TRD/AliTRDclusterizerV1.cxx

   1
   2 /**************************************************************************
   3  * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
   4  *                                                                        *
   5  * Author: The ALICE Off-line Project.                                    *
   6  * Contributors are mentioned in the code where appropriate.              *
   7  *                                                                        *
   8  * Permission to use, copy, modify and distribute this software and its   *
   9  * documentation strictly for non-commercial purposes is hereby granted   *
  10  * without fee, provided that the above copyright notice appears in all   *
  11  * copies and that both the copyright notice and this permission notice   *
  12  * appear in the supporting documentation. The authors make no claims     *
  13  * about the suitability of this software for any purpose. It is          *
  14  * provided "as is" without express or implied warranty.                  *
  15  **************************************************************************/
  16
  17 /* $Id$ */
  18
  19 ///////////////////////////////////////////////////////////////////////////////
  20 //                                                                           //
  21 // TRD cluster finder                                                        //
  22 //                                                                           //
  23 ///////////////////////////////////////////////////////////////////////////////
  24
  25 #include <TF1.h>
  26 #include <TTree.h>
  27 #include <TH1.h>
  28 #include <TFile.h>
  29
  30 #include "AliRun.h"
  31 #include "AliRunLoader.h"
  32 #include "AliLoader.h"
  33 #include "AliRawReader.h"
  34 #include "AliLog.h"
  35
  36 #include "AliTRDclusterizerV1.h"
  37 #include "AliTRDgeometry.h"
  38 #include "AliTRDdataArrayF.h"
  39 #include "AliTRDdataArrayI.h"
  40 #include "AliTRDdigitsManager.h"
  41 #include "AliTRDpadPlane.h"
  42 #include "AliTRDrawData.h"
  43 #include "AliTRDcalibDB.h"
  44 #include "AliTRDSimParam.h"
  45 #include "AliTRDRecParam.h"
  46 #include "AliTRDCommonParam.h"
  47 #include "AliTRDcluster.h"
  48
  49 ClassImp(AliTRDclusterizerV1)
  50
  51 //_____________________________________________________________________________
  52 AliTRDclusterizerV1::AliTRDclusterizerV1()
  53   :AliTRDclusterizer()
  54   ,fDigitsManager(NULL)
  55 {
  56   //
  57   // AliTRDclusterizerV1 default constructor
  58   //
  59
  60 }
  61
  62 //_____________________________________________________________________________
  63 AliTRDclusterizerV1::AliTRDclusterizerV1(const Text_t* name, const Text_t* title)
  64   :AliTRDclusterizer(name,title)
  65   ,fDigitsManager(new AliTRDdigitsManager())
  66 {
  67   //
  68   // AliTRDclusterizerV1 constructor
  69   //
  70
  71   fDigitsManager->CreateArrays();
  72
  73 }
  74
  75 //_____________________________________________________________________________
  76 AliTRDclusterizerV1::AliTRDclusterizerV1(const AliTRDclusterizerV1 &c)
  77   :AliTRDclusterizer(c)
  78   ,fDigitsManager(NULL)
  79 {
  80   //
  81   // AliTRDclusterizerV1 copy constructor
  82   //
  83
  84 }
  85
  86 //_____________________________________________________________________________
  87 AliTRDclusterizerV1::~AliTRDclusterizerV1()
  88 {
  89   //
  90   // AliTRDclusterizerV1 destructor
  91   //
  92
  93   if (fDigitsManager) {
  94     delete fDigitsManager;
  95     fDigitsManager = NULL;
  96   }
  97
  98 }
  99
 100 //_____________________________________________________________________________
 101 AliTRDclusterizerV1 &AliTRDclusterizerV1::operator=(const AliTRDclusterizerV1 &c)
 102 {
 103   //
 104   // Assignment operator
 105   //
 106
 107   if (this != &c) ((AliTRDclusterizerV1 &) c).Copy(*this);
 108   return *this;
 109
 110 }
 111
 112 //_____________________________________________________________________________
 113 void AliTRDclusterizerV1::Copy(TObject &c) const
 114 {
 115   //
 116   // Copy function
 117   //
 118
 119   ((AliTRDclusterizerV1 &) c).fDigitsManager = 0;
 120
 121   AliTRDclusterizer::Copy(c);
 122
 123 }
 124
 125 //_____________________________________________________________________________
 126 Bool_t AliTRDclusterizerV1::ReadDigits()
 127 {
 128   //
 129   // Reads the digits arrays from the input aliroot file
 130   //
 131
 132   if (!fRunLoader) {
 133     AliError("No run loader available");
 134     return kFALSE;
 135   }
 136
 137   AliLoader* loader = fRunLoader->GetLoader("TRDLoader");
 138   if (!loader->TreeD()) {
 139     loader->LoadDigits();
 140   }
 141
 142   // Read in the digit arrays
 143   return (fDigitsManager->ReadDigits(loader->TreeD()));
 144
 145 }
 146
 147 //_____________________________________________________________________________
 148 Bool_t AliTRDclusterizerV1::ReadDigits(AliRawReader* rawReader)
 149 {
 150   //
 151   // Reads the digits arrays from the ddl file
 152   //
 153
 154   AliTRDrawData raw;
 155   fDigitsManager = raw.Raw2Digits(rawReader);
 156
 157   return kTRUE;
 158
 159 }
 160
 161 //_____________________________________________________________________________
 162 Bool_t AliTRDclusterizerV1::MakeClusters()
 163 {
 164   //
 165   // Generates the cluster.
 166   //
 167
 168   Int_t row   = 0;
 169   Int_t col   = 0;
 170   Int_t time  = 0;
 171   Int_t icham = 0;
 172   Int_t iplan = 0;
 173   Int_t isect = 0;
 174   Int_t iPad  = 0;
 175
 176   AliTRDdataArrayI *digitsIn;
 177   AliTRDdataArrayI *track0;
 178   AliTRDdataArrayI *track1;
 179   AliTRDdataArrayI *track2;
 180
 181   // Get the geometry
 182   AliTRDgeometry *geo            = AliTRDgeometry::GetGeometry(fRunLoader);
 183   AliTRDcalibDB  *calibration    = AliTRDcalibDB::Instance();
 184   if (!calibration) {
 185     AliError("No AliTRDcalibDB instance available\n");
 186     return kFALSE;
 187   }
 188
 189   AliTRDSimParam *simParam       = AliTRDSimParam::Instance();
 190   if (!simParam) {
 191     AliError("No AliTRDSimParam instance available\n");
 192     return kFALSE;
 193   }
 194
 195   AliTRDRecParam *recParam       = AliTRDRecParam::Instance();
 196   if (!recParam) {
 197     AliError("No AliTRDRecParam instance available\n");
 198     return kFALSE;
 199   }
 200
 201   AliTRDCommonParam *commonParam = AliTRDCommonParam::Instance();
 202   if (!commonParam) {
 203     AliError("Could not get common parameters\n");
 204     return kFALSE;
 205   }
 206
 207   // ADC threshols
 208   Float_t ADCthreshold = simParam->GetADCthreshold();
 209   // Threshold value for the maximum
 210   Float_t maxThresh    = recParam->GetClusMaxThresh();
 211   // Threshold value for the digit signal
 212   Float_t sigThresh    = recParam->GetClusSigThresh();
 213
 214   // Iteration limit for unfolding procedure
 215   const Float_t kEpsilon = 0.01;
 216   const Int_t   kNclus   = 3;
 217   const Int_t   kNsig    = 5;
 218   const Int_t   kNtrack  = 3 * kNclus;
 219
 220   Int_t    iType         = 0;
 221   Int_t    iUnfold       = 0;
 222   Double_t ratioLeft     = 1.0;
 223   Double_t ratioRight    = 1.0;
 224
 225   Double_t padSignal[kNsig];
 226   Double_t clusterSignal[kNclus];
 227   Double_t clusterPads[kNclus];
 228   Int_t    clusterTracks[kNtrack];
 229
 230   Int_t    chamBeg    = 0;
 231   Int_t    chamEnd    = AliTRDgeometry::Ncham();
 232   Int_t    planBeg    = 0;
 233   Int_t    planEnd    = AliTRDgeometry::Nplan();
 234   Int_t    sectBeg    = 0;
 235   Int_t    sectEnd    = AliTRDgeometry::Nsect();
 236   Int_t    nTimeTotal = calibration->GetNumberOfTimeBins();
 237
 238   AliDebug(1,Form("Number of Time Bins = %d.\n",nTimeTotal));
 239
 240   // Start clustering in every chamber
 241   for (icham = chamBeg; icham < chamEnd; icham++) {
 242     for (iplan = planBeg; iplan < planEnd; iplan++) {
 243       for (isect = sectBeg; isect < sectEnd; isect++) {
 244
 245         Int_t idet    = geo->GetDetector(iplan,icham,isect);
 246
 247         Int_t nRowMax = commonParam->GetRowMax(iplan,icham,isect);
 248         Int_t nColMax = commonParam->GetColMax(iplan);
 249
 250         AliTRDpadPlane *padPlane = commonParam->GetPadPlane(iplan,icham);
 251
 252         Int_t nClusters      = 0;
 253         Int_t nClusters2pad  = 0;
 254         Int_t nClusters3pad  = 0;
 255         Int_t nClusters4pad  = 0;
 256         Int_t nClusters5pad  = 0;
 257         Int_t nClustersLarge = 0;
 258
 259         AliDebug(1,Form("Analyzing chamber %d, plane %d, sector %d.\n"
 260                        ,icham,iplan,isect));
 261
 262         // Get the digits
 263         digitsIn = fDigitsManager->GetDigits(idet);
 264         // This is to take care of switched off super modules
 265         if (digitsIn->GetNtime() == 0) {
 266           continue;
 267         }
 268         digitsIn->Expand();
 269         track0   = fDigitsManager->GetDictionary(idet,0);
 270         track0->Expand();
 271         track1   = fDigitsManager->GetDictionary(idet,1);
 272         track1->Expand();
 273         track2   = fDigitsManager->GetDictionary(idet,2);
 274         track2->Expand();
 275
 276         AliTRDdataArrayF *digitsOut = new AliTRDdataArrayF(digitsIn->GetNrow()
 277                                                           ,digitsIn->GetNcol()
 278                                                           ,digitsIn->GetNtime());
 279         Transform(digitsIn, digitsOut,idet,nRowMax,nColMax,nTimeTotal,ADCthreshold);
 280
 281         // Loop through the chamber and find the maxima
 282         for ( row = 0;  row <  nRowMax;    row++) {
 283           for ( col = 2;  col <  nColMax;    col++) {
 284             for (time = 0; time < nTimeTotal; time++) {
 285
 286               Float_t signalL = TMath::Abs(digitsOut->GetDataUnchecked(row,col  ,time));
 287               Float_t signalM = TMath::Abs(digitsOut->GetDataUnchecked(row,col-1,time));
 288               Float_t signalR = TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time));
 289
 290               // Look for the maximum
 291               if (signalM >= maxThresh) {
 292                 if ((TMath::Abs(signalL) <= signalM) &&
 293                     (TMath::Abs(signalR) <= signalM) &&
 294                     ((TMath::Abs(signalL) + TMath::Abs(signalR)) > sigThresh)) {
 295                   // Maximum found, mark the position by a negative signal
 296                   digitsOut->SetDataUnchecked(row,col-1,time,-signalM);
 297                 }
 298               }
 299
 300             }
 301           }
 302         }
 303
 304         // Now check the maxima and calculate the cluster position
 305         for ( row = 0;  row <  nRowMax  ;  row++) {
 306           for (time = 0; time < nTimeTotal; time++) {
 307             for ( col = 1;  col <  nColMax-1;  col++) {
 308
 309               // Maximum found ?
 310               if (digitsOut->GetDataUnchecked(row,col,time) < 0) {
 311
 312                 for (iPad = 0; iPad < kNclus; iPad++) {
 313                   Int_t iPadCol = col - 1 + iPad;
 314                   clusterSignal[iPad]     = TMath::Abs(digitsOut->GetDataUnchecked(row
 315                                                                                   ,iPadCol
 316                                                                                    ,time));
 317                   clusterTracks[3*iPad  ] = track0->GetDataUnchecked(row,iPadCol,time) - 1;
 318                   clusterTracks[3*iPad+1] = track1->GetDataUnchecked(row,iPadCol,time) - 1;
 319                   clusterTracks[3*iPad+2] = track2->GetDataUnchecked(row,iPadCol,time) - 1;
 320                 }
 321
 322                 // Count the number of pads in the cluster
 323                 Int_t nPadCount = 0;
 324                 Int_t ii        = 0;
 325                 while (TMath::Abs(digitsOut->GetDataUnchecked(row,col-ii  ,time)) >= sigThresh) {
 326                   nPadCount++;
 327                   ii++;
 328                   if (col-ii   <        0) break;
 329                 }
 330                 ii = 0;
 331                 while (TMath::Abs(digitsOut->GetDataUnchecked(row,col+ii+1,time)) >= sigThresh) {
 332                   nPadCount++;
 333                   ii++;
 334                   if (col+ii+1 >= nColMax) break;
 335                 }
 336
 337                 nClusters++;
 338                 switch (nPadCount) {
 339                 case 2:
 340                   iType = 0;
 341                   nClusters2pad++;
 342                   break;
 343                 case 3:
 344                   iType = 1;
 345                   nClusters3pad++;
 346                   break;
 347                 case 4:
 348                   iType = 2;
 349                   nClusters4pad++;
 350                   break;
 351                 case 5:
 352                   iType = 3;
 353                   nClusters5pad++;
 354                   break;
 355                 default:
 356                   iType = 4;
 357                   nClustersLarge++;
 358                   break;
 359                 };
 360
 361                 // Look for 5 pad cluster with minimum in the middle
 362                 Bool_t fivePadCluster = kFALSE;
 363                 if (col < (nColMax - 3)) {
 364                   if (digitsOut->GetDataUnchecked(row,col+2,time) < 0) {
 365                     fivePadCluster = kTRUE;
 366                   }
 367                   if ((fivePadCluster) && (col < (nColMax - 5))) {
 368                     if (digitsOut->GetDataUnchecked(row,col+4,time) >= sigThresh) {
 369                       fivePadCluster = kFALSE;
 370                     }
 371                   }
 372                   if ((fivePadCluster) && (col >             1)) {
 373                     if (digitsOut->GetDataUnchecked(row,col-2,time) >= sigThresh) {
 374                       fivePadCluster = kFALSE;
 375                     }
 376                   }
 377                 }
 378
 379                 // 5 pad cluster
 380                 // Modify the signal of the overlapping pad for the left part
 381                 // of the cluster which remains from a previous unfolding
 382                 if (iUnfold) {
 383                   clusterSignal[0] *= ratioLeft;
 384                   iType   = 5;
 385                   iUnfold = 0;
 386                 }
 387
 388                 // Unfold the 5 pad cluster
 389                 if (fivePadCluster) {
 390                   for (iPad = 0; iPad < kNsig; iPad++) {
 391                     padSignal[iPad] = TMath::Abs(digitsOut->GetDataUnchecked(row
 392                                                                              ,col-1+iPad
 393                                                                              ,time));
 394                   }
 395                   // Unfold the two maxima and set the signal on
 396                   // the overlapping pad to the ratio
 397                   ratioRight        = Unfold(kEpsilon,iplan,padSignal);
 398                   ratioLeft         = 1.0 - ratioRight;
 399                   clusterSignal[2] *= ratioRight;
 400                   iType   = 5;
 401                   iUnfold = 1;
 402                 }
 403
 404                 Double_t clusterCharge = clusterSignal[0]
 405                                        + clusterSignal[1]
 406                                        + clusterSignal[2];
 407
 408                 // The position of the cluster
 409                 clusterPads[0] = row + 0.5;
 410                 // Take the shift of the additional time bins into account
 411                 clusterPads[2] = time + 0.5;
 412
 413                 if (recParam->LUTOn()) {
 414                   // Calculate the position of the cluster by using the
 415                   // lookup table method
 416                   clusterPads[1] = recParam->LUTposition(iplan,clusterSignal[0]
 417                                                               ,clusterSignal[1]
 418                                                               ,clusterSignal[2]);
 419                 }
 420                 else {
 421                   // Calculate the position of the cluster by using the
 422                   // center of gravity method
 423                   for (Int_t i = 0; i < 5; i++) {
 424                     padSignal[i] = 0;
 425                   }
 426                   padSignal[2] = TMath::Abs(digitsOut->GetDataUnchecked(row,col  ,time)); // central  pad
 427                   padSignal[1] = TMath::Abs(digitsOut->GetDataUnchecked(row,col-1,time)); // left     pad
 428                   padSignal[3] = TMath::Abs(digitsOut->GetDataUnchecked(row,col+1,time)); // right    pad
 429                   if ((col >           2) &&
 430                       (TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time)) < padSignal[1])) {
 431                     padSignal[0] = TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time));
 432                   }
 433                   if ((col < nColMax - 3) &&
 434                       (TMath::Abs(digitsOut->GetDataUnchecked(row,col+2,time)) < padSignal[3])) {
 435                     padSignal[4] = TMath::Abs(digitsOut->GetDataUnchecked(row,col+2,time));
 436                   }
 437                   clusterPads[1] = GetCOG(padSignal);
 438                 }
 439
 440                 Double_t q0 = clusterSignal[0];
 441                 Double_t q1 = clusterSignal[1];
 442                 Double_t q2 = clusterSignal[2];
 443                 Double_t clusterSigmaY2 = (q1*(q0+q2)+4*q0*q2) /
 444                                           (clusterCharge*clusterCharge);
 445
 446                 //
 447                 // Calculate the position and the error
 448                 //
 449
 450                 // Correct for t0
 451                 Int_t    clusterTimeBin = TMath::Nint(time - calibration->GetT0(idet, col, row));
 452
 453                 Double_t colSize        = padPlane->GetColSize(col);
 454                 Double_t rowSize        = padPlane->GetRowSize(row);
 455
 456                 Double_t clusterPos[3];
 457                 clusterPos[0] = padPlane->GetColPos(col) - (clusterPads[1]+0.5)*colSize;
 458                 clusterPos[1] = padPlane->GetRowPos(row) - 0.5*rowSize;
 459                 clusterPos[2] = CalcXposFromTimebin(clusterPads[2],idet,col,row);
 460                 Double_t clusterSig[2];
 461                 clusterSig[0] = (clusterSigmaY2 + 1./12.) * colSize*colSize;
 462                 clusterSig[1] = rowSize * rowSize / 12.;
 463
 464
 465                 // Add the cluster to the output array
 466                 AliTRDcluster * cluster = AddCluster(clusterPos
 467                                                     ,clusterTimeBin
 468                                                     ,idet
 469                                                     ,clusterCharge
 470                                                     ,clusterTracks
 471                                                     ,clusterSig
 472                                                     ,iType
 473                                                     ,clusterPads[1]);
 474
 475                 printf("Add a cluster: q=%f, det=%d, x=%f, y=%f, z=%f\n",clusterCharge
 476                        ,idet,clusterPos[0],clusterPos[1],clusterPos[2]);
 477
 478                 Short_t signals[7]={ 0, 0, 0, 0, 0, 0, 0 };
 479                 for (Int_t jPad = col-3; jPad <= col+3; jPad++) {
 480                   if ((jPad < 0) || (jPad >= nColMax-1)) {
 481                     continue;
 482                   }
 483                   signals[jPad-col+3] = TMath::Nint(TMath::Abs(digitsOut->GetDataUnchecked(row,jPad,time)));
 484                 }
 485                 cluster->SetSignals(signals);
 486
 487               }
 488
 489             }
 490           }
 491         }
 492
 493         delete digitsOut;
 494
 495         // Compress the arrays
 496         track0->Compress(1,0);
 497         track1->Compress(1,0);
 498         track2->Compress(1,0);
 499
 500         // Write the cluster and reset the array
 501         WriteClusters(idet);
 502         ResetRecPoints();
 503
 504       }
 505     }
 506   }
 507
 508   return kTRUE;
 509
 510 }
 511
 512 //_____________________________________________________________________________
 513 Double_t AliTRDclusterizerV1::GetCOG(Double_t signal[5])
 514 {
 515   //
 516   // Get COG position
 517   // Used for clusters with more than 3 pads - where LUT not applicable
 518   //
 519
 520   Double_t sum = signal[0]+signal[1]+signal[2]+signal[3]+signal[4];
 521   Double_t res = (0.0*(-signal[0]+signal[4])+(-signal[1]+signal[3]))/sum;
 522
 523   return res;
 524
 525 }
 526
 527 //_____________________________________________________________________________
 528 Double_t AliTRDclusterizerV1::Unfold(Double_t eps, Int_t plane, Double_t* padSignal)
 529 {
 530   //
 531   // Method to unfold neighbouring maxima.
 532   // The charge ratio on the overlapping pad is calculated
 533   // until there is no more change within the range given by eps.
 534   // The resulting ratio is then returned to the calling method.
 535   //
 536
 537   AliTRDcalibDB* calibration = AliTRDcalibDB::Instance();
 538   if (!calibration) {
 539     AliError("No AliTRDcalibDB instance available\n");
 540     return kFALSE;
 541   }
 542
 543   Int_t   irc                = 0;
 544   Int_t   itStep             = 0;      // Count iteration steps
 545
 546   Double_t ratio             = 0.5;    // Start value for ratio
 547   Double_t prevRatio         = 0;      // Store previous ratio
 548
 549   Double_t newLeftSignal[3]  = {0};    // Array to store left cluster signal
 550   Double_t newRightSignal[3] = {0};    // Array to store right cluster signal
 551   Double_t newSignal[3]      = {0};
 552
 553   // Start the iteration
 554   while ((TMath::Abs(prevRatio - ratio) > eps) && (itStep < 10)) {
 555
 556     itStep++;
 557     prevRatio = ratio;
 558
 559     // Cluster position according to charge ratio
 560     Double_t maxLeft  = (ratio*padSignal[2] - padSignal[0])
 561                       / (padSignal[0] + padSignal[1] + ratio*padSignal[2]);
 562     Double_t maxRight = (padSignal[4] - (1-ratio)*padSignal[2])
 563                       / ((1-ratio)*padSignal[2] + padSignal[3] + padSignal[4]);
 564
 565     // Set cluster charge ratio
 566     irc = calibration->PadResponse(1.0,maxLeft ,plane,newSignal);
 567     Double_t ampLeft  = padSignal[1] / newSignal[1];
 568     irc = calibration->PadResponse(1.0,maxRight,plane,newSignal);
 569     Double_t ampRight = padSignal[3] / newSignal[1];
 570
 571     // Apply pad response to parameters
 572     irc = calibration->PadResponse(ampLeft ,maxLeft ,plane,newLeftSignal );
 573     irc = calibration->PadResponse(ampRight,maxRight,plane,newRightSignal);
 574
 575     // Calculate new overlapping ratio
 576     ratio = TMath::Min((Double_t)1.0,newLeftSignal[2] /
 577                           (newLeftSignal[2] + newRightSignal[0]));
 578
 579   }
 580
 581   return ratio;
 582
 583 }
 584
 585 //_____________________________________________________________________________
 586 void AliTRDclusterizerV1::Transform(AliTRDdataArrayI* digitsIn,
 587                                     AliTRDdataArrayF* digitsOut,
 588                                     Int_t idet, Int_t nRowMax,
 589                                     Int_t nColMax, Int_t nTimeTotal,
 590                                     Float_t ADCthreshold)
 591 {
 592   //
 593   // Apply gain factor
 594   // Apply tail cancellation: Transform digitsIn to digitsOut
 595   //
 596
 597   Int_t iRow  = 0;
 598   Int_t iCol  = 0;
 599   Int_t iTime = 0;
 600
 601   AliTRDRecParam* recParam = AliTRDRecParam::Instance();
 602   if (!recParam) {
 603     AliError("No AliTRDRecParam instance available\n");
 604     return;
 605   }
 606   AliTRDcalibDB* calibration = AliTRDcalibDB::Instance();
 607   if (!calibration) {
 608     AliError("No AliTRDcalibDB instance available\n");
 609     return;
 610   }
 611
 612   Double_t *inADC  = new Double_t[nTimeTotal];  // adc data before tail cancellation
 613   Double_t *outADC = new Double_t[nTimeTotal];  // adc data after tail cancellation
 614
 615   AliDebug(1,Form("Tail cancellation (nExp = %d) for detector %d.\n"
 616                  ,recParam->GetTCnexp(),idet));
 617
 618   for (iRow  = 0; iRow  <  nRowMax;   iRow++ ) {
 619     for (iCol  = 0; iCol  <  nColMax;   iCol++ ) {
 620       for (iTime = 0; iTime < nTimeTotal; iTime++) {
 621
 622         //
 623         // Add gain
 624         //
 625         Double_t gain = calibration->GetGainFactor(idet,iCol,iRow);
 626         if (gain == 0) {
 627           AliError("Not a valid gain\n");
 628         }
 629         inADC[iTime]  = digitsIn->GetDataUnchecked(iRow,iCol,iTime);
 630         inADC[iTime] /= gain;
 631         outADC[iTime] = inADC[iTime];
 632
 633       }
 634
 635       // Apply the tail cancelation via the digital filter
 636       if (recParam->TCOn()) {
 637         DeConvExp(inADC,outADC,nTimeTotal,recParam->GetTCnexp());
 638       }
 639
 640       for (iTime = 0; iTime < nTimeTotal; iTime++) {
 641
 642         // Store the amplitude of the digit if above threshold
 643         if (outADC[iTime] > ADCthreshold) {
 644           AliDebug(2,Form("  iRow = %d, iCol = %d, iTime = %d, adc = %f\n"
 645                          ,iRow,iCol,iTime,outADC[iTime]));
 646           digitsOut->SetDataUnchecked(iRow,iCol,iTime,outADC[iTime]);
 647         }
 648
 649       }
 650
 651     }
 652   }
 653
 654   delete [] inADC;
 655   delete [] outADC;
 656
 657   return;
 658
 659 }
 660
 661 //_____________________________________________________________________________
 662 void AliTRDclusterizerV1::DeConvExp(Double_t *source, Double_t *target,
 663                                     Int_t n, Int_t nexp)
 664 {
 665   //
 666   // Tail cancellation by deconvolution for PASA v4 TRF
 667   //
 668
 669   Double_t rates[2];
 670   Double_t coefficients[2];
 671
 672   // Initialization (coefficient = alpha, rates = lambda)
 673   Double_t R1 = 1.0;
 674   Double_t R2 = 1.0;
 675   Double_t C1 = 0.5;
 676   Double_t C2 = 0.5;
 677
 678   if (nexp == 1) {   // 1 Exponentials
 679     R1 = 1.156;
 680     R2 = 0.130;
 681     C1 = 0.066;
 682     C2 = 0.000;
 683   }
 684   if (nexp == 2) {   // 2 Exponentials
 685     R1 = 1.156;
 686     R2 = 0.130;
 687     C1 = 0.114;
 688     C2 = 0.624;
 689   }
 690
 691   coefficients[0] = C1;
 692   coefficients[1] = C2;
 693
 694   Double_t Dt = 0.100;
 695
 696   rates[0] = TMath::Exp(-Dt/(R1));
 697   rates[1] = TMath::Exp(-Dt/(R2));
 698
 699   Int_t i = 0;
 700   Int_t k = 0;
 701
 702   Double_t reminder[2];
 703   Double_t correction;
 704   Double_t result;
 705
 706   // Attention: computation order is important
 707   correction = 0.0;
 708   for (k = 0; k < nexp; k++) {
 709     reminder[k] = 0.0;
 710   }
 711   for (i = 0; i < n; i++) {
 712     result    = (source[i] - correction);    // no rescaling
 713     target[i] = result;
 714
 715     for (k = 0; k < nexp; k++) {
 716       reminder[k] = rates[k] * (reminder[k] + coefficients[k] * result);
 717     }
 718     correction = 0.0;
 719     for (k = 0; k < nexp; k++) {
 720       correction += reminder[k];
 721     }
 722   }
 723
 724 }