803         printf("  fChi2Z  =%f\n", fChi2Z);
804 }
805