TRD/AliTRDseedV1.cxx

   1 /**************************************************************************
   2  * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
   3  *                                                                        *
   4  * Author: The ALICE Off-line Project.                                    *
   5  * Contributors are mentioned in the code where appropriate.              *
   6  *                                                                        *
   7  * Permission to use, copy, modify and distribute this software and its   *
   8  * documentation strictly for non-commercial purposes is hereby granted   *
   9  * without fee, provided that the above copyright notice appears in all   *
  10  * copies and that both the copyright notice and this permission notice   *
  11  * appear in the supporting documentation. The authors make no claims     *
  12  * about the suitability of this software for any purpose. It is          *
  13  * provided "as is" without express or implied warranty.                  *
  14  **************************************************************************/
  15
  16 /* $Id$ */
  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
  31 #include "AliLog.h"
  32 #include "AliMathBase.h"
  33
  34 #include "AliTRDseedV1.h"
  35 #include "AliTRDcluster.h"
  36 #include "AliTRDcalibDB.h"
  37 #include "AliTRDstackLayer.h"
  38 #include "AliTRDrecoParam.h"
  39
  40 #define SEED_DEBUG
  41
  42 ClassImp(AliTRDseedV1)
  43
  44 //____________________________________________________________________
  45 AliTRDseedV1::AliTRDseedV1(Int_t layer, AliTRDrecoParam *p)
  46   :AliTRDseed()
  47   ,fLayer(layer)
  48   ,fTimeBins(0)
  49   ,fOwner(kFALSE)
  50   ,fRecoParam(p)
  51 {
  52   //
  53   // Constructor
  54   //
  55
  56         //AliInfo("");
  57         AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
  58         fTimeBins = cal->GetNumberOfTimeBins();
  59
  60 }
  61
  62 //____________________________________________________________________
  63 AliTRDseedV1::AliTRDseedV1(const AliTRDseedV1 &ref, Bool_t owner)
  64   :AliTRDseed((AliTRDseed&)ref)
  65   ,fLayer(ref.fLayer)
  66   ,fTimeBins(ref.fTimeBins)
  67   ,fOwner(kFALSE)
  68   ,fRecoParam(ref.fRecoParam)
  69 {
  70   //
  71   // Copy Constructor performing a deep copy
  72   //
  73
  74         //AliInfo("");
  75
  76         if(owner){
  77                 for(int ic=0; ic<fTimeBins; ic++){
  78                         if(!fClusters[ic]) continue;
  79                         fClusters[ic] = new AliTRDcluster(*fClusters[ic]);
  80                 }
  81                 fOwner = kTRUE;
  82         }
  83
  84 }
  85
  86 //____________________________________________________________________
  87 AliTRDseedV1& AliTRDseedV1::operator=(const AliTRDseedV1 &ref)
  88 {
  89   //
  90   // Assignment Operator using the copy function
  91   //
  92
  93         //AliInfo("");
  94         if(this != &ref){
  95                 ref.Copy(*this);
  96         }
  97         return *this;
  98
  99 }
 100
 101 //____________________________________________________________________
 102 AliTRDseedV1::~AliTRDseedV1()
 103 {
 104   //
 105   // Destructor. The RecoParam object belongs to the underlying tracker.
 106   //
 107
 108         //AliInfo(Form("fOwner[%s]", fOwner?"YES":"NO"));
 109
 110         if(fOwner) delete [] fClusters;
 111 }
 112
 113 //____________________________________________________________________
 114 void AliTRDseedV1::Copy(TObject &ref) const
 115 {
 116   //
 117   // Copy function
 118   //
 119
 120         //AliInfo("");
 121         AliTRDseedV1 &target = (AliTRDseedV1 &)ref;
 122
 123         target.fLayer     = fLayer;
 124         target.fTimeBins  = fTimeBins;
 125         target.fRecoParam = fRecoParam;
 126         AliTRDseed::Copy(target);
 127 }
 128
 129 //____________________________________________________________________
 130 Float_t AliTRDseedV1::GetQuality(Bool_t kZcorr) const
 131 {
 132   //
 133   // Returns a quality measurement of the current seed
 134   //
 135
 136         Float_t zcorr = kZcorr ? fTilt * (fZProb - fZref[0]) : 0.;
 137         return .5 * (18.0 - fN2)
 138                 + 10.* TMath::Abs(fYfit[1] - fYref[1])
 139                 + 5.* TMath::Abs(fYfit[0] - fYref[0] + zcorr)
 140                 + 2. * TMath::Abs(fMeanz - fZref[0]) / fPadLength;
 141 }
 142
 143 //____________________________________________________________________
 144 Bool_t  AliTRDseedV1::AttachClustersIter(AliTRDstackLayer *layer
 145                                        , Float_t quality
 146                                        , Bool_t kZcorr
 147                                        , AliTRDcluster *c)
 148 {
 149   //
 150   // Iterative process to register clusters to the seed.
 151   // In iteration 0 we try only one pad-row and if quality not
 152   // sufficient we try 2 pad-rows (about 5% of tracks cross 2 pad-rows)
 153   //
 154
 155         if(!fRecoParam){
 156                 AliError("Seed can not be used without a valid RecoParam.");
 157                 return kFALSE;
 158         }
 159
 160         Float_t  tquality;
 161         Double_t kroady = fRecoParam->GetRoad1y();
 162         Double_t kroadz = fPadLength * .5 + 1.;
 163
 164         // initialize configuration parameters
 165         Float_t zcorr = kZcorr ? fTilt * (fZProb - fZref[0]) : 0.;
 166         Int_t   niter = kZcorr ? 1 : 2;
 167
 168         Double_t yexp, zexp;
 169         Int_t ncl = 0;
 170         // start seed update
 171         for (Int_t iter = 0; iter < niter; iter++) {
 172         //AliInfo(Form("iter = %i", iter));
 173                 ncl = 0;
 174                 for (Int_t iTime = 0; iTime < fTimeBins; iTime++) {
 175                         // define searching configuration
 176                         Double_t dxlayer = layer[iTime].GetX() - fX0;
 177                         if(c){
 178                                 zexp = c->GetZ();
 179                                 //Try 2 pad-rows in second iteration
 180                                 if (iter > 0) {
 181                                         zexp = fZref[0] + fZref[1] * dxlayer - zcorr;
 182                                         if (zexp > c->GetZ()) zexp = c->GetZ() + fPadLength*0.5;
 183                                         if (zexp < c->GetZ()) zexp = c->GetZ() - fPadLength*0.5;
 184                                 }
 185                         } else zexp = fZref[0];
 186                         yexp  = fYref[0] + fYref[1] * dxlayer - zcorr;
 187                         // get  cluster
 188 //                      printf("xexp = %3.3f ,yexp = %3.3f, zexp = %3.3f\n",layer[iTime].GetX(),yexp,zexp);
 189 //                      printf("layer[%i].GetNClusters() = %i\n", iTime, layer[iTime].GetNClusters());
 190                         Int_t    index = layer[iTime].SearchNearestCluster(yexp, zexp, kroady, kroadz);
 191 //                      for(Int_t iclk = 0; iclk < layer[iTime].GetNClusters(); iclk++){
 192 //                              AliTRDcluster *testcl = layer[iTime].GetCluster(iclk);
 193 //                              printf("Cluster %i: x = %3.3f, y = %3.3f, z = %3.3f\n",iclk,testcl->GetX(), testcl->GetY(), testcl->GetZ());
 194 //                      }
 195 //                      printf("Index = %i\n",index);
 196                         if (index < 0) continue;
 197
 198                         // Register cluster
 199                         AliTRDcluster *cl = (AliTRDcluster*) layer[iTime].GetCluster(index);
 200
 201                         //printf("Cluster %i(0x%x): x = %3.3f, y = %3.3f, z = %3.3f\n", index, cl, cl->GetX(), cl->GetY(), cl->GetZ());
 202
 203                         Int_t GlobalIndex = layer[iTime].GetGlobalIndex(index);
 204                         fIndexes[iTime]  = GlobalIndex;
 205                         fClusters[iTime] = cl;
 206                         fX[iTime]        = dxlayer;
 207                         fY[iTime]        = cl->GetY();
 208                         fZ[iTime]        = cl->GetZ();
 209
 210                         // Debugging
 211                         ncl++;
 212                 }
 213
 214 #ifdef SEED_DEBUG
 215 //              Int_t nclusters = 0;
 216 //              Float_t fD[iter] = 0.;
 217 //              for(int ic=0; ic<fTimeBins+1; ic++){
 218 //                      AliTRDcluster *ci = fClusters[ic];
 219 //                      if(!ci) continue;
 220 //                      for(int jc=ic+1; jc<fTimeBins+1; jc++){
 221 //                              AliTRDcluster *cj = fClusters[jc];
 222 //                              if(!cj) continue;
 223 //                              fD[iter] += TMath::Sqrt((ci->GetY()-cj->GetY())*(ci->GetY()-cj->GetY())+
 224 //                              (ci->GetZ()-cj->GetZ())*(ci->GetZ()-cj->GetZ()));
 225 //                              nclusters++;
 226 //                      }
 227 //              }
 228 //              if(nclusters) fD[iter] /= float(nclusters);
 229 #endif
 230
 231                 AliTRDseed::Update();
 232
 233                 if(IsOK()){
 234                         tquality = GetQuality(kZcorr);
 235                         if(tquality < quality) break;
 236                         else quality = tquality;
 237                 }
 238                 kroadz *= 2.;
 239         } // Loop: iter
 240         if (!IsOK()) return kFALSE;
 241
 242         CookLabels();
 243         UpdateUsed();
 244         return kTRUE;
 245 }
 246
 247 //____________________________________________________________________
 248 Bool_t  AliTRDseedV1::AttachClustersProj(AliTRDstackLayer *layer
 249                                        , Float_t /*quality*/
 250                                        , Bool_t kZcorr
 251                                        , AliTRDcluster *c)
 252 {
 253   //
 254   // Projective algorithm to attach clusters to seeding tracklets
 255   //
 256   // Parameters
 257   //
 258   // Output
 259   //
 260   // Detailed description
 261   // 1. Collapse x coordinate for the full detector plane
 262   // 2. truncated mean on y (r-phi) direction
 263   // 3. purge clusters
 264   // 4. truncated mean on z direction
 265   // 5. purge clusters
 266   // 6. fit tracklet
 267   //
 268
 269         if(!fRecoParam){
 270                 AliError("Seed can not be used without a valid RecoParam.");
 271                 return kFALSE;
 272         }
 273
 274         const Int_t knTimeBins = 35;
 275         const Int_t kClusterCandidates = 2 * knTimeBins;
 276
 277         //define roads
 278         Double_t kroady = fRecoParam->GetRoad1y();
 279         Double_t kroadz = fPadLength * 1.5 + 1.;
 280         // correction to y for the tilting angle
 281         Float_t zcorr = kZcorr ? fTilt * (fZProb - fZref[0]) : 0.;
 282
 283         // working variables
 284         AliTRDcluster *clusters[kClusterCandidates];
 285         Double_t cond[4], yexp[knTimeBins], zexp[knTimeBins],
 286                 yres[kClusterCandidates], zres[kClusterCandidates];
 287         Int_t ncl, *index = 0x0, tboundary[knTimeBins];
 288
 289         // Do cluster projection
 290         Int_t nYclusters = 0; Bool_t kEXIT = kFALSE;
 291         for (Int_t iTime = 0; iTime < fTimeBins; iTime++) {
 292                 fX[iTime] = layer[iTime].GetX() - fX0;
 293                 zexp[iTime] = fZref[0] + fZref[1] * fX[iTime];
 294                 yexp[iTime] = fYref[0] + fYref[1] * fX[iTime] - zcorr;
 295
 296                 // build condition and process clusters
 297                 cond[0] = yexp[iTime] - kroady; cond[1] = yexp[iTime] + kroady;
 298                 cond[2] = zexp[iTime] - kroadz; cond[3] = zexp[iTime] + kroadz;
 299                 layer[iTime].GetClusters(cond, index, ncl);
 300                 for(Int_t ic = 0; ic<ncl; ic++){
 301                         c = layer[iTime].GetCluster(index[ic]);
 302                         clusters[nYclusters] = c;
 303                         yres[nYclusters++] = c->GetY() - yexp[iTime];
 304                         if(nYclusters >= kClusterCandidates) {
 305                                 AliWarning(Form("Cluster candidates reached limit %d. Some may be lost.", kClusterCandidates));
 306                                 kEXIT = kTRUE;
 307                                 break;
 308                         }
 309                 }
 310                 tboundary[iTime] = nYclusters;
 311                 if(kEXIT) break;
 312         }
 313
 314         // Evaluate truncated mean on the y direction
 315         Double_t mean, sigma;
 316         AliMathBase::EvaluateUni(nYclusters, yres, mean, sigma, Int_t(nYclusters*.8)-2);
 317         //purge cluster candidates
 318         Int_t nZclusters = 0;
 319         for(Int_t ic = 0; ic<nYclusters; ic++){
 320                 if(yres[ic] - mean > 4. * sigma){
 321                         clusters[ic] = 0x0;
 322                         continue;
 323                 }
 324                 zres[nZclusters++] = clusters[ic]->GetZ() - zexp[clusters[ic]->GetLocalTimeBin()];
 325         }
 326
 327         // Evaluate truncated mean on the z direction
 328         AliMathBase::EvaluateUni(nZclusters, zres, mean, sigma, Int_t(nZclusters*.8)-2);
 329         //purge cluster candidates
 330         for(Int_t ic = 0; ic<nZclusters; ic++){
 331                 if(zres[ic] - mean > 4. * sigma){
 332                         clusters[ic] = 0x0;
 333                         continue;
 334                 }
 335         }
 336
 337
 338         // Select only one cluster/TimeBin
 339         Int_t lastCluster = 0;
 340         fN2 = 0;
 341         for (Int_t iTime = 0; iTime < fTimeBins; iTime++) {
 342                 ncl = tboundary[iTime] - lastCluster;
 343                 if(!ncl) continue;
 344                 if(ncl == 1){
 345                         c = clusters[lastCluster];
 346                 } else if(ncl > 1){
 347                         Float_t dold = 9999.; Int_t iptr = lastCluster;
 348                         for(int ic=lastCluster; ic<tboundary[iTime]; ic++){
 349                                 if(!clusters[ic]) continue;
 350                                 Float_t y = yexp[iTime] - clusters[ic]->GetY();
 351                                 Float_t z = zexp[iTime] - clusters[ic]->GetZ();
 352                                 Float_t d = y * y + z * z;
 353                                 if(d > dold) continue;
 354                                 dold = d;
 355                                 iptr = ic;
 356                         }
 357                         c = clusters[iptr];
 358                 }
 359                 //Int_t GlobalIndex = layer[iTime].GetGlobalIndex(index);
 360                 //fIndexes[iTime]  = GlobalIndex;
 361                 fClusters[iTime] = c;
 362                 fY[iTime]        = c->GetY();
 363                 fZ[iTime]        = c->GetZ();
 364                 lastCluster = tboundary[iTime];
 365                 fN2++;
 366         }
 367
 368         // number of minimum numbers of clusters expected for the tracklet
 369         Int_t kClmin = Int_t(fRecoParam->GetFindableClusters()*fTimeBins);
 370   if (fN2 < kClmin){
 371                 AliWarning(Form("Not enough clusters to fit the tracklet %d [%d].", fN2, kClmin));
 372     fN2 = 0;
 373     return kFALSE;
 374   }
 375         AliTRDseed::Update();
 376
 377 //      // fit tracklet and update clusters
 378 //      if(!FitTracklet()) return kFALSE;
 379 //      UpdateUsed();
 380         return kTRUE;
 381 }
 382
 383 //____________________________________________________________________
 384 Bool_t AliTRDseedV1::FitTracklet()
 385 {
 386   //
 387   // Linear fit of the tracklet
 388   //
 389   // Parameters :
 390   //
 391   // Output :
 392   //  True if successful
 393   //
 394   // Detailed description
 395   // 2. Check if tracklet crosses pad row boundary
 396   // 1. Calculate residuals in the y (r-phi) direction
 397   // 3. Do a Least Square Fit to the data
 398   //
 399
 400         //Float_t  sigmaexp  = 0.05 + TMath::Abs(fYref[1] * 0.25); // Expected r.m.s in y direction
 401   Float_t  ycrosscor = fPadLength * fTilt * 0.5; // Y correction for crossing
 402   Float_t  anglecor = fTilt * fZref[1];  // Correction to the angle
 403
 404         // calculate residuals
 405         const Int_t knTimeBins = 35;
 406         Float_t yres[knTimeBins]; // y (r-phi) residuals
 407         Int_t zint[knTimeBins],   // Histograming of the z coordinate
 408               zout[2*knTimeBins];//
 409
 410         fN = 0;
 411         for (Int_t iTime = 0; iTime < fTimeBins; iTime++) {
 412     if (!fClusters[iTime]) continue;
 413     yres[iTime] = fY[iTime] - fYref[0] - (fYref[1] + anglecor) * fX[iTime];
 414                 zint[fN++] = Int_t(fZ[iTime]);
 415         }
 416
 417         // calculate pad row boundary crosses
 418         Int_t kClmin = Int_t(fRecoParam->GetFindableClusters()*fTimeBins);
 419         Int_t nz = AliMathBase::Freq(fN, zint, zout, kFALSE);
 420   fZProb   = zout[0];
 421   if(nz <= 1) zout[3] = 0;
 422   if(zout[1] + zout[3] < kClmin) {
 423                 AliWarning(Form("Not enough clusters to fit the cross boundary tracklet %d [%d].", zout[1]+zout[3], kClmin));
 424                 return kFALSE;
 425         }
 426   // Z distance bigger than pad - length
 427   if (TMath::Abs(zout[0]-zout[2]) > fPadLength) zout[3]=0;
 428
 429
 430   Double_t sumw   = 0.,
 431                 sumwx  = 0.,
 432                 sumwx2 = 0.,
 433                 sumwy  = 0.,
 434                 sumwxy = 0.,
 435                 sumwz  = 0.,
 436                 sumwxz = 0.;
 437         Int_t npads;
 438   fMPads = 0;
 439         fMeanz = 0.;
 440         for(int iTime=0; iTime<fTimeBins; iTime++){
 441     fUsable[iTime] = kFALSE;
 442     if (!fClusters[iTime]) continue;
 443                 npads = fClusters[iTime]->GetNPads();
 444
 445                 fUsable[iTime] = kTRUE;
 446     fN2++;
 447     fMPads += npads;
 448     Float_t weight = 1.0;
 449     if(npads > 5) weight = 0.2;
 450     else if(npads > 4) weight = 0.5;
 451     sumw   += weight;
 452     sumwx  += fX[iTime] * weight;
 453     sumwx2 += fX[iTime] * fX[iTime] * weight;
 454     sumwy  += weight * yres[iTime];
 455     sumwxy += weight * yres[iTime] * fX[iTime];
 456     sumwz  += weight * fZ[iTime];
 457     sumwxz += weight * fZ[iTime] * fX[iTime];
 458         }
 459   if (fN2 < kClmin){
 460                 AliWarning(Form("Not enough clusters to fit the tracklet %d [%d].", fN2, kClmin));
 461     fN2 = 0;
 462     return kFALSE;
 463   }
 464   fMeanz = sumwz / sumw;
 465         fNChange = 0;
 466
 467         // Tracklet on boundary
 468   Float_t correction = 0;
 469   if (fNChange > 0) {
 470     if (fMeanz < fZProb) correction =  ycrosscor;
 471     if (fMeanz > fZProb) correction = -ycrosscor;
 472   }
 473
 474   Double_t det = sumw * sumwx2 - sumwx * sumwx;
 475   fYfitR[0]    = (sumwx2 * sumwy  - sumwx * sumwxy) / det;
 476   fYfitR[1]    = (sumw   * sumwxy - sumwx * sumwy)  / det;
 477
 478   fSigmaY2 = 0;
 479   for (Int_t i = 0; i < fTimeBins+1; i++) {
 480     if (!fUsable[i]) continue;
 481     Float_t delta = yres[i] - fYfitR[0] - fYfitR[1] * fX[i];
 482     fSigmaY2 += delta*delta;
 483   }
 484   fSigmaY2 = TMath::Sqrt(fSigmaY2 / Float_t(fN2-2));
 485
 486   fZfitR[0]  = (sumwx2 * sumwz  - sumwx * sumwxz) / det;
 487   fZfitR[1]  = (sumw   * sumwxz - sumwx * sumwz)  / det;
 488   fZfit[0]   = (sumwx2 * sumwz  - sumwx * sumwxz) / det;
 489   fZfit[1]   = (sumw   * sumwxz - sumwx * sumwz)  / det;
 490   fYfitR[0] += fYref[0] + correction;
 491   fYfitR[1] += fYref[1];
 492   fYfit[0]   = fYfitR[0];
 493   fYfit[1]   = fYfitR[1];
 494
 495         return kTRUE;
 496 }
 497
 498 //_____________________________________________________________________________
 499 Float_t AliTRDseedV1::FitRiemanTilt(AliTRDseedV1 *cseed, Bool_t terror)
 500 {
 501   //
 502   // Fit the Rieman tilt
 503   //
 504
 505   // Fitting with tilting pads - kz not fixed
 506         AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
 507         Int_t nTimeBins = cal->GetNumberOfTimeBins();
 508   TLinearFitter fitterT2(4,"hyp4");
 509   fitterT2.StoreData(kTRUE);
 510   Float_t xref2 = (cseed[2].fX0 + cseed[3].fX0) * 0.5; // Reference x0 for z
 511
 512   Int_t npointsT = 0;
 513   fitterT2.ClearPoints();
 514
 515   for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
 516 //              printf("\nLayer %d\n", iLayer);
 517 //     cseed[iLayer].Print();
 518                 if (!cseed[iLayer].IsOK()) continue;
 519     Double_t tilt = cseed[iLayer].fTilt;
 520
 521     for (Int_t itime = 0; itime < nTimeBins+1; itime++) {
 522 //                      printf("\ttime %d\n", itime);
 523       if (!cseed[iLayer].fUsable[itime]) continue;
 524       // x relative to the midle chamber
 525       Double_t x = cseed[iLayer].fX[itime] + cseed[iLayer].fX0 - xref2;
 526       Double_t y = cseed[iLayer].fY[itime];
 527       Double_t z = cseed[iLayer].fZ[itime];
 528
 529       //
 530       // Tilted rieman
 531       //
 532       Double_t uvt[6];
 533       Double_t x2 = cseed[iLayer].fX[itime] + cseed[iLayer].fX0;      // Global x
 534       Double_t t  = 1.0 / (x2*x2 + y*y);
 535       uvt[1]  = t;
 536       uvt[0]  = 2.0 * x2   * uvt[1];
 537       uvt[2]  = 2.0 * tilt * uvt[1];
 538       uvt[3]  = 2.0 * tilt *uvt[1] * x;
 539       uvt[4]  = 2.0 * (y + tilt * z) * uvt[1];
 540
 541       Double_t error = 2.0 * uvt[1];
 542       if (terror) {
 543         error *= cseed[iLayer].fSigmaY;
 544       }
 545       else {
 546         error *= 0.2; //Default error
 547       }
 548 //                      printf("\tadd point :\n");
 549 //                      for(int i=0; i<5; i++) printf("%f ", uvt[i]);
 550 //                      printf("\n");
 551       fitterT2.AddPoint(uvt,uvt[4],error);
 552       npointsT++;
 553
 554     }
 555
 556   }
 557   fitterT2.Eval();
 558   Double_t rpolz0 = fitterT2.GetParameter(3);
 559   Double_t rpolz1 = fitterT2.GetParameter(4);
 560
 561   //
 562   // Linear fitter  - not possible to make boundaries
 563   // non accept non possible z and dzdx combination
 564   //
 565   Bool_t acceptablez = kTRUE;
 566   for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
 567     if (cseed[iLayer].IsOK()) {
 568       Double_t zT2 = rpolz0 + rpolz1 * (cseed[iLayer].fX0 - xref2);
 569       if (TMath::Abs(cseed[iLayer].fZProb - zT2) > cseed[iLayer].fPadLength * 0.5 + 1.0) {
 570         acceptablez = kFALSE;
 571       }
 572     }
 573   }
 574   if (!acceptablez) {
 575     Double_t zmf  = cseed[2].fZref[0] + cseed[2].fZref[1] * (xref2 - cseed[2].fX0);
 576     Double_t dzmf = (cseed[2].fZref[1] + cseed[3].fZref[1]) * 0.5;
 577     fitterT2.FixParameter(3,zmf);
 578     fitterT2.FixParameter(4,dzmf);
 579     fitterT2.Eval();
 580     fitterT2.ReleaseParameter(3);
 581     fitterT2.ReleaseParameter(4);
 582     rpolz0 = fitterT2.GetParameter(3);
 583     rpolz1 = fitterT2.GetParameter(4);
 584   }
 585
 586   Double_t chi2TR = fitterT2.GetChisquare() / Float_t(npointsT);
 587   Double_t params[3];
 588   params[0] =  fitterT2.GetParameter(0);
 589   params[1] =  fitterT2.GetParameter(1);
 590   params[2] =  fitterT2.GetParameter(2);
 591   Double_t curvature =  1.0 + params[1] * params[1] - params[2] * params[0];
 592
 593   for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
 594
 595     Double_t  x  = cseed[iLayer].fX0;
 596     Double_t  y  = 0;
 597     Double_t  dy = 0;
 598     Double_t  z  = 0;
 599     Double_t  dz = 0;
 600
 601     // y
 602     Double_t res2 = (x * params[0] + params[1]);
 603     res2 *= res2;
 604     res2  = 1.0 - params[2]*params[0] + params[1]*params[1] - res2;
 605     if (res2 >= 0) {
 606       res2 = TMath::Sqrt(res2);
 607       y    = (1.0 - res2) / params[0];
 608     }
 609
 610     //dy
 611     Double_t x0 = -params[1] / params[0];
 612     if (-params[2]*params[0] + params[1]*params[1] + 1 > 0) {
 613       Double_t rm1 = params[0] / TMath::Sqrt(-params[2]*params[0] + params[1]*params[1] + 1);
 614       if (1.0/(rm1*rm1) - (x-x0) * (x-x0) > 0.0) {
 615         Double_t res = (x - x0) / TMath::Sqrt(1.0 / (rm1*rm1) - (x-x0)*(x-x0));
 616         if (params[0] < 0) res *= -1.0;
 617         dy = res;
 618       }
 619     }
 620     z  = rpolz0 + rpolz1 * (x - xref2);
 621     dz = rpolz1;
 622     cseed[iLayer].fYref[0] = y;
 623     cseed[iLayer].fYref[1] = dy;
 624     cseed[iLayer].fZref[0] = z;
 625     cseed[iLayer].fZref[1] = dz;
 626     cseed[iLayer].fC       = curvature;
 627
 628   }
 629
 630   return chi2TR;
 631
 632 }
 633
 634 //___________________________________________________________________
 635 void AliTRDseedV1::Print()
 636 {
 637   //
 638   // Printing the seedstatus
 639   //
 640
 641         AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
 642         Int_t nTimeBins = cal->GetNumberOfTimeBins();
 643
 644         printf("Seed status :\n");
 645         printf("  fTilt      = %f\n", fTilt);
 646         printf("  fPadLength = %f\n", fPadLength);
 647         printf("  fX0        = %f\n", fX0);
 648         for(int ic=0; ic<nTimeBins; ic++) {
 649           const Char_t *isUsable = fUsable[ic]?"Yes":"No";
 650           printf("  %d X[%f] Y[%f] Z[%f] Indexes[%d] clusters[%#x] usable[%s]\n"
 651                 , ic
 652                 , fX[ic]
 653                 , fY[ic]
 654                 , fZ[ic]
 655                 , fIndexes[ic]
 656                 , ((Int_t) fClusters[ic])
 657                 , isUsable);
 658         }
 659
 660         printf("  fYref[0] =%f fYref[1] =%f\n", fYref[0], fYref[1]);
 661         printf("  fZref[0] =%f fZref[1] =%f\n", fZref[0], fZref[1]);
 662         printf("  fYfit[0] =%f fYfit[1] =%f\n", fYfit[0], fYfit[1]);
 663         printf("  fYfitR[0]=%f fYfitR[1]=%f\n", fYfitR[0], fYfitR[1]);
 664         printf("  fZfit[0] =%f fZfit[1] =%f\n", fZfit[0], fZfit[1]);
 665         printf("  fZfitR[0]=%f fZfitR[1]=%f\n", fZfitR[0], fZfitR[1]);
 666         printf("  fSigmaY =%f\n", fSigmaY);
 667         printf("  fSigmaY2=%f\n", fSigmaY2);
 668         printf("  fMeanz  =%f\n", fMeanz);
 669         printf("  fZProb  =%f\n", fZProb);
 670         printf("  fLabels[0]=%d fLabels[1]=%d\n", fLabels[0], fLabels[1]);
 671         printf("  fN      =%d\n", fN);
 672         printf("  fN2     =%d (>8 isOK)\n",fN2);
 673         printf("  fNUsed  =%d\n", fNUsed);
 674         printf("  fFreq   =%d\n", fFreq);
 675         printf("  fNChange=%d\n",  fNChange);
 676         printf("  fMPads  =%f\n", fMPads);
 677
 678         printf("  fC      =%f\n", fC);
 679         printf("  fCC     =%f\n",fCC);
 680         printf("  fChi2   =%f\n", fChi2);
 681         printf("  fChi2Z  =%f\n", fChi2Z);
 682
 683 }