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 "AliRunLoader.h"
  31 #include "AliLoader.h"
  32 #include "AliRawReader.h"
  33 #include "AliLog.h"
  34
  35 #include "AliTRDclusterizerV1.h"
  36 #include "AliTRDgeometry.h"
  37 #include "AliTRDdataArrayF.h"
  38 #include "AliTRDdataArrayI.h"
  39 #include "AliTRDdigitsManager.h"
  40 #include "AliTRDpadPlane.h"
  41 #include "AliTRDrawData.h"
  42 #include "AliTRDcalibDB.h"
  43 #include "AliTRDSimParam.h"
  44 #include "AliTRDRecParam.h"
  45 #include "AliTRDCommonParam.h"
  46 #include "AliTRDcluster.h"
  47
  48 ClassImp(AliTRDclusterizerV1)
  49
  50 //_____________________________________________________________________________
  51 AliTRDclusterizerV1::AliTRDclusterizerV1()
  52   :AliTRDclusterizer()
  53   ,fDigitsManager(NULL)
  54 {
  55   //
  56   // AliTRDclusterizerV1 default constructor
  57   //
  58
  59 }
  60
  61 //_____________________________________________________________________________
  62 AliTRDclusterizerV1::AliTRDclusterizerV1(const Text_t *name, const Text_t *title)
  63   :AliTRDclusterizer(name,title)
  64   ,fDigitsManager(new AliTRDdigitsManager())
  65 {
  66   //
  67   // AliTRDclusterizerV1 constructor
  68   //
  69
  70   fDigitsManager->CreateArrays();
  71
  72 }
  73
  74 //_____________________________________________________________________________
  75 AliTRDclusterizerV1::AliTRDclusterizerV1(const AliTRDclusterizerV1 &c)
  76   :AliTRDclusterizer(c)
  77   ,fDigitsManager(NULL)
  78 {
  79   //
  80   // AliTRDclusterizerV1 copy constructor
  81   //
  82
  83 }
  84
  85 //_____________________________________________________________________________
  86 AliTRDclusterizerV1::~AliTRDclusterizerV1()
  87 {
  88   //
  89   // AliTRDclusterizerV1 destructor
  90   //
  91
  92   if (fDigitsManager) {
  93     delete fDigitsManager;
  94     fDigitsManager = NULL;
  95   }
  96
  97 }
  98
  99 //_____________________________________________________________________________
 100 AliTRDclusterizerV1 &AliTRDclusterizerV1::operator=(const AliTRDclusterizerV1 &c)
 101 {
 102   //
 103   // Assignment operator
 104   //
 105
 106   if (this != &c) ((AliTRDclusterizerV1 &) c).Copy(*this);
 107   return *this;
 108
 109 }
 110
 111 //_____________________________________________________________________________
 112 void AliTRDclusterizerV1::Copy(TObject &c) const
 113 {
 114   //
 115   // Copy function
 116   //
 117
 118   ((AliTRDclusterizerV1 &) c).fDigitsManager = 0;
 119
 120   AliTRDclusterizer::Copy(c);
 121
 122 }
 123
 124 //_____________________________________________________________________________
 125 Bool_t AliTRDclusterizerV1::ReadDigits()
 126 {
 127   //
 128   // Reads the digits arrays from the input aliroot file
 129   //
 130
 131   if (!fRunLoader) {
 132     AliError("No run loader available");
 133     return kFALSE;
 134   }
 135
 136   AliLoader* loader = fRunLoader->GetLoader("TRDLoader");
 137   if (!loader->TreeD()) {
 138     loader->LoadDigits();
 139   }
 140
 141   // Read in the digit arrays
 142   return (fDigitsManager->ReadDigits(loader->TreeD()));
 143
 144 }
 145
 146 //_____________________________________________________________________________
 147 Bool_t AliTRDclusterizerV1::ReadDigits(AliRawReader *rawReader)
 148 {
 149   //
 150   // Reads the digits arrays from the ddl file
 151   //
 152
 153   AliTRDrawData raw;
 154   fDigitsManager = raw.Raw2Digits(rawReader);
 155
 156   return kTRUE;
 157
 158 }
 159
 160 //_____________________________________________________________________________
 161 Bool_t AliTRDclusterizerV1::MakeClusters()
 162 {
 163   //
 164   // Generates the cluster.
 165   //
 166
 167   Int_t row   = 0;
 168   Int_t col   = 0;
 169   Int_t time  = 0;
 170   Int_t icham = 0;
 171   Int_t iplan = 0;
 172   Int_t isect = 0;
 173   Int_t iPad  = 0;
 174
 175   AliTRDdataArrayI *digitsIn;
 176   AliTRDdataArrayI *tracksIn;
 177
 178   // Get the geometry
 179   AliTRDgeometry *geo            = AliTRDgeometry::GetGeometry(fRunLoader);
 180
 181   AliTRDcalibDB  *calibration    = AliTRDcalibDB::Instance();
 182   if (!calibration) {
 183     AliError("No AliTRDcalibDB instance available\n");
 184     return kFALSE;
 185   }
 186
 187   AliTRDSimParam *simParam       = AliTRDSimParam::Instance();
 188   if (!simParam) {
 189     AliError("No AliTRDSimParam instance available\n");
 190     return kFALSE;
 191   }
 192
 193   AliTRDRecParam *recParam       = AliTRDRecParam::Instance();
 194   if (!recParam) {
 195     AliError("No AliTRDRecParam instance available\n");
 196     return kFALSE;
 197   }
 198
 199   AliTRDCommonParam *commonParam = AliTRDCommonParam::Instance();
 200   if (!commonParam) {
 201     AliError("Could not get common parameters\n");
 202     return kFALSE;
 203   }
 204
 205   // ADC threshols
 206   Float_t ADCthreshold   = simParam->GetADCthreshold();
 207   // Threshold value for the maximum
 208   Float_t maxThresh      = recParam->GetClusMaxThresh();
 209   // Threshold value for the digit signal
 210   Float_t sigThresh      = recParam->GetClusSigThresh();
 211
 212   // Iteration limit for unfolding procedure
 213   const Float_t kEpsilon = 0.01;
 214   const Int_t   kNclus   = 3;
 215   const Int_t   kNsig    = 5;
 216   const Int_t   kNdict   = AliTRDdigitsManager::kNDict;
 217   const Int_t   kNtrack  = kNdict * kNclus;
 218
 219   Int_t    iType         = 0;
 220   Int_t    iUnfold       = 0;
 221   Double_t ratioLeft     = 1.0;
 222   Double_t ratioRight    = 1.0;
 223
 224   Int_t    iClusterROC   = 0;
 225
 226   Double_t padSignal[kNsig];
 227   Double_t clusterSignal[kNclus];
 228   Double_t clusterPads[kNclus];
 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   Int_t    dummy[9]   = { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
 239
 240   AliDebug(1,Form("Number of Time Bins = %d.\n",nTimeTotal));
 241
 242   // Start clustering in every chamber
 243   for (icham = chamBeg; icham < chamEnd; icham++) {
 244     for (iplan = planBeg; iplan < planEnd; iplan++) {
 245       for (isect = sectBeg; isect < sectEnd; isect++) {
 246
 247         Int_t idet = geo->GetDetector(iplan,icham,isect);
 248
 249         // Get the digits
 250         digitsIn = fDigitsManager->GetDigits(idet);
 251         // This is to take care of switched off super modules
 252         if (digitsIn->GetNtime() == 0) {
 253           continue;
 254         }
 255         digitsIn->Expand();
 256         AliTRDdataArrayI *tracksTmp = fDigitsManager->GetDictionary(idet,0);
 257         tracksTmp->Expand();
 258
 259         Int_t nRowMax = commonParam->GetRowMax(iplan,icham,isect);
 260         Int_t nColMax = commonParam->GetColMax(iplan);
 261
 262         AliTRDpadPlane *padPlane = commonParam->GetPadPlane(iplan,icham);
 263
 264         Int_t nClusters      = 0;
 265         Int_t nClusters2pad  = 0;
 266         Int_t nClusters3pad  = 0;
 267         Int_t nClusters4pad  = 0;
 268         Int_t nClusters5pad  = 0;
 269         Int_t nClustersLarge = 0;
 270
 271         // Apply the gain and the tail cancelation via digital filter
 272         AliTRDdataArrayF *digitsOut = new AliTRDdataArrayF(digitsIn->GetNrow()
 273                                                           ,digitsIn->GetNcol()
 274                                                           ,digitsIn->GetNtime());
 275         Transform(digitsIn,digitsOut,idet,nRowMax,nColMax,nTimeTotal,ADCthreshold);
 276
 277         // Input digits are not needed any more
 278         digitsIn->Compress(1,0);
 279
 280         // Loop through the chamber and find the maxima
 281         for ( row = 0;  row <  nRowMax;    row++) {
 282           for ( col = 2;  col <  nColMax;    col++) {
 283             for (time = 0; time < nTimeTotal; time++) {
 284
 285               Float_t signalL = TMath::Abs(digitsOut->GetDataUnchecked(row,col  ,time));
 286               Float_t signalM = TMath::Abs(digitsOut->GetDataUnchecked(row,col-1,time));
 287               Float_t signalR = TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time));
 288
 289               // Look for the maximum
 290               if (signalM >= maxThresh) {
 291                 if ((TMath::Abs(signalL) <= signalM) &&
 292                     (TMath::Abs(signalR) <  signalM)) {
 293                   if ((TMath::Abs(signalL) >= sigThresh) ||
 294                       (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         tracksTmp->Compress(1,0);
 305
 306         // The index to the first cluster of a given ROC
 307         Int_t firstClusterROC = -1;
 308         // The number of cluster in a given ROC
 309         Int_t nClusterROC     =  0;
 310
 311         // Now check the maxima and calculate the cluster position
 312         for ( row = 0;  row <  nRowMax  ;  row++) {
 313           for (time = 0; time < nTimeTotal; time++) {
 314             for ( col = 1;  col <  nColMax-1;  col++) {
 315
 316               // Maximum found ?
 317               if (digitsOut->GetDataUnchecked(row,col,time) < 0.0) {
 318
 319                 for (iPad = 0; iPad < kNclus; iPad++) {
 320                   Int_t iPadCol = col - 1 + iPad;
 321                   clusterSignal[iPad] =
 322                     TMath::Abs(digitsOut->GetDataUnchecked(row,iPadCol,time));
 323                 }
 324
 325                 // Count the number of pads in the cluster
 326                 Int_t nPadCount = 0;
 327                 Int_t ii;
 328                 // Look to the left
 329                 ii = 0;
 330                 while (TMath::Abs(digitsOut->GetDataUnchecked(row,col-ii  ,time)) >= sigThresh) {
 331                   nPadCount++;
 332                   ii++;
 333                   if (col-ii   <        0) break;
 334                 }
 335                 // Look to the right
 336                 ii = 0;
 337                 while (TMath::Abs(digitsOut->GetDataUnchecked(row,col+ii+1,time)) >= sigThresh) {
 338                   nPadCount++;
 339                   ii++;
 340                   if (col+ii+1 >= nColMax) break;
 341                 }
 342                 nClusters++;
 343                 switch (nPadCount) {
 344                 case 2:
 345                   iType = 0;
 346                   nClusters2pad++;
 347                   break;
 348                 case 3:
 349                   iType = 1;
 350                   nClusters3pad++;
 351                   break;
 352                 case 4:
 353                   iType = 2;
 354                   nClusters4pad++;
 355                   break;
 356                 case 5:
 357                   iType = 3;
 358                   nClusters5pad++;
 359                   break;
 360                 default:
 361                   iType = 4;
 362                   nClustersLarge++;
 363                   break;
 364                 };
 365
 366                 // Look for 5 pad cluster with minimum in the middle
 367                 Bool_t fivePadCluster = kFALSE;
 368                 if (col < (nColMax - 3)) {
 369                   if (digitsOut->GetDataUnchecked(row,col+2,time) < 0) {
 370                     fivePadCluster = kTRUE;
 371                   }
 372                   if ((fivePadCluster) && (col < (nColMax - 5))) {
 373                     if (digitsOut->GetDataUnchecked(row,col+4,time) >= sigThresh) {
 374                       fivePadCluster = kFALSE;
 375                     }
 376                   }
 377                   if ((fivePadCluster) && (col >             1)) {
 378                     if (digitsOut->GetDataUnchecked(row,col-2,time) >= sigThresh) {
 379                       fivePadCluster = kFALSE;
 380                     }
 381                   }
 382                 }
 383
 384                 // 5 pad cluster
 385                 // Modify the signal of the overlapping pad for the left part
 386                 // of the cluster which remains from a previous unfolding
 387                 if (iUnfold) {
 388                   clusterSignal[0] *= ratioLeft;
 389                   iType   = 5;
 390                   iUnfold = 0;
 391                 }
 392
 393                 // Unfold the 5 pad cluster
 394                 if (fivePadCluster) {
 395                   for (iPad = 0; iPad < kNsig; iPad++) {
 396                     padSignal[iPad] = TMath::Abs(digitsOut->GetDataUnchecked(row
 397                                                                             ,col-1+iPad
 398                                                                             ,time));
 399                   }
 400                   // Unfold the two maxima and set the signal on
 401                   // the overlapping pad to the ratio
 402                   ratioRight        = Unfold(kEpsilon,iplan,padSignal);
 403                   ratioLeft         = 1.0 - ratioRight;
 404                   clusterSignal[2] *= ratioRight;
 405                   iType   = 5;
 406                   iUnfold = 1;
 407                 }
 408
 409                 Double_t clusterCharge = clusterSignal[0]
 410                                        + clusterSignal[1]
 411                                        + clusterSignal[2];
 412
 413                 // The position of the cluster
 414                 clusterPads[0] =  row + 0.5;
 415                 // Take the shift of the additional time bins into account
 416                 clusterPads[2] = time + 0.5;
 417
 418                 if (recParam->LUTOn()) {
 419                   // Calculate the position of the cluster by using the
 420                   // lookup table method
 421                   clusterPads[1] = recParam->LUTposition(iplan,clusterSignal[0]
 422                                                               ,clusterSignal[1]
 423                                                               ,clusterSignal[2]);
 424                 }
 425                 else {
 426                   // Calculate the position of the cluster by using the
 427                   // center of gravity method
 428                   for (Int_t i = 0; i < kNsig; i++) {
 429                     padSignal[i] = 0.0;
 430                   }
 431                   padSignal[2] = TMath::Abs(digitsOut->GetDataUnchecked(row,col  ,time)); // Central pad
 432                   padSignal[1] = TMath::Abs(digitsOut->GetDataUnchecked(row,col-1,time)); // Left    pad
 433                   padSignal[3] = TMath::Abs(digitsOut->GetDataUnchecked(row,col+1,time)); // Right   pad
 434                   if ((col >           2) &&
 435                       (TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time)) < padSignal[1])) {
 436                     padSignal[0] = TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time));
 437                   }
 438                   if ((col < nColMax - 3) &&
 439                       (TMath::Abs(digitsOut->GetDataUnchecked(row,col+2,time)) < padSignal[3])) {
 440                     padSignal[4] = TMath::Abs(digitsOut->GetDataUnchecked(row,col+2,time));
 441                   }
 442                   clusterPads[1] = GetCOG(padSignal);
 443                 }
 444
 445                 Double_t q0 = clusterSignal[0];
 446                 Double_t q1 = clusterSignal[1];
 447                 Double_t q2 = clusterSignal[2];
 448                 Double_t clusterSigmaY2 = (q1 * (q0 + q2) + 4.0 * q0 * q2)
 449                                         / (clusterCharge*clusterCharge);
 450
 451                 //
 452                 // Calculate the position and the error
 453                 //
 454
 455                 // Correct for t0
 456                 Int_t    clusterTimeBin = TMath::Nint(time - calibration->GetT0(idet,col,row));
 457                 Double_t colSize        = padPlane->GetColSize(col);
 458                 Double_t rowSize        = padPlane->GetRowSize(row);
 459
 460                 Double_t clusterPos[3];
 461                 clusterPos[0] = padPlane->GetColPos(col) - (clusterPads[1] + 0.5) * colSize;
 462                 clusterPos[1] = padPlane->GetRowPos(row) - 0.5                    * rowSize;
 463                 clusterPos[2] = CalcXposFromTimebin(clusterPads[2],idet,col,row);
 464                 Double_t clusterSig[2];
 465                 clusterSig[0] = (clusterSigmaY2 + 1.0/12.0) * colSize*colSize;
 466                 clusterSig[1] = rowSize * rowSize / 12.0;
 467
 468                 // Add the cluster to the output array
 469                 // The track indices will be stored later
 470                 AliTRDcluster *cluster = AddCluster(clusterPos
 471                                                    ,clusterTimeBin
 472                                                    ,idet
 473                                                    ,clusterCharge
 474                                                    ,dummy
 475                                                    ,clusterSig
 476                                                    ,iType
 477                                                    ,clusterPads[1]);
 478
 479                 // Store the amplitudes of the pads in the cluster for later analysis
 480                 Short_t signals[7] = { 0, 0, 0, 0, 0, 0, 0 };
 481                 for (Int_t jPad = col-3; jPad <= col+3; jPad++) {
 482                   if ((jPad <          0) ||
 483                       (jPad >= nColMax-1)) {
 484                     continue;
 485                   }
 486                   signals[jPad-col+3] = TMath::Nint(TMath::Abs(digitsOut->GetDataUnchecked(row,jPad,time)));
 487                 }
 488                 cluster->SetSignals(signals);
 489
 490                 // Temporarily store the row, column and time bin of the center pad
 491                 // Used to later on assign the track indices
 492                 cluster->SetLabel( row,0);
 493                 cluster->SetLabel( col,1);
 494                 cluster->SetLabel(time,2);
 495
 496                 // Store the index of the first cluster in the current ROC
 497                 if (firstClusterROC < 0) {
 498                   firstClusterROC = RecPoints()->GetEntriesFast() - 1;
 499                 }
 500                 // Count the number of cluster in the current ROC
 501                 nClusterROC++;
 502
 503               } // if: Maximum found ?
 504
 505             } // loop: pad columns
 506           } // loop: time bins
 507         } // loop: pad rows
 508
 509         delete digitsOut;
 510
 511         //
 512         // Add the track indices to the found clusters
 513         //
 514
 515         // Temporary array to collect the track indices
 516         Int_t *idxTracks = new Int_t[kNtrack*nClusterROC];
 517
 518         // Loop through the dictionary arrays one-by-one
 519         // to keep memory consumption low
 520         for (Int_t iDict = 0; iDict < kNdict; iDict++) {
 521
 522           tracksIn = fDigitsManager->GetDictionary(idet,iDict);
 523           tracksIn->Expand();
 524
 525           // Loop though the clusters found in this ROC
 526           for (iClusterROC = 0; iClusterROC < nClusterROC; iClusterROC++) {
 527
 528             AliTRDcluster *cluster = (AliTRDcluster *)
 529                                      RecPoints()->UncheckedAt(firstClusterROC+iClusterROC);
 530             row  = cluster->GetLabel(0);
 531             col  = cluster->GetLabel(1);
 532             time = cluster->GetLabel(2);
 533
 534             for (iPad = 0; iPad < kNclus; iPad++) {
 535               Int_t iPadCol = col - 1 + iPad;
 536               Int_t index   = tracksIn->GetDataUnchecked(row,iPadCol,time) - 1;
 537               idxTracks[3*iPad+iDict + iClusterROC*kNtrack] = index;
 538             }
 539
 540           }
 541
 542           // Compress the arrays
 543           tracksIn->Compress(1,0);
 544
 545         }
 546
 547         // Copy the track indices into the cluster
 548         // Loop though the clusters found in this ROC
 549         for (iClusterROC = 0; iClusterROC < nClusterROC; iClusterROC++) {
 550
 551           AliTRDcluster *cluster = (AliTRDcluster *)
 552                                    RecPoints()->UncheckedAt(firstClusterROC+iClusterROC);
 553           cluster->SetLabel(-9999,0);
 554           cluster->SetLabel(-9999,1);
 555           cluster->SetLabel(-9999,2);
 556
 557           cluster->AddTrackIndex(&idxTracks[iClusterROC*kNtrack]);
 558
 559         }
 560
 561         delete [] idxTracks;
 562
 563         // Write the cluster and reset the array
 564         WriteClusters(idet);
 565         ResetRecPoints();
 566
 567       } // loop: Sectors
 568     } // loop: Planes
 569   } // loop: Chambers
 570
 571   return kTRUE;
 572
 573 }
 574
 575 //_____________________________________________________________________________
 576 Double_t AliTRDclusterizerV1::GetCOG(Double_t signal[5])
 577 {
 578   //
 579   // Get COG position
 580   // Used for clusters with more than 3 pads - where LUT not applicable
 581   //
 582
 583   Double_t sum = signal[0]
 584                + signal[1]
 585                + signal[2]
 586                + signal[3]
 587                + signal[4];
 588
 589   Double_t res = (0.0 * (-signal[0] + signal[4])
 590                       + (-signal[1] + signal[3])) / sum;
 591
 592   return res;
 593
 594 }
 595
 596 //_____________________________________________________________________________
 597 Double_t AliTRDclusterizerV1::Unfold(Double_t eps, Int_t plane, Double_t *padSignal)
 598 {
 599   //
 600   // Method to unfold neighbouring maxima.
 601   // The charge ratio on the overlapping pad is calculated
 602   // until there is no more change within the range given by eps.
 603   // The resulting ratio is then returned to the calling method.
 604   //
 605
 606   AliTRDcalibDB *calibration = AliTRDcalibDB::Instance();
 607   if (!calibration) {
 608     AliError("No AliTRDcalibDB instance available\n");
 609     return kFALSE;
 610   }
 611
 612   Int_t   irc                = 0;
 613   Int_t   itStep             = 0;                 // Count iteration steps
 614
 615   Double_t ratio             = 0.5;               // Start value for ratio
 616   Double_t prevRatio         = 0.0;               // Store previous ratio
 617
 618   Double_t newLeftSignal[3]  = { 0.0, 0.0, 0.0 }; // Array to store left cluster signal
 619   Double_t newRightSignal[3] = { 0.0, 0.0, 0.0 }; // Array to store right cluster signal
 620   Double_t newSignal[3]      = { 0.0, 0.0, 0.0 };
 621
 622   // Start the iteration
 623   while ((TMath::Abs(prevRatio - ratio) > eps) && (itStep < 10)) {
 624
 625     itStep++;
 626     prevRatio = ratio;
 627
 628     // Cluster position according to charge ratio
 629     Double_t maxLeft  = (ratio*padSignal[2] - padSignal[0])
 630                       / (padSignal[0] + padSignal[1] + ratio*padSignal[2]);
 631     Double_t maxRight = (padSignal[4] - (1-ratio)*padSignal[2])
 632                       / ((1.0 - ratio)*padSignal[2] + padSignal[3] + padSignal[4]);
 633
 634     // Set cluster charge ratio
 635     irc = calibration->PadResponse(1.0,maxLeft ,plane,newSignal);
 636     Double_t ampLeft  = padSignal[1] / newSignal[1];
 637     irc = calibration->PadResponse(1.0,maxRight,plane,newSignal);
 638     Double_t ampRight = padSignal[3] / newSignal[1];
 639
 640     // Apply pad response to parameters
 641     irc = calibration->PadResponse(ampLeft ,maxLeft ,plane,newLeftSignal );
 642     irc = calibration->PadResponse(ampRight,maxRight,plane,newRightSignal);
 643
 644     // Calculate new overlapping ratio
 645     ratio = TMath::Min((Double_t)1.0,newLeftSignal[2] /
 646                                     (newLeftSignal[2] + newRightSignal[0]));
 647
 648   }
 649
 650   return ratio;
 651
 652 }
 653
 654 //_____________________________________________________________________________
 655 void AliTRDclusterizerV1::Transform(AliTRDdataArrayI *digitsIn
 656                                   , AliTRDdataArrayF *digitsOut
 657                                   , Int_t idet, Int_t nRowMax
 658                                   , Int_t nColMax, Int_t nTimeTotal
 659                                   , Float_t ADCthreshold)
 660 {
 661   //
 662   // Apply gain factor
 663   // Apply tail cancelation: Transform digitsIn to digitsOut
 664   //
 665
 666   Int_t iRow  = 0;
 667   Int_t iCol  = 0;
 668   Int_t iTime = 0;
 669
 670   AliTRDRecParam *recParam = AliTRDRecParam::Instance();
 671   if (!recParam) {
 672     AliError("No AliTRDRecParam instance available\n");
 673     return;
 674   }
 675   AliTRDcalibDB *calibration = AliTRDcalibDB::Instance();
 676   if (!calibration) {
 677     AliError("No AliTRDcalibDB instance available\n");
 678     return;
 679   }
 680
 681   Double_t *inADC  = new Double_t[nTimeTotal];  // ADC data before tail cancellation
 682   Double_t *outADC = new Double_t[nTimeTotal];  // ADC data after tail cancellation
 683
 684   AliDebug(1,Form("Tail cancellation (nExp = %d) for detector %d.\n"
 685                  ,recParam->GetTCnexp(),idet));
 686
 687   for (iRow  = 0; iRow  <  nRowMax;   iRow++ ) {
 688     for (iCol  = 0; iCol  <  nColMax;   iCol++ ) {
 689
 690       for (iTime = 0; iTime < nTimeTotal; iTime++) {
 691
 692         //
 693         // Add gain
 694         //
 695         Double_t gain = calibration->GetGainFactor(idet,iCol,iRow);
 696         if (gain == 0.0) {
 697           AliError("Not a valid gain\n");
 698         }
 699         inADC[iTime]   = digitsIn->GetDataUnchecked(iRow,iCol,iTime);
 700         inADC[iTime]  /= gain;
 701         outADC[iTime]  = inADC[iTime];
 702
 703       }
 704
 705       // Apply the tail cancelation via the digital filter
 706       if (recParam->TCOn()) {
 707         DeConvExp(inADC,outADC,nTimeTotal,recParam->GetTCnexp());
 708       }
 709
 710       for (iTime = 0; iTime < nTimeTotal; iTime++) {
 711
 712         // Store the amplitude of the digit if above threshold
 713         if (outADC[iTime] > ADCthreshold) {
 714           digitsOut->SetDataUnchecked(iRow,iCol,iTime,outADC[iTime]);
 715         }
 716
 717       }
 718
 719     }
 720   }
 721
 722   delete [] inADC;
 723   delete [] outADC;
 724
 725   return;
 726
 727 }
 728
 729 //_____________________________________________________________________________
 730 void AliTRDclusterizerV1::DeConvExp(Double_t *source, Double_t *target
 731                                   , Int_t n, Int_t nexp)
 732 {
 733   //
 734   // Tail cancellation by deconvolution for PASA v4 TRF
 735   //
 736
 737   Double_t rates[2];
 738   Double_t coefficients[2];
 739
 740   // Initialization (coefficient = alpha, rates = lambda)
 741   Double_t R1 = 1.0;
 742   Double_t R2 = 1.0;
 743   Double_t C1 = 0.5;
 744   Double_t C2 = 0.5;
 745
 746   if (nexp == 1) {   // 1 Exponentials
 747     R1 = 1.156;
 748     R2 = 0.130;
 749     C1 = 0.066;
 750     C2 = 0.000;
 751   }
 752   if (nexp == 2) {   // 2 Exponentials
 753     R1 = 1.156;
 754     R2 = 0.130;
 755     C1 = 0.114;
 756     C2 = 0.624;
 757   }
 758
 759   coefficients[0] = C1;
 760   coefficients[1] = C2;
 761
 762   Double_t Dt = 0.1;
 763
 764   rates[0] = TMath::Exp(-Dt/(R1));
 765   rates[1] = TMath::Exp(-Dt/(R2));
 766
 767   Int_t i = 0;
 768   Int_t k = 0;
 769
 770   Double_t reminder[2];
 771   Double_t correction;
 772   Double_t result;
 773
 774   // Attention: computation order is important
 775   correction = 0.0;
 776   for (k = 0; k < nexp; k++) {
 777     reminder[k] = 0.0;
 778   }
 779   for (i = 0; i < n; i++) {
 780     result    = (source[i] - correction);    // No rescaling
 781     target[i] = result;
 782
 783     for (k = 0; k < nexp; k++) {
 784       reminder[k] = rates[k] * (reminder[k] + coefficients[k] * result);
 785     }
 786     correction = 0.0;
 787     for (k = 0; k < nexp; k++) {
 788       correction += reminder[k];
 789     }
 790   }
 791
 792 }