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 for the slow simulator.
  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
  35 #include "AliTRDclusterizerV1.h"
  36 #include "AliTRDmatrix.h"
  37 #include "AliTRDgeometry.h"
  38 #include "AliTRDdataArrayF.h"
  39 #include "AliTRDdataArrayI.h"
  40 #include "AliTRDdigitsManager.h"
  41 #include "AliTRDparameter.h"
  42 #include "AliTRDpadPlane.h"
  43 #include "AliTRDrawData.h"
  44 #include "AliTRDcalibDB.h"
  45 #include "AliTRDSimParam.h"
  46 #include "AliTRDRecParam.h"
  47 #include "AliTRDCommonParam.h"
  48 #include "AliTRDcluster.h"
  49
  50 ClassImp(AliTRDclusterizerV1)
  51
  52 //_____________________________________________________________________________
  53 AliTRDclusterizerV1::AliTRDclusterizerV1():AliTRDclusterizer()
  54 {
  55   //
  56   // AliTRDclusterizerV1 default constructor
  57   //
  58
  59   fDigitsManager = 0;
  60
  61 }
  62
  63 //_____________________________________________________________________________
  64 AliTRDclusterizerV1::AliTRDclusterizerV1(const Text_t* name, const Text_t* title)
  65                     :AliTRDclusterizer(name,title)
  66 {
  67   //
  68   // AliTRDclusterizerV1 default constructor
  69   //
  70
  71   fDigitsManager = new AliTRDdigitsManager();
  72   fDigitsManager->CreateArrays();
  73
  74 }
  75
  76 //_____________________________________________________________________________
  77 AliTRDclusterizerV1::AliTRDclusterizerV1(const AliTRDclusterizerV1 &c)
  78 :AliTRDclusterizer(c)
  79 {
  80   //
  81   // AliTRDclusterizerV1 copy constructor
  82   //
  83
  84   ((AliTRDclusterizerV1 &) c).Copy(*this);
  85
  86 }
  87
  88 //_____________________________________________________________________________
  89 AliTRDclusterizerV1::~AliTRDclusterizerV1()
  90 {
  91   //
  92   // AliTRDclusterizerV1 destructor
  93   //
  94
  95   if (fDigitsManager) {
  96     delete fDigitsManager;
  97     fDigitsManager = NULL;
  98   }
  99
 100 }
 101
 102 //_____________________________________________________________________________
 103 AliTRDclusterizerV1 &AliTRDclusterizerV1::operator=(const AliTRDclusterizerV1 &c)
 104 {
 105   //
 106   // Assignment operator
 107   //
 108
 109   if (this != &c) ((AliTRDclusterizerV1 &) c).Copy(*this);
 110   return *this;
 111
 112 }
 113
 114 //_____________________________________________________________________________
 115 void AliTRDclusterizerV1::Copy(TObject &c) const
 116 {
 117   //
 118   // Copy function
 119   //
 120
 121   ((AliTRDclusterizerV1 &) c).fDigitsManager = 0;
 122
 123   AliTRDclusterizer::Copy(c);
 124
 125 }
 126
 127 //_____________________________________________________________________________
 128 Bool_t AliTRDclusterizerV1::ReadDigits()
 129 {
 130   //
 131   // Reads the digits arrays from the input aliroot file
 132   //
 133
 134   if (!fRunLoader) {
 135     printf("<AliTRDclusterizerV1::ReadDigits> ");
 136     printf("No input file open\n");
 137     return kFALSE;
 138   }
 139   AliLoader* loader = fRunLoader->GetLoader("TRDLoader");
 140   if (!loader->TreeD()) loader->LoadDigits();
 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 = new AliTRDrawData();
 155   raw->SetDebug(1);
 156
 157   fDigitsManager = raw->Raw2Digits(rawReader);
 158
 159   return kTRUE;
 160
 161 }
 162
 163 //_____________________________________________________________________________
 164 Bool_t AliTRDclusterizerV1::MakeClusters()
 165 {
 166   //
 167   // Generates the cluster.
 168   //
 169
 170   Int_t row, col, time;
 171
 172   /*
 173   if (fTRD->IsVersion() != 1) {
 174     printf("<AliTRDclusterizerV1::MakeCluster> ");
 175     printf("TRD must be version 1 (slow simulator).\n");
 176     return kFALSE;
 177   }
 178   */
 179
 180   // Get the geometry
 181   AliTRDgeometry *geo = AliTRDgeometry::GetGeometry(fRunLoader);
 182   AliTRDcalibDB* calibration = AliTRDcalibDB::Instance();
 183   if (!calibration)
 184   {
 185     printf("<AliTRDclusterizerV1::MakeCluster> ");
 186     printf("ERROR getting instance of AliTRDcalibDB");
 187     return kFALSE;
 188   }
 189
 190   AliTRDSimParam* simParam = AliTRDSimParam::Instance();
 191   if (!simParam)
 192   {
 193     printf("<AliTRDclusterizerV1::MakeCluster> ");
 194     printf("ERROR getting instance of AliTRDSimParam");
 195     return kFALSE;
 196   }
 197
 198   AliTRDRecParam* recParam = AliTRDRecParam::Instance();
 199   if (!recParam)
 200   {
 201     printf("<AliTRDclusterizerV1::MakeCluster> ");
 202     printf("ERROR getting instance of AliTRDRecParam");
 203     return kFALSE;
 204   }
 205
 206   AliTRDCommonParam* commonParam = AliTRDCommonParam::Instance();
 207   if (!commonParam)
 208   {
 209     printf("<AliTRDclusterizerV1::MakeDigits> ");
 210     printf("Could not get common params\n");
 211     return kFALSE;
 212   }
 213
 214   if (fVerbose > 0) {
 215     //printf("<AliTRDclusterizerV1::MakeCluster> ");
 216     //printf("OmegaTau = %f \n",omegaTau);
 217     printf("<AliTRDclusterizerV1::MakeCluster> ");
 218     printf("Start creating clusters.\n");
 219   }
 220
 221   AliTRDdataArrayI *digitsIn;
 222   AliTRDdataArrayI *digitsOut;    // Should actually be Float_t here (C.L.)!!
 223   AliTRDdataArrayI *track0;
 224   AliTRDdataArrayI *track1;
 225   AliTRDdataArrayI *track2;
 226
 227   // Threshold value for the maximum
 228   Int_t maxThresh = recParam->GetClusMaxThresh();
 229   // Threshold value for the digit signal
 230   Int_t sigThresh = recParam->GetClusSigThresh();
 231   // Iteration limit for unfolding procedure
 232   const Float_t kEpsilon = 0.01;
 233
 234   const Int_t   kNclus   = 3;
 235   const Int_t   kNsig    = 5;
 236   const Int_t   kNtrack  = 3 * kNclus;
 237
 238   Int_t    iType         = 0;
 239   Int_t    iUnfold       = 0;
 240   Double_t ratioLeft     = 1.0;
 241   Double_t ratioRight    = 1.0;
 242
 243   //
 244   Double_t padSignal[kNsig];
 245   Double_t clusterSignal[kNclus];
 246   Double_t clusterPads[kNclus];
 247   Int_t    clusterDigit[kNclus];
 248   Int_t    clusterTracks[kNtrack];
 249
 250   Int_t    chamBeg = 0;
 251   Int_t    chamEnd = AliTRDgeometry::Ncham();
 252   Int_t    planBeg = 0;
 253   Int_t    planEnd = AliTRDgeometry::Nplan();
 254   Int_t    sectBeg = 0;
 255   Int_t    sectEnd = AliTRDgeometry::Nsect();
 256
 257   Int_t    nTimeTotal  = calibration->GetNumberOfTimeBins();
 258
 259   if (fVerbose > 0) {
 260     printf("<AliTRDclusterizerV1::MakeCluster> ");
 261     printf("Number of Time Bins = %d.\n",nTimeTotal);
 262   }
 263
 264
 265   // Start clustering in every chamber
 266   for (Int_t icham = chamBeg; icham < chamEnd; icham++) {
 267     for (Int_t iplan = planBeg; iplan < planEnd; iplan++) {
 268       for (Int_t isect = sectBeg; isect < sectEnd; isect++) {
 269
 270         Int_t idet    = geo->GetDetector(iplan,icham,isect);
 271
 272         Int_t nRowMax = commonParam->GetRowMax(iplan,icham,isect);
 273         Int_t nColMax = commonParam->GetColMax(iplan);
 274
 275         Int_t nClusters      = 0;
 276         Int_t nClusters2pad  = 0;
 277         Int_t nClusters3pad  = 0;
 278         Int_t nClusters4pad  = 0;
 279         Int_t nClusters5pad  = 0;
 280         Int_t nClustersLarge = 0;
 281
 282         if (fVerbose > 0) {
 283           printf("<AliTRDclusterizerV1::MakeCluster> ");
 284           printf("Analyzing chamber %d, plane %d, sector %d.\n"
 285                 ,icham,iplan,isect);
 286         }
 287
 288         AliTRDpadPlane *padPlane = commonParam->GetPadPlane(iplan,icham);
 289
 290         // Get the digits
 291         digitsIn = digitsOut = fDigitsManager->GetDigits(idet);
 292         digitsIn->Expand();
 293         digitsOut->Expand();
 294
 295         Transform(digitsIn, digitsOut, idet, nRowMax, nColMax, nTimeTotal);
 296
 297         track0 = fDigitsManager->GetDictionary(idet,0);
 298         track0->Expand();
 299         track1 = fDigitsManager->GetDictionary(idet,1);
 300         track1->Expand();
 301         track2 = fDigitsManager->GetDictionary(idet,2);
 302         track2->Expand();
 303
 304         // Loop through the chamber and find the maxima
 305         for ( row = 0;  row <  nRowMax;    row++) {
 306           for ( col = 2;  col <  nColMax;    col++) {
 307             //for ( col = 4;  col <  nColMax-2;    col++) {
 308             for (time = 0; time < nTimeTotal; time++) {
 309
 310               Int_t signalL = TMath::Abs(digitsOut->GetDataUnchecked(row,col  ,time));
 311               Int_t signalM = TMath::Abs(digitsOut->GetDataUnchecked(row,col-1,time));
 312               Int_t signalR = TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time));
 313
 314 //            // Look for the maximum
 315 //               if (signalM >= maxThresh) {
 316 //                 if (((signalL >= sigThresh) &&
 317 //                      (signalL <  signalM))  ||
 318 //                     ((signalR >= sigThresh) &&
 319 //                      (signalR <  signalM))) {
 320 //                   // Maximum found, mark the position by a negative signal
 321 //                   digitsOut->SetDataUnchecked(row,col-1,time,-signalM);
 322 //              }
 323 //            }
 324               // Look for the maximum
 325               if (signalM >= maxThresh) {
 326                 if ( (TMath::Abs(signalL)<=signalM) && (TMath::Abs(signalR)<=signalM) &&
 327                      (TMath::Abs(signalL)+TMath::Abs(signalR))>sigThresh ) {
 328                   // Maximum found, mark the position by a negative signal
 329                   digitsOut->SetDataUnchecked(row,col-1,time,-signalM);
 330                 }
 331               }
 332             }
 333           }
 334         }
 335
 336         // Now check the maxima and calculate the cluster position
 337         for ( row = 0;  row <  nRowMax  ;  row++) {
 338           for (time = 0; time < nTimeTotal; time++) {
 339             for ( col = 1;  col <  nColMax-1;  col++) {
 340
 341               // Maximum found ?
 342               if (digitsOut->GetDataUnchecked(row,col,time) < 0) {
 343
 344                 Int_t iPad;
 345                 for (iPad = 0; iPad < kNclus; iPad++) {
 346                   Int_t iPadCol = col - 1 + iPad;
 347                   clusterSignal[iPad]     = TMath::Abs(digitsOut->GetDataUnchecked(row
 348                                                                                ,iPadCol
 349                                                                                ,time));
 350                   clusterDigit[iPad]      = digitsOut->GetIndexUnchecked(row,iPadCol,time);
 351                   clusterTracks[3*iPad  ] = track0->GetDataUnchecked(row,iPadCol,time) - 1;
 352                   clusterTracks[3*iPad+1] = track1->GetDataUnchecked(row,iPadCol,time) - 1;
 353                   clusterTracks[3*iPad+2] = track2->GetDataUnchecked(row,iPadCol,time) - 1;
 354                 }
 355
 356                 // Count the number of pads in the cluster
 357                 Int_t nPadCount = 0;
 358                 Int_t ii        = 0;
 359                 while (TMath::Abs(digitsOut->GetDataUnchecked(row,col-ii  ,time))
 360                                                                   >= sigThresh) {
 361                   nPadCount++;
 362                   ii++;
 363                   if (col-ii   <        0) break;
 364                 }
 365                 ii = 0;
 366                 while (TMath::Abs(digitsOut->GetDataUnchecked(row,col+ii+1,time))
 367                                                                   >= sigThresh) {
 368                   nPadCount++;
 369                   ii++;
 370                   if (col+ii+1 >= nColMax) break;
 371                 }
 372
 373                 nClusters++;
 374                 switch (nPadCount) {
 375                 case 2:
 376                   iType = 0;
 377                   nClusters2pad++;
 378                   break;
 379                 case 3:
 380                   iType = 1;
 381                   nClusters3pad++;
 382                   break;
 383                 case 4:
 384                   iType = 2;
 385                   nClusters4pad++;
 386                   break;
 387                 case 5:
 388                   iType = 3;
 389                   nClusters5pad++;
 390                   break;
 391                 default:
 392                   iType = 4;
 393                   nClustersLarge++;
 394                   break;
 395                 };
 396
 397                  // Look for 5 pad cluster with minimum in the middle
 398                 Bool_t fivePadCluster = kFALSE;
 399                 if (col < nColMax-3) {
 400                   if (digitsOut->GetDataUnchecked(row,col+2,time) < 0) {
 401                     fivePadCluster = kTRUE;
 402                   }
 403                   if ((fivePadCluster) && (col < nColMax-5)) {
 404                     if (digitsOut->GetDataUnchecked(row,col+4,time) >= sigThresh) {
 405                       fivePadCluster = kFALSE;
 406                     }
 407                   }
 408                   if ((fivePadCluster) && (col >         1)) {
 409                     if (digitsOut->GetDataUnchecked(row,col-2,time) >= sigThresh) {
 410                       fivePadCluster = kFALSE;
 411                     }
 412                   }
 413                 }
 414
 415                 // 5 pad cluster
 416                 // Modify the signal of the overlapping pad for the left part
 417                 // of the cluster which remains from a previous unfolding
 418                 if (iUnfold) {
 419                   clusterSignal[0] *= ratioLeft;
 420                   iType   = 5;
 421                   iUnfold = 0;
 422                 }
 423
 424                 // Unfold the 5 pad cluster
 425                 if (fivePadCluster) {
 426                   for (iPad = 0; iPad < kNsig; iPad++) {
 427                     padSignal[iPad] = TMath::Abs(digitsOut->GetDataUnchecked(row
 428                                                                              ,col-1+iPad
 429                                                                              ,time));
 430                   }
 431                   // Unfold the two maxima and set the signal on
 432                   // the overlapping pad to the ratio
 433                   ratioRight        = Unfold(kEpsilon,iplan,padSignal);
 434                   ratioLeft         = 1.0 - ratioRight;
 435                   clusterSignal[2] *= ratioRight;
 436                   iType   = 5;
 437                   iUnfold = 1;
 438                 }
 439
 440
 441                 Double_t clusterCharge = clusterSignal[0]
 442                                        + clusterSignal[1]
 443                                        + clusterSignal[2];
 444
 445                 // The position of the cluster
 446                 clusterPads[0] = row + 0.5;
 447                 // Take the shift of the additional time bins into account
 448                 clusterPads[2] = time + 0.5;
 449
 450
 451                 if (recParam->LUTOn()) {
 452                   // Calculate the position of the cluster by using the
 453                   // lookup table method
 454                   clusterPads[1] = recParam->LUTposition(iplan,clusterSignal[0]
 455                                                          ,clusterSignal[1]
 456                                                          ,clusterSignal[2]);
 457                 }
 458                 else {
 459                   // Calculate the position of the cluster by using the
 460                   // center of gravity method
 461                   for (Int_t i=0;i<5;i++) padSignal[i]=0;
 462                   padSignal[2] = TMath::Abs(digitsOut->GetDataUnchecked(row,col,time));   // central  pad
 463                   padSignal[1] = TMath::Abs(digitsOut->GetDataUnchecked(row,col-1,time)); // left     pad
 464                   padSignal[3] = TMath::Abs(digitsOut->GetDataUnchecked(row,col+1,time)); // right    pad
 465                   if (col>2 &&TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time)<padSignal[1])){
 466                     padSignal[0] = TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time));
 467                   }
 468                   if (col<nColMax-3 &&TMath::Abs(digitsOut->GetDataUnchecked(row,col+2,time)<padSignal[3])){
 469                     padSignal[4] = TMath::Abs(digitsOut->GetDataUnchecked(row,col+2,time));
 470                   }
 471                   clusterPads[1] =  GetCOG(padSignal);
 472
 473                 }
 474
 475                 Double_t q0 = clusterSignal[0];
 476                 Double_t q1 = clusterSignal[1];
 477                 Double_t q2 = clusterSignal[2];
 478                 Double_t clusterSigmaY2 = (q1*(q0+q2)+4*q0*q2) /
 479                                           (clusterCharge*clusterCharge);
 480
 481
 482
 483                 // Calculate the position and the error
 484
 485                 // correct for t0
 486                 Int_t clusterTimeBin = TMath::Nint(time - calibration->GetT0(idet, col, row));
 487
 488                 Double_t colSize = padPlane->GetColSize(col);
 489                 Double_t rowSize = padPlane->GetRowSize(row);
 490                 Double_t clusterPos[3];
 491                 clusterPos[0] = padPlane->GetColPos(col) - (clusterPads[1]+0.5)*colSize;  // MI change
 492                 clusterPos[1] = padPlane->GetRowPos(row) - 0.5*rowSize; //MI change
 493                 clusterPos[2] = CalcXposFromTimebin(clusterPads[2], idet, col, row);
 494                 Double_t clusterSig[2];
 495                 clusterSig[0] = (clusterSigmaY2 + 1./12.) * colSize*colSize;
 496                 clusterSig[1] = rowSize * rowSize / 12.;
 497
 498
 499                 // Add the cluster to the output array
 500                 AliTRDcluster * cluster = AddCluster(clusterPos
 501                           ,clusterTimeBin
 502                           ,idet
 503                           ,clusterCharge
 504                           ,clusterTracks
 505                           ,clusterSig
 506                           ,iType,clusterPads[1]);
 507                 //
 508                 //
 509                 Short_t signals[7]={0,0,0,0,0,0,0};
 510                 for (Int_t jPad = col-3;jPad<=col+3;jPad++){
 511                   if (jPad<0 ||jPad>=nColMax-1) continue;
 512                   signals[jPad-col+3] =  TMath::Abs(digitsOut->GetDataUnchecked(row,jPad,time));
 513                 }
 514                 cluster->SetSignals(signals);
 515               }
 516             }
 517           }
 518         }
 519
 520         // Compress the arrays
 521         digitsOut->Compress(1,0);
 522         track0->Compress(1,0);
 523         track1->Compress(1,0);
 524         track2->Compress(1,0);
 525
 526         // Write the cluster and reset the array
 527         WriteClusters(idet);
 528         ResetRecPoints();
 529       }
 530     }
 531   }
 532
 533   if (fVerbose > 0) {
 534     printf("<AliTRDclusterizerV1::MakeCluster> ");
 535     printf("Done.\n");
 536   }
 537
 538   //delete digitsIn;
 539
 540   return kTRUE;
 541
 542 }
 543
 544 Double_t AliTRDclusterizerV1::GetCOG(Double_t signal[5])
 545 {
 546   //
 547   // get COG position
 548   // used for clusters with more than 3 pads - where LUT not applicable
 549   Double_t sum = signal[0]+signal[1]+signal[2]+signal[3]+signal[4];
 550   Double_t res = (0.0*(-signal[0]+signal[4])+(-signal[1]+signal[3]))/sum;
 551   return res;
 552 }
 553
 554
 555
 556 //_____________________________________________________________________________
 557 Double_t AliTRDclusterizerV1::Unfold(Double_t eps, Int_t plane, Double_t* padSignal)
 558 {
 559   //
 560   // Method to unfold neighbouring maxima.
 561   // The charge ratio on the overlapping pad is calculated
 562   // until there is no more change within the range given by eps.
 563   // The resulting ratio is then returned to the calling method.
 564   //
 565
 566   AliTRDcalibDB* calibration = AliTRDcalibDB::Instance();
 567   if (!calibration)
 568   {
 569     printf("<AliTRDclusterizerMI::Unfold> ");
 570     printf("ERROR getting instance of AliTRDcalibDB");
 571     return kFALSE;
 572   }
 573
 574   Int_t   irc                = 0;
 575   Int_t   itStep             = 0;      // Count iteration steps
 576
 577   Double_t ratio             = 0.5;    // Start value for ratio
 578   Double_t prevRatio         = 0;      // Store previous ratio
 579
 580   Double_t newLeftSignal[3]  = {0};    // Array to store left cluster signal
 581   Double_t newRightSignal[3] = {0};    // Array to store right cluster signal
 582   Double_t newSignal[3]      = {0};
 583
 584   // Start the iteration
 585   while ((TMath::Abs(prevRatio - ratio) > eps) && (itStep < 10)) {
 586
 587     itStep++;
 588     prevRatio = ratio;
 589
 590     // Cluster position according to charge ratio
 591     Double_t maxLeft  = (ratio*padSignal[2] - padSignal[0])
 592                       / (padSignal[0] + padSignal[1] + ratio*padSignal[2]);
 593     Double_t maxRight = (padSignal[4] - (1-ratio)*padSignal[2])
 594                       / ((1-ratio)*padSignal[2] + padSignal[3] + padSignal[4]);
 595
 596     // Set cluster charge ratio
 597     irc = calibration->PadResponse(1.0,maxLeft ,plane,newSignal);
 598     Double_t ampLeft  = padSignal[1] / newSignal[1];
 599     irc = calibration->PadResponse(1.0,maxRight,plane,newSignal);
 600     Double_t ampRight = padSignal[3] / newSignal[1];
 601
 602     // Apply pad response to parameters
 603     irc = calibration->PadResponse(ampLeft ,maxLeft ,plane,newLeftSignal );
 604     irc = calibration->PadResponse(ampRight,maxRight,plane,newRightSignal);
 605
 606     // Calculate new overlapping ratio
 607     ratio = TMath::Min((Double_t)1.0,newLeftSignal[2] /
 608                           (newLeftSignal[2] + newRightSignal[0]));
 609
 610   }
 611
 612   return ratio;
 613
 614 }
 615
 616 //_____________________________________________________________________________
 617 void AliTRDclusterizerV1::Transform(AliTRDdataArrayI* digitsIn,
 618                                     AliTRDdataArrayI* digitsOut,
 619                                     Int_t idet, Int_t nRowMax,
 620                                     Int_t nColMax, Int_t nTimeTotal)
 621 {
 622
 623   //
 624   // Apply gain factor
 625   // Apply tail cancellation: Transform digitsIn to digitsOut
 626   //
 627
 628
 629   AliTRDSimParam* simParam = AliTRDSimParam::Instance();
 630   if (!simParam)
 631   {
 632     printf("<AliTRDclusterizerV1::Transform> ");
 633     printf("ERROR getting instance of AliTRDSimParam");
 634     return;
 635   }
 636   AliTRDcalibDB* calibration = AliTRDcalibDB::Instance();
 637
 638   Double_t *inADC  = new Double_t[nTimeTotal];  // adc data before tail cancellation
 639   Double_t *outADC = new Double_t[nTimeTotal];  // adc data after tail cancellation
 640
 641   if (fVerbose > 0) {
 642     printf("<AliTRDclusterizerV1::Transform> ");
 643     printf("Tail cancellation (nExp = %d) for detector %d.\n",
 644            simParam->GetTCnexp(),idet);
 645   }
 646
 647   for (Int_t iRow  = 0; iRow  <  nRowMax;   iRow++ ) {
 648     for (Int_t iCol  = 0; iCol  <  nColMax;   iCol++ ) {
 649       for (Int_t iTime = 0; iTime < nTimeTotal; iTime++) {
 650         //
 651         // add gain
 652         //
 653         Double_t gain = calibration->GetGainFactor(idet, iCol, iRow);
 654         if (gain==0) {
 655           AliError("Not a valid gain\n");
 656         }
 657         inADC[iTime]  = digitsIn->GetDataUnchecked(iRow, iCol, iTime);
 658         inADC[iTime]  /= gain;
 659         outADC[iTime] = inADC[iTime];
 660
 661       }
 662
 663       // Apply the tail cancelation via the digital filter
 664       if (simParam->TCOn())
 665       {
 666         DeConvExp(inADC,outADC,nTimeTotal,simParam->GetTCnexp());
 667       }
 668
 669       for (Int_t iTime = 0; iTime < nTimeTotal; iTime++) {
 670         // Store the amplitude of the digit if above threshold
 671         if (outADC[iTime] > simParam->GetADCthreshold()) {
 672           if (fVerbose > 1)
 673           {
 674             printf("  iRow = %d, iCol = %d, iTime = %d, adc = %f\n"
 675                    ,iRow,iCol,iTime,outADC[iTime]);
 676           }
 677           digitsOut->SetDataUnchecked(iRow,iCol,iTime,(Int_t)outADC[iTime]);
 678         }
 679
 680       }
 681
 682     }
 683
 684   }
 685
 686   delete [] inADC;
 687   delete [] outADC;
 688
 689   return;
 690
 691 }
 692
 693
 694 //_____________________________________________________________________________
 695 void AliTRDclusterizerV1::DeConvExp(Double_t *source, Double_t *target,
 696                                     Int_t n, Int_t nexp)
 697 {
 698   //
 699   // Tail Cancellation by Deconvolution for PASA v4 TRF
 700   //
 701
 702   Double_t rates[2];
 703   Double_t coefficients[2];
 704
 705   // initialize (coefficient = alpha, rates = lambda)
 706
 707   Double_t R1 = 1.0;
 708   Double_t R2 = 1.0;
 709   Double_t C1 = 0.5;
 710   Double_t C2 = 0.5;
 711
 712   if (nexp == 1) {   // 1 Exponentials
 713     R1 = 1.156;
 714     R2 = 0.130;
 715     C1 = 0.066;
 716     C2 = 0.000;
 717   }
 718   if (nexp == 2) {   // 2 Exponentials
 719     R1 = 1.156;
 720     R2 = 0.130;
 721     C1 = 0.114;
 722     C2 = 0.624;
 723   }
 724
 725   coefficients[0] = C1;
 726   coefficients[1] = C2;
 727
 728   Double_t Dt = 0.100;
 729
 730   rates[0] = TMath::Exp(-Dt/(R1));
 731   rates[1] = TMath::Exp(-Dt/(R2));
 732
 733   Int_t i, k;
 734   Double_t reminder[2];
 735   Double_t correction, result;
 736
 737   /* attention: computation order is important */
 738   correction=0.0;
 739
 740   for ( k=0; k<nexp; k++ ) reminder[k]=0.0;
 741
 742   for ( i=0; i<n; i++ ) {
 743     result = ( source[i] - correction );    // no rescaling
 744     target[i] = result;
 745
 746     for ( k=0; k<nexp; k++ ) reminder[k] = rates[k] *
 747                                ( reminder[k] + coefficients[k] * result);
 748     correction=0.0;
 749     for ( k=0; k<nexp; k++ ) correction += reminder[k];
 750   }
 751
 752 }