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 "AliTRDtrack.h"
  37 #include "AliTRDcalibDB.h"
  38 #include "AliTRDstackLayer.h"
  39 #include "AliTRDrecoParam.h"
  40 #include "AliTRDgeometry.h"
  41 #include "Cal/AliTRDCalPID.h"
  42
  43 #define SEED_DEBUG
  44
  45 ClassImp(AliTRDseedV1)
  46
  47 //____________________________________________________________________
  48 AliTRDseedV1::AliTRDseedV1(Int_t layer, AliTRDrecoParam *p)
  49   :AliTRDseed()
  50   ,fPlane(layer)
  51   ,fOwner(kFALSE)
  52   ,fMom(0.)
  53   ,fSnp(0.)
  54   ,fTgl(0.)
  55   ,fdX(0.)
  56   ,fRecoParam(p)
  57 {
  58   //
  59   // Constructor
  60   //
  61         for(int islice=0; islice < knSlices; islice++) fdEdx[islice] = 0.;
  62         for(int ispec=0; ispec<AliPID::kSPECIES; ispec++) fProb[ispec]  = -1.;
  63 }
  64
  65 //____________________________________________________________________
  66 AliTRDseedV1::AliTRDseedV1(const AliTRDseedV1 &ref)
  67   :AliTRDseed((AliTRDseed&)ref)
  68   ,fPlane(ref.fPlane)
  69   ,fOwner(kFALSE)
  70   ,fMom(ref.fMom)
  71   ,fSnp(ref.fSnp)
  72   ,fTgl(ref.fTgl)
  73   ,fdX(ref.fdX)
  74   ,fRecoParam(ref.fRecoParam)
  75 {
  76   //
  77   // Copy Constructor performing a deep copy
  78   //
  79
  80         //AliInfo("");
  81         if(ref.fOwner) SetOwner();
  82         for(int islice=0; islice < knSlices; islice++) fdEdx[islice] = ref.fdEdx[islice];
  83         for(int ispec=0; ispec<AliPID::kSPECIES; ispec++) fProb[ispec] = ref.fProb[ispec];
  84 }
  85
  86
  87 //____________________________________________________________________
  88 AliTRDseedV1& AliTRDseedV1::operator=(const AliTRDseedV1 &ref)
  89 {
  90   //
  91   // Assignment Operator using the copy function
  92   //
  93
  94         //AliInfo("");
  95         if(this != &ref){
  96                 ref.Copy(*this);
  97         }
  98         return *this;
  99
 100 }
 101
 102 //____________________________________________________________________
 103 AliTRDseedV1::~AliTRDseedV1()
 104 {
 105   //
 106   // Destructor. The RecoParam object belongs to the underlying tracker.
 107   //
 108
 109         //AliInfo(Form("fOwner[%s]", fOwner?"YES":"NO"));
 110
 111         if(fOwner)
 112                 for(int itb=0; itb<knTimebins; itb++){
 113                         if(!fClusters[itb]) continue;
 114                         //AliInfo(Form("deleting c %p @ %d", fClusters[itb], itb));
 115                         delete fClusters[itb];
 116                         fClusters[itb] = 0x0;
 117                 }
 118 }
 119
 120 //____________________________________________________________________
 121 void AliTRDseedV1::Copy(TObject &ref) const
 122 {
 123   //
 124   // Copy function
 125   //
 126
 127         //AliInfo("");
 128         AliTRDseedV1 &target = (AliTRDseedV1 &)ref;
 129
 130         target.fPlane         = fPlane;
 131         target.fMom           = fMom;
 132         target.fSnp           = fSnp;
 133         target.fTgl           = fTgl;
 134         target.fdX            = fdX;
 135         target.fRecoParam     = fRecoParam;
 136
 137         for(int islice=0; islice < knSlices; islice++) target.fdEdx[islice] = fdEdx[islice];
 138         for(int ispec=0; ispec<AliPID::kSPECIES; ispec++) target.fProb[ispec] = fProb[ispec];
 139
 140         AliTRDseed::Copy(target);
 141 }
 142
 143
 144 //____________________________________________________________
 145 void AliTRDseedV1::Init(AliTRDtrack *track)
 146 {
 147 // Initialize this tracklet using the track information
 148 //
 149 // Parameters:
 150 //   track - the TRD track used to initialize the tracklet
 151 //
 152 // Detailed description
 153 // The function sets the starting point and direction of the
 154 // tracklet according to the information from the TRD track.
 155 //
 156 // Caution
 157 // The TRD track has to be propagated to the beginning of the
 158 // chamber where the tracklet will be constructed
 159 //
 160
 161         Double_t y, z;
 162         track->GetProlongation(fX0, y, z);
 163         fYref[0] = y;
 164         fYref[1] = track->GetSnp()/(1. - track->GetSnp()*track->GetSnp());
 165         fZref[0] = z;
 166         fZref[1] = track->GetTgl();
 167
 168         //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());
 169 }
 170
 171
 172 //____________________________________________________________________
 173 void AliTRDseedV1::CookdEdx(Int_t nslices)
 174 {
 175 // Calculates average dE/dx for all slices and store them in the internal array fdEdx.
 176 //
 177 // Parameters:
 178 //  nslices : number of slices for which dE/dx should be calculated
 179 // Output:
 180 //  store results in the internal array fdEdx. This can be accessed with the method
 181 //  AliTRDseedV1::GetdEdx()
 182 //
 183 // Detailed description
 184 // Calculates average dE/dx for all slices. Depending on the PID methode
 185 // the number of slices can be 3 (LQ) or 8(NN).
 186 // The calculation of dQ/dl are done using the tracklet fit results (see AliTRDseedV1::GetdQdl(Int_t)) i.e.
 187 //
 188 // dQ/dl = qc/(dx * sqrt(1 + dy/dx^2 + dz/dx^2))
 189 //
 190 // The following effects are included in the calculation:
 191 // 1. calibration values for t0 and vdrift (using x coordinate to calculate slice)
 192 // 2. cluster sharing (optional see AliTRDrecoParam::SetClusterSharing())
 193 // 3. cluster size
 194 //
 195
 196         Int_t nclusters[knSlices];
 197         for(int i=0; i<knSlices; i++){
 198                 fdEdx[i]     = 0.;
 199                 nclusters[i] = 0;
 200         }
 201         Float_t clength = (/*.5 * */AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
 202
 203         AliTRDcluster *cluster = 0x0;
 204         for(int ic=0; ic<fgTimeBins; ic++){
 205                 if(!(cluster = fClusters[ic])) continue;
 206                 Float_t x = cluster->GetX();
 207
 208                 // Filter clusters for dE/dx calculation
 209
 210                 // 1.consider calibration effects for slice determination
 211                 Int_t slice;
 212                 if(cluster->IsInChamber()) slice = Int_t(TMath::Abs(fX0 - x) * nslices / clength);
 213                 else slice = x < fX0 ? 0 : nslices-1;
 214
 215                 // 2. take sharing into account
 216                 Float_t w = cluster->IsShared() ? .5 : 1.;
 217
 218                 // 3. take into account large clusters TODO
 219                 //w *= c->GetNPads() > 3 ? .8 : 1.;
 220
 221                 //CHECK !!!
 222                 fdEdx[slice]   += w * GetdQdl(ic); //fdQdl[ic];
 223                 nclusters[slice]++;
 224         } // End of loop over clusters
 225
 226         // calculate mean charge per slice
 227         for(int is=0; is<nslices; is++) if(nclusters[is]) fdEdx[is] /= nclusters[is];
 228 }
 229
 230 //____________________________________________________________________
 231 Float_t AliTRDseedV1::GetdQdl(Int_t ic) const
 232 {
 233         return fClusters[ic] ? TMath::Abs(fClusters[ic]->GetQ()) /fdX / TMath::Sqrt(1. + fYfit[1]*fYfit[1] + fZfit[1]*fZfit[1]) : 0.;
 234 }
 235
 236 //____________________________________________________________________
 237 Double_t* AliTRDseedV1::GetProbability()
 238 {
 239 // Fill probability array for tracklet from the DB.
 240 //
 241 // Parameters
 242 //
 243 // Output
 244 //   returns pointer to the probability array and 0x0 if missing DB access
 245 //
 246 // Detailed description
 247
 248
 249         // retrive calibration db
 250   AliTRDcalibDB *calibration = AliTRDcalibDB::Instance();
 251   if (!calibration) {
 252     AliError("No access to calibration data");
 253     return 0x0;
 254   }
 255
 256   // Retrieve the CDB container class with the parametric detector response
 257   const AliTRDCalPID *pd = calibration->GetPIDObject(fRecoParam->GetPIDMethod());
 258   if (!pd) {
 259     AliError("No access to AliTRDCalPID object");
 260     return 0x0;
 261   }
 262
 263         // calculate tracklet length TO DO
 264   Float_t length = (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
 265   /// TMath::Sqrt((1.0 - fSnp[iPlane]*fSnp[iPlane]) / (1.0 + fTgl[iPlane]*fTgl[iPlane]));
 266
 267   //calculate dE/dx
 268   CookdEdx(fRecoParam->GetNdEdxSlices());
 269
 270   // Sets the a priori probabilities
 271   for(int ispec=0; ispec<AliPID::kSPECIES; ispec++) {
 272     fProb[ispec] = pd->GetProbability(ispec, fMom, &fdEdx[0], length, fPlane);
 273   }
 274
 275         return &fProb[0];
 276 }
 277
 278 //____________________________________________________________________
 279 Float_t AliTRDseedV1::GetQuality(Bool_t kZcorr) const
 280 {
 281   //
 282   // Returns a quality measurement of the current seed
 283   //
 284
 285         Float_t zcorr = kZcorr ? fTilt * (fZProb - fZref[0]) : 0.;
 286         return .5 * (18.0 - fN2)
 287                 + 10.* TMath::Abs(fYfit[1] - fYref[1])
 288                 + 5.* TMath::Abs(fYfit[0] - fYref[0] + zcorr)
 289                 + 2. * TMath::Abs(fMeanz - fZref[0]) / fPadLength;
 290 }
 291
 292 //____________________________________________________________________
 293 void AliTRDseedV1::GetCovAt(Double_t /*x*/, Double_t *cov) const
 294 {
 295 // Computes covariance in the y-z plane at radial point x
 296
 297         const Float_t k0= .2; // to be checked in FindClusters
 298         Double_t sy20   = k0*TMath::Tan(fYfit[1]); sy20 *= sy20;
 299
 300         Double_t sy2    = fSigmaY2*fSigmaY2 + sy20;
 301         Double_t sz2    = fPadLength/12.;
 302
 303         //printf("Yfit[1] %f sy20 %f SigmaY2 %f\n", fYfit[1], sy20, fSigmaY2);
 304
 305         cov[0] = sy2;
 306         cov[1] = fTilt*(sy2-sz2);
 307         cov[2] = sz2;
 308 }
 309
 310
 311 //____________________________________________________________________
 312 void AliTRDseedV1::SetOwner(Bool_t own)
 313 {
 314         //AliInfo(Form("own [%s] fOwner[%s]", own?"YES":"NO", fOwner?"YES":"NO"));
 315
 316         if(own){
 317                 for(int ic=0; ic<knTimebins; ic++){
 318                         if(!fClusters[ic]) continue;
 319                         fClusters[ic] = new AliTRDcluster(*fClusters[ic]);
 320                 }
 321                 fOwner = kTRUE;
 322         } else {
 323                 if(fOwner){
 324                         for(int ic=0; ic<knTimebins; ic++){
 325                                 if(!fClusters[ic]) continue;
 326                                 delete fClusters[ic];
 327                                 //fClusters[ic] = tracker->GetClusters(index) TODO
 328                         }
 329                 }
 330                 fOwner = kFALSE;
 331         }
 332 }
 333
 334 //____________________________________________________________________
 335 Bool_t  AliTRDseedV1::AttachClustersIter(AliTRDstackLayer *layer
 336                                        , Float_t quality
 337                                        , Bool_t kZcorr
 338                                        , AliTRDcluster *c)
 339 {
 340   //
 341   // Iterative process to register clusters to the seed.
 342   // In iteration 0 we try only one pad-row and if quality not
 343   // sufficient we try 2 pad-rows (about 5% of tracks cross 2 pad-rows)
 344   //
 345
 346         if(!fRecoParam){
 347                 AliError("Seed can not be used without a valid RecoParam.");
 348                 return kFALSE;
 349         }
 350
 351         //AliInfo(Form("TimeBins = %d TimeBinsRange = %d", fgTimeBins, fTimeBinsRange));
 352
 353         Float_t  tquality;
 354         Double_t kroady = fRecoParam->GetRoad1y();
 355         Double_t kroadz = fPadLength * .5 + 1.;
 356
 357         // initialize configuration parameters
 358         Float_t zcorr = kZcorr ? fTilt * (fZProb - fZref[0]) : 0.;
 359         Int_t   niter = kZcorr ? 1 : 2;
 360
 361         Double_t yexp, zexp;
 362         Int_t ncl = 0;
 363         // start seed update
 364         for (Int_t iter = 0; iter < niter; iter++) {
 365         //AliInfo(Form("iter = %i", iter));
 366                 ncl = 0;
 367                 for (Int_t iTime = 0; iTime < fgTimeBins; iTime++) {
 368                         // define searching configuration
 369                         Double_t dxlayer = layer[iTime].GetX() - fX0;
 370                         if(c){
 371                                 zexp = c->GetZ();
 372                                 //Try 2 pad-rows in second iteration
 373                                 if (iter > 0) {
 374                                         zexp = fZref[0] + fZref[1] * dxlayer - zcorr;
 375                                         if (zexp > c->GetZ()) zexp = c->GetZ() + fPadLength*0.5;
 376                                         if (zexp < c->GetZ()) zexp = c->GetZ() - fPadLength*0.5;
 377                                 }
 378                         } else zexp = fZref[0];
 379                         yexp  = fYref[0] + fYref[1] * dxlayer - zcorr;
 380
 381                         // Get and register cluster
 382                         Int_t    index = layer[iTime].SearchNearestCluster(yexp, zexp, kroady, kroadz);
 383                         if (index < 0) continue;
 384                         AliTRDcluster *cl = (AliTRDcluster*) layer[iTime].GetCluster(index);
 385
 386                         Int_t globalIndex = layer[iTime].GetGlobalIndex(index);
 387                         fIndexes[iTime]  = globalIndex;
 388                         fClusters[iTime] = cl;
 389                         fY[iTime]        = cl->GetY();
 390                         fZ[iTime]        = cl->GetZ();
 391                         ncl++;
 392                 }
 393
 394                 if(ncl){
 395                         // calculate length of the time bin (calibration aware)
 396                         Int_t irp = 0; Float_t x[2]; Int_t tb[2];
 397                         for (Int_t iTime = 0; iTime < fgTimeBins; iTime++) {
 398                                 if(!fClusters[iTime]) continue;
 399                                 x[irp]  = fClusters[iTime]->GetX();
 400                                 tb[irp] = iTime;
 401                                 irp++;
 402                                 if(irp==2) break;
 403                         }
 404                         fdX = (x[1] - x[0]) / (tb[0] - tb[1]);
 405
 406                         // update X0 from the clusters (calibration/alignment aware)
 407                         for (Int_t iTime = 0; iTime < fgTimeBins; iTime++) {
 408                                 if(!layer[iTime].IsT0()) continue;
 409                                 if(fClusters[iTime]){
 410                                         fX0 = fClusters[iTime]->GetX();
 411                                         break;
 412                                 } else { // we have to infere the position of the anode wire from the other clusters
 413                                         for (Int_t jTime = iTime+1; jTime < fgTimeBins; jTime++) {
 414                                                 if(!fClusters[jTime]) continue;
 415                                                 fX0 = fClusters[jTime]->GetX() + fdX * (jTime - iTime);
 416                                         }
 417                                         break;
 418                                 }
 419                         }
 420
 421                         // update YZ reference point
 422                         // TODO
 423
 424                         // update x reference positions (calibration/alignment aware)
 425                         for (Int_t iTime = 0; iTime < fgTimeBins; iTime++) {
 426                                 if(!fClusters[iTime]) continue;
 427                                 fX[iTime] = fClusters[iTime]->GetX() - fX0;
 428                         }
 429
 430                         AliTRDseed::Update();
 431                 }
 432
 433                 if(IsOK()){
 434                         tquality = GetQuality(kZcorr);
 435                         if(tquality < quality) break;
 436                         else quality = tquality;
 437                 }
 438                 kroadz *= 2.;
 439         } // Loop: iter
 440         if (!IsOK()) return kFALSE;
 441
 442         CookLabels();
 443         UpdateUsed();
 444         return kTRUE;
 445 }
 446
 447 //____________________________________________________________________
 448 Bool_t  AliTRDseedV1::AttachClusters(AliTRDstackLayer *layer
 449                                        ,Bool_t kZcorr)
 450 {
 451   //
 452   // Projective algorithm to attach clusters to seeding tracklets
 453   //
 454   // Parameters
 455   //
 456   // Output
 457   //
 458   // Detailed description
 459   // 1. Collapse x coordinate for the full detector plane
 460   // 2. truncated mean on y (r-phi) direction
 461   // 3. purge clusters
 462   // 4. truncated mean on z direction
 463   // 5. purge clusters
 464   // 6. fit tracklet
 465   //
 466
 467         if(!fRecoParam){
 468                 AliError("Seed can not be used without a valid RecoParam.");
 469                 return kFALSE;
 470         }
 471
 472         const Int_t kClusterCandidates = 2 * knTimebins;
 473
 474         //define roads
 475         Double_t kroady = fRecoParam->GetRoad1y();
 476         Double_t kroadz = fPadLength * 1.5 + 1.;
 477         // correction to y for the tilting angle
 478         Float_t zcorr = kZcorr ? fTilt * (fZProb - fZref[0]) : 0.;
 479
 480         // working variables
 481         AliTRDcluster *clusters[kClusterCandidates];
 482         Double_t cond[4], yexp[knTimebins], zexp[knTimebins],
 483                 yres[kClusterCandidates], zres[kClusterCandidates];
 484         Int_t ncl, *index = 0x0, tboundary[knTimebins];
 485
 486         // Do cluster projection
 487         Int_t nYclusters = 0; Bool_t kEXIT = kFALSE;
 488         for (Int_t iTime = 0; iTime < fgTimeBins; iTime++) {
 489                 fX[iTime] = layer[iTime].GetX() - fX0;
 490                 zexp[iTime] = fZref[0] + fZref[1] * fX[iTime];
 491                 yexp[iTime] = fYref[0] + fYref[1] * fX[iTime] - zcorr;
 492
 493                 // build condition and process clusters
 494                 cond[0] = yexp[iTime] - kroady; cond[1] = yexp[iTime] + kroady;
 495                 cond[2] = zexp[iTime] - kroadz; cond[3] = zexp[iTime] + kroadz;
 496                 layer[iTime].GetClusters(cond, index, ncl);
 497                 for(Int_t ic = 0; ic<ncl; ic++){
 498                         AliTRDcluster *c = layer[iTime].GetCluster(index[ic]);
 499                         clusters[nYclusters] = c;
 500                         yres[nYclusters++] = c->GetY() - yexp[iTime];
 501                         if(nYclusters >= kClusterCandidates) {
 502                                 AliWarning(Form("Cluster candidates reached limit %d. Some may be lost.", kClusterCandidates));
 503                                 kEXIT = kTRUE;
 504                                 break;
 505                         }
 506                 }
 507                 tboundary[iTime] = nYclusters;
 508                 if(kEXIT) break;
 509         }
 510
 511         // Evaluate truncated mean on the y direction
 512         Double_t mean, sigma;
 513         AliMathBase::EvaluateUni(nYclusters, yres, mean, sigma, Int_t(nYclusters*.8)-2);
 514         //purge cluster candidates
 515         Int_t nZclusters = 0;
 516         for(Int_t ic = 0; ic<nYclusters; ic++){
 517                 if(yres[ic] - mean > 4. * sigma){
 518                         clusters[ic] = 0x0;
 519                         continue;
 520                 }
 521                 zres[nZclusters++] = clusters[ic]->GetZ() - zexp[clusters[ic]->GetLocalTimeBin()];
 522         }
 523
 524         // Evaluate truncated mean on the z direction
 525         AliMathBase::EvaluateUni(nZclusters, zres, mean, sigma, Int_t(nZclusters*.8)-2);
 526         //purge cluster candidates
 527         for(Int_t ic = 0; ic<nZclusters; ic++){
 528                 if(zres[ic] - mean > 4. * sigma){
 529                         clusters[ic] = 0x0;
 530                         continue;
 531                 }
 532         }
 533
 534
 535         // Select only one cluster/TimeBin
 536         Int_t lastCluster = 0;
 537         fN2 = 0;
 538         for (Int_t iTime = 0; iTime < fgTimeBins; iTime++) {
 539                 ncl = tboundary[iTime] - lastCluster;
 540                 if(!ncl) continue;
 541                 AliTRDcluster *c = 0x0;
 542                 if(ncl == 1){
 543                         c = clusters[lastCluster];
 544                 } else if(ncl > 1){
 545                         Float_t dold = 9999.; Int_t iptr = lastCluster;
 546                         for(int ic=lastCluster; ic<tboundary[iTime]; ic++){
 547                                 if(!clusters[ic]) continue;
 548                                 Float_t y = yexp[iTime] - clusters[ic]->GetY();
 549                                 Float_t z = zexp[iTime] - clusters[ic]->GetZ();
 550                                 Float_t d = y * y + z * z;
 551                                 if(d > dold) continue;
 552                                 dold = d;
 553                                 iptr = ic;
 554                         }
 555                         c = clusters[iptr];
 556                 }
 557                 //Int_t GlobalIndex = layer[iTime].GetGlobalIndex(index);
 558                 //fIndexes[iTime]  = GlobalIndex;
 559                 fClusters[iTime] = c;
 560                 fY[iTime]        = c->GetY();
 561                 fZ[iTime]        = c->GetZ();
 562                 lastCluster      = tboundary[iTime];
 563                 fN2++;
 564         }
 565
 566         // number of minimum numbers of clusters expected for the tracklet
 567         Int_t kClmin = Int_t(fRecoParam->GetFindableClusters()*fgTimeBins);
 568   if (fN2 < kClmin){
 569                 AliWarning(Form("Not enough clusters to fit the tracklet %d [%d].", fN2, kClmin));
 570     fN2 = 0;
 571     return kFALSE;
 572   }
 573
 574         // update used clusters
 575         fNUsed = 0;
 576         for (Int_t iTime = 0; iTime < fgTimeBins; iTime++) {
 577                 if(!fClusters[iTime]) continue;
 578                 if((fClusters[iTime]->IsUsed())) fNUsed++;
 579         }
 580
 581   if (fN2-fNUsed < kClmin){
 582                 AliWarning(Form("Too many clusters already in use %d (from %d).", fNUsed, fN2));
 583     fN2 = 0;
 584     return kFALSE;
 585   }
 586
 587         return kTRUE;
 588 }
 589
 590 //____________________________________________________________________
 591 Bool_t AliTRDseedV1::Fit()
 592 {
 593   //
 594   // Linear fit of the tracklet
 595   //
 596   // Parameters :
 597   //
 598   // Output :
 599   //  True if successful
 600   //
 601   // Detailed description
 602   // 2. Check if tracklet crosses pad row boundary
 603   // 1. Calculate residuals in the y (r-phi) direction
 604   // 3. Do a Least Square Fit to the data
 605   //
 606
 607         //Float_t  sigmaexp  = 0.05 + TMath::Abs(fYref[1] * 0.25); // Expected r.m.s in y direction
 608   Float_t  ycrosscor = fPadLength * fTilt * 0.5; // Y correction for crossing
 609   Float_t  anglecor = fTilt * fZref[1];  // Correction to the angle
 610
 611         // calculate residuals
 612         Float_t yres[knTimebins]; // y (r-phi) residuals
 613         Int_t zint[knTimebins],   // Histograming of the z coordinate
 614               zout[2*knTimebins];//
 615
 616         fN = 0;
 617         for (Int_t iTime = 0; iTime < fgTimeBins; iTime++) {
 618     if (!fClusters[iTime]) continue;
 619     if (!fClusters[iTime]->IsInChamber()) continue;
 620     yres[iTime] = fY[iTime] - fYref[0] - (fYref[1] + anglecor) * fX[iTime] + fTilt * (fZ[iTime] - fZref[0]);
 621                 zint[fN] = Int_t(fZ[iTime]);
 622                 fN++;
 623         }
 624
 625         // calculate pad row boundary crosses
 626         Int_t kClmin = Int_t(fRecoParam->GetFindableClusters()*fgTimeBins);
 627         Int_t nz = AliMathBase::Freq(fN, zint, zout, kFALSE);
 628   fZProb   = zout[0];
 629   if(nz <= 1) zout[3] = 0;
 630   if(zout[1] + zout[3] < kClmin) {
 631                 AliWarning(Form("Not enough clusters to fit the cross boundary tracklet %d [%d].", zout[1]+zout[3], kClmin));
 632                 return kFALSE;
 633         }
 634   // Z distance bigger than pad - length
 635   if (TMath::Abs(zout[0]-zout[2]) > fPadLength) zout[3]=0;
 636
 637
 638   Double_t sumw   = 0.,
 639                 sumwx  = 0.,
 640                 sumwx2 = 0.,
 641                 sumwy  = 0.,
 642                 sumwxy = 0.,
 643                 sumwz  = 0.,
 644                 sumwxz = 0.;
 645         Int_t npads;
 646   fMPads = 0;
 647         fMeanz = 0.;
 648         // we will use only the clusters which are in the detector range
 649         for(int iTime=0; iTime<fgTimeBins; iTime++){
 650     fUsable[iTime] = kFALSE;
 651     if (!fClusters[iTime]) continue;
 652                 npads = fClusters[iTime]->GetNPads();
 653
 654                 fUsable[iTime] = kTRUE;
 655     fN2++;
 656     fMPads += npads;
 657     Float_t weight = 1.0;
 658     if(npads > 5) weight = 0.2;
 659     else if(npads > 4) weight = 0.5;
 660     sumw   += weight;
 661     sumwx  += fX[iTime] * weight;
 662     sumwx2 += fX[iTime] * fX[iTime] * weight;
 663     sumwy  += weight * yres[iTime];
 664     sumwxy += weight * yres[iTime] * fX[iTime];
 665     sumwz  += weight * fZ[iTime];
 666     sumwxz += weight * fZ[iTime] * fX[iTime];
 667         }
 668   if (fN2 < kClmin){
 669                 AliWarning(Form("Not enough clusters to fit the tracklet %d [%d].", fN2, kClmin));
 670     fN2 = 0;
 671     return kFALSE;
 672   }
 673   fMeanz = sumwz / sumw;
 674         fNChange = 0;
 675
 676         // Tracklet on boundary
 677   Float_t correction = 0;
 678   if (fNChange > 0) {
 679     if (fMeanz < fZProb) correction =  ycrosscor;
 680     if (fMeanz > fZProb) correction = -ycrosscor;
 681   }
 682
 683   Double_t det = sumw * sumwx2 - sumwx * sumwx;
 684   fYfitR[0]    = (sumwx2 * sumwy  - sumwx * sumwxy) / det;
 685   fYfitR[1]    = (sumw   * sumwxy - sumwx * sumwy)  / det;
 686
 687   fSigmaY2 = 0;
 688   for (Int_t i = 0; i < fgTimeBins+1; i++) {
 689     if (!fUsable[i]) continue;
 690     Float_t delta = yres[i] - fYfitR[0] - fYfitR[1] * fX[i];
 691     fSigmaY2 += delta*delta;
 692   }
 693   fSigmaY2 = TMath::Sqrt(fSigmaY2 / Float_t(fN2-2));
 694
 695   fZfitR[0]  = (sumwx2 * sumwz  - sumwx * sumwxz) / det;
 696   fZfitR[1]  = (sumw   * sumwxz - sumwx * sumwz)  / det;
 697   fZfit[0]   = (sumwx2 * sumwz  - sumwx * sumwxz) / det;
 698   fZfit[1]   = (sumw   * sumwxz - sumwx * sumwz)  / det;
 699   fYfitR[0] += fYref[0] + correction;
 700   fYfitR[1] += fYref[1];
 701   fYfit[0]   = fYfitR[0];
 702   fYfit[1]   = fYfitR[1];
 703
 704         return kTRUE;
 705 }
 706
 707 //_____________________________________________________________________________
 708 Float_t AliTRDseedV1::FitRiemanTilt(AliTRDseedV1 *cseed, Bool_t terror)
 709 {
 710   //
 711   // Fit the Rieman tilt
 712   //
 713
 714   // Fitting with tilting pads - kz not fixed
 715         AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
 716         Int_t nTimeBins = cal->GetNumberOfTimeBins();
 717   TLinearFitter fitterT2(4,"hyp4");
 718   fitterT2.StoreData(kTRUE);
 719   Float_t xref2 = (cseed[2].fX0 + cseed[3].fX0) * 0.5; // Reference x0 for z
 720
 721   Int_t npointsT = 0;
 722   fitterT2.ClearPoints();
 723
 724   for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
 725 //              printf("\nLayer %d\n", iLayer);
 726 //     cseed[iLayer].Print();
 727                 if (!cseed[iLayer].IsOK()) continue;
 728     Double_t tilt = cseed[iLayer].fTilt;
 729
 730     for (Int_t itime = 0; itime < nTimeBins+1; itime++) {
 731 //                      printf("\ttime %d\n", itime);
 732       if (!cseed[iLayer].fUsable[itime]) continue;
 733       // x relative to the midle chamber
 734       Double_t x = cseed[iLayer].fX[itime] + cseed[iLayer].fX0 - xref2;
 735       Double_t y = cseed[iLayer].fY[itime];
 736       Double_t z = cseed[iLayer].fZ[itime];
 737
 738       //
 739       // Tilted rieman
 740       //
 741       Double_t uvt[6];
 742       Double_t x2 = cseed[iLayer].fX[itime] + cseed[iLayer].fX0;      // Global x
 743       Double_t t  = 1.0 / (x2*x2 + y*y);
 744       uvt[1]  = t;
 745       uvt[0]  = 2.0 * x2   * uvt[1];
 746       uvt[2]  = 2.0 * tilt * uvt[1];
 747       uvt[3]  = 2.0 * tilt *uvt[1] * x;
 748       uvt[4]  = 2.0 * (y + tilt * z) * uvt[1];
 749
 750       Double_t error = 2.0 * uvt[1];
 751       error *= terror ? cseed[iLayer].fSigmaY : .2;
 752
 753 //                      printf("\tadd point :\n");
 754 //                      for(int i=0; i<5; i++) printf("%f ", uvt[i]);
 755 //                      printf("\n");
 756       fitterT2.AddPoint(uvt,uvt[4],error);
 757       npointsT++;
 758
 759     }
 760
 761   }
 762   fitterT2.Eval();
 763   Double_t rpolz0 = fitterT2.GetParameter(3);
 764   Double_t rpolz1 = fitterT2.GetParameter(4);
 765
 766   //
 767   // Linear fitter  - not possible to make boundaries
 768   // non accept non possible z and dzdx combination
 769   //
 770   Bool_t acceptablez = kTRUE;
 771   for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
 772     if (cseed[iLayer].IsOK()) {
 773       Double_t zT2 = rpolz0 + rpolz1 * (cseed[iLayer].fX0 - xref2);
 774       if (TMath::Abs(cseed[iLayer].fZProb - zT2) > cseed[iLayer].fPadLength * 0.5 + 1.0) {
 775         acceptablez = kFALSE;
 776       }
 777     }
 778   }
 779   if (!acceptablez) {
 780     Double_t zmf  = cseed[2].fZref[0] + cseed[2].fZref[1] * (xref2 - cseed[2].fX0);
 781     Double_t dzmf = (cseed[2].fZref[1] + cseed[3].fZref[1]) * 0.5;
 782     fitterT2.FixParameter(3,zmf);
 783     fitterT2.FixParameter(4,dzmf);
 784     fitterT2.Eval();
 785     fitterT2.ReleaseParameter(3);
 786     fitterT2.ReleaseParameter(4);
 787     rpolz0 = fitterT2.GetParameter(3);
 788     rpolz1 = fitterT2.GetParameter(4);
 789   }
 790
 791   Double_t chi2TR = fitterT2.GetChisquare() / Float_t(npointsT);
 792   Double_t params[3];
 793   params[0] =  fitterT2.GetParameter(0);
 794   params[1] =  fitterT2.GetParameter(1);
 795   params[2] =  fitterT2.GetParameter(2);
 796   Double_t curvature =  1.0 + params[1] * params[1] - params[2] * params[0];
 797
 798   for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
 799
 800     Double_t  x  = cseed[iLayer].fX0;
 801     Double_t  y  = 0;
 802     Double_t  dy = 0;
 803     Double_t  z  = 0;
 804     Double_t  dz = 0;
 805
 806     // y
 807     Double_t res2 = (x * params[0] + params[1]);
 808     res2 *= res2;
 809     res2  = 1.0 - params[2]*params[0] + params[1]*params[1] - res2;
 810     if (res2 >= 0) {
 811       res2 = TMath::Sqrt(res2);
 812       y    = (1.0 - res2) / params[0];
 813     }
 814
 815     //dy
 816     Double_t x0 = -params[1] / params[0];
 817     if (-params[2]*params[0] + params[1]*params[1] + 1 > 0) {
 818       Double_t rm1 = params[0] / TMath::Sqrt(-params[2]*params[0] + params[1]*params[1] + 1);
 819       if (1.0/(rm1*rm1) - (x-x0) * (x-x0) > 0.0) {
 820                                 Double_t res = (x - x0) / TMath::Sqrt(1.0 / (rm1*rm1) - (x-x0)*(x-x0));
 821                                 if (params[0] < 0) res *= -1.0;
 822                                 dy = res;
 823       }
 824     }
 825     z  = rpolz0 + rpolz1 * (x - xref2);
 826     dz = rpolz1;
 827     cseed[iLayer].fYref[0] = y;
 828     cseed[iLayer].fYref[1] = dy;
 829     cseed[iLayer].fZref[0] = z;
 830     cseed[iLayer].fZref[1] = dz;
 831     cseed[iLayer].fC       = curvature;
 832
 833   }
 834
 835   return chi2TR;
 836
 837 }
 838
 839 //___________________________________________________________________
 840 void AliTRDseedV1::Print()
 841 {
 842   //
 843   // Printing the seedstatus
 844   //
 845
 846         AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
 847         Int_t nTimeBins = cal->GetNumberOfTimeBins();
 848
 849         printf("Seed status :\n");
 850         printf("  fTilt      = %f\n", fTilt);
 851         printf("  fPadLength = %f\n", fPadLength);
 852         printf("  fX0        = %f\n", fX0);
 853         for(int ic=0; ic<nTimeBins; ic++) {
 854           const Char_t *isUsable = fUsable[ic]?"Yes":"No";
 855           printf("  %d X[%f] Y[%f] Z[%f] Indexes[%d] clusters[%p] usable[%s]\n"
 856                 , ic
 857                 , fX[ic]
 858                 , fY[ic]
 859                 , fZ[ic]
 860                 , fIndexes[ic]
 861                 , ((void*) fClusters[ic])
 862                 , isUsable);
 863         }
 864
 865         printf("  fYref[0] =%f fYref[1] =%f\n", fYref[0], fYref[1]);
 866         printf("  fZref[0] =%f fZref[1] =%f\n", fZref[0], fZref[1]);
 867         printf("  fYfit[0] =%f fYfit[1] =%f\n", fYfit[0], fYfit[1]);
 868         printf("  fYfitR[0]=%f fYfitR[1]=%f\n", fYfitR[0], fYfitR[1]);
 869         printf("  fZfit[0] =%f fZfit[1] =%f\n", fZfit[0], fZfit[1]);
 870         printf("  fZfitR[0]=%f fZfitR[1]=%f\n", fZfitR[0], fZfitR[1]);
 871         printf("  fSigmaY =%f\n", fSigmaY);
 872         printf("  fSigmaY2=%f\n", fSigmaY2);
 873         printf("  fMeanz  =%f\n", fMeanz);
 874         printf("  fZProb  =%f\n", fZProb);
 875         printf("  fLabels[0]=%d fLabels[1]=%d\n", fLabels[0], fLabels[1]);
 876         printf("  fN      =%d\n", fN);
 877         printf("  fN2     =%d (>8 isOK)\n",fN2);
 878         printf("  fNUsed  =%d\n", fNUsed);
 879         printf("  fFreq   =%d\n", fFreq);
 880         printf("  fNChange=%d\n",  fNChange);
 881         printf("  fMPads  =%f\n", fMPads);
 882
 883         printf("  fC      =%f\n", fC);
 884         printf("  fCC     =%f\n",fCC);
 885         printf("  fChi2   =%f\n", fChi2);
 886         printf("  fChi2Z  =%f\n", fChi2Z);
 887
 888 }