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 #include "Cal/AliTRDCalROC.h"
  49 #include "Cal/AliTRDCalDet.h"
  50
  51 ClassImp(AliTRDclusterizerV1)
  52
  53 //_____________________________________________________________________________
  54 AliTRDclusterizerV1::AliTRDclusterizerV1()
  55   :AliTRDclusterizer()
  56   ,fDigitsManager(NULL)
  57 {
  58   //
  59   // AliTRDclusterizerV1 default constructor
  60   //
  61
  62 }
  63
  64 //_____________________________________________________________________________
  65 AliTRDclusterizerV1::AliTRDclusterizerV1(const Text_t *name, const Text_t *title)
  66   :AliTRDclusterizer(name,title)
  67   ,fDigitsManager(new AliTRDdigitsManager())
  68 {
  69   //
  70   // AliTRDclusterizerV1 constructor
  71   //
  72
  73   fDigitsManager->CreateArrays();
  74
  75 }
  76
  77 //_____________________________________________________________________________
  78 AliTRDclusterizerV1::AliTRDclusterizerV1(const AliTRDclusterizerV1 &c)
  79   :AliTRDclusterizer(c)
  80   ,fDigitsManager(NULL)
  81 {
  82   //
  83   // AliTRDclusterizerV1 copy constructor
  84   //
  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     AliError("No run loader available");
 136     return kFALSE;
 137   }
 138
 139   AliLoader* loader = fRunLoader->GetLoader("TRDLoader");
 140   if (!loader->TreeD()) {
 141     loader->LoadDigits();
 142   }
 143
 144   // Read in the digit arrays
 145   return (fDigitsManager->ReadDigits(loader->TreeD()));
 146
 147 }
 148
 149 //_____________________________________________________________________________
 150 Bool_t AliTRDclusterizerV1::ReadDigits(AliRawReader *rawReader)
 151 {
 152   //
 153   // Reads the digits arrays from the ddl file
 154   //
 155
 156   AliTRDrawData raw;
 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   = 0;
 171   Int_t col   = 0;
 172   Int_t time  = 0;
 173   Int_t icham = 0;
 174   Int_t iplan = 0;
 175   Int_t isect = 0;
 176   Int_t iPad  = 0;
 177
 178   AliTRDdataArrayI *digitsIn;
 179   AliTRDdataArrayI *tracksIn;
 180
 181   // Get the geometry
 182   AliTRDgeometry *geo            = AliTRDgeometry::GetGeometry(fRunLoader);
 183
 184   AliTRDcalibDB  *calibration    = AliTRDcalibDB::Instance();
 185   if (!calibration) {
 186     AliFatal("No AliTRDcalibDB instance available\n");
 187     return kFALSE;
 188   }
 189
 190   AliTRDSimParam *simParam       = AliTRDSimParam::Instance();
 191   if (!simParam) {
 192     AliError("No AliTRDSimParam instance available\n");
 193     return kFALSE;
 194   }
 195
 196   AliTRDRecParam *recParam       = AliTRDRecParam::Instance();
 197   if (!recParam) {
 198     AliError("No AliTRDRecParam instance available\n");
 199     return kFALSE;
 200   }
 201
 202   AliTRDCommonParam *commonParam = AliTRDCommonParam::Instance();
 203   if (!commonParam) {
 204     AliError("Could not get common parameters\n");
 205     return kFALSE;
 206   }
 207
 208   // ADC threshols
 209   Float_t ADCthreshold   = simParam->GetADCthreshold();
 210   // Threshold value for the maximum
 211   Float_t maxThresh      = recParam->GetClusMaxThresh();
 212   // Threshold value for the digit signal
 213   Float_t sigThresh      = recParam->GetClusSigThresh();
 214
 215   // Detector wise calibration object for t0
 216   const AliTRDCalDet *calT0Det = calibration->GetT0Det();
 217
 218   // Iteration limit for unfolding procedure
 219   const Float_t kEpsilon = 0.01;
 220   const Int_t   kNclus   = 3;
 221   const Int_t   kNsig    = 5;
 222   const Int_t   kNdict   = AliTRDdigitsManager::kNDict;
 223   const Int_t   kNtrack  = kNdict * kNclus;
 224
 225   Int_t    iType         = 0;
 226   Int_t    iUnfold       = 0;
 227   Double_t ratioLeft     = 1.0;
 228   Double_t ratioRight    = 1.0;
 229
 230   Int_t    iClusterROC   = 0;
 231
 232   Double_t padSignal[kNsig];
 233   Double_t clusterSignal[kNclus];
 234   Double_t clusterPads[kNclus];
 235
 236   Int_t    chamBeg    = 0;
 237   Int_t    chamEnd    = AliTRDgeometry::Ncham();
 238   Int_t    planBeg    = 0;
 239   Int_t    planEnd    = AliTRDgeometry::Nplan();
 240   Int_t    sectBeg    = 0;
 241   Int_t    sectEnd    = AliTRDgeometry::Nsect();
 242   Int_t    nTimeTotal = calibration->GetNumberOfTimeBins();
 243
 244   Int_t    dummy[9]   = { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
 245
 246   AliDebug(1,Form("Number of Time Bins = %d.\n",nTimeTotal));
 247
 248   // Start clustering in every chamber
 249   for (icham = chamBeg; icham < chamEnd; icham++) {
 250     for (iplan = planBeg; iplan < planEnd; iplan++) {
 251       for (isect = sectBeg; isect < sectEnd; isect++) {
 252
 253         Int_t idet = geo->GetDetector(iplan,icham,isect);
 254
 255         // Get the digits
 256         digitsIn = fDigitsManager->GetDigits(idet);
 257         // This is to take care of switched off super modules
 258         if (digitsIn->GetNtime() == 0) {
 259           continue;
 260         }
 261         digitsIn->Expand();
 262         AliTRDdataArrayI *tracksTmp = fDigitsManager->GetDictionary(idet,0);
 263         tracksTmp->Expand();
 264
 265         Int_t nRowMax = commonParam->GetRowMax(iplan,icham,isect);
 266         Int_t nColMax = commonParam->GetColMax(iplan);
 267
 268         AliTRDpadPlane *padPlane = commonParam->GetPadPlane(iplan,icham);
 269
 270         // Calibration object with pad wise values for t0
 271         AliTRDCalROC *calT0ROC      = calibration->GetT0ROC(idet);
 272         // Calibration value for chamber wise t0
 273         Float_t       calT0DetValue = calT0Det->GetValue(idet);
 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         // Apply the gain and the tail cancelation via digital filter
 283         AliTRDdataArrayF *digitsOut = new AliTRDdataArrayF(digitsIn->GetNrow()
 284                                                           ,digitsIn->GetNcol()
 285                                                           ,digitsIn->GetNtime());
 286         Transform(digitsIn,digitsOut,idet,nRowMax,nColMax,nTimeTotal,ADCthreshold);
 287
 288         // Input digits are not needed any more
 289         digitsIn->Compress(1,0);
 290
 291         // Loop through the chamber and find the maxima
 292         for ( row = 0;  row <  nRowMax;    row++) {
 293           for ( col = 2;  col <  nColMax;    col++) {
 294             for (time = 0; time < nTimeTotal; time++) {
 295
 296               Float_t signalL = TMath::Abs(digitsOut->GetDataUnchecked(row,col  ,time));
 297               Float_t signalM = TMath::Abs(digitsOut->GetDataUnchecked(row,col-1,time));
 298               Float_t signalR = TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time));
 299
 300               // Look for the maximum
 301               if (signalM >= maxThresh) {
 302                 if ((TMath::Abs(signalL) <= signalM) &&
 303                     (TMath::Abs(signalR) <  signalM)) {
 304                   if ((TMath::Abs(signalL) >= sigThresh) ||
 305                       (TMath::Abs(signalR) >= sigThresh)) {
 306                     // Maximum found, mark the position by a negative signal
 307                     digitsOut->SetDataUnchecked(row,col-1,time,-signalM);
 308                   }
 309                 }
 310               }
 311
 312             }
 313           }
 314         }
 315         tracksTmp->Compress(1,0);
 316
 317         // The index to the first cluster of a given ROC
 318         Int_t firstClusterROC = -1;
 319         // The number of cluster in a given ROC
 320         Int_t nClusterROC     =  0;
 321
 322         // Now check the maxima and calculate the cluster position
 323         for ( row = 0;  row <  nRowMax  ;  row++) {
 324           for (time = 0; time < nTimeTotal; time++) {
 325             for ( col = 1;  col <  nColMax-1;  col++) {
 326
 327               // Maximum found ?
 328               if (digitsOut->GetDataUnchecked(row,col,time) < 0.0) {
 329
 330                 for (iPad = 0; iPad < kNclus; iPad++) {
 331                   Int_t iPadCol = col - 1 + iPad;
 332                   clusterSignal[iPad] =
 333                     TMath::Abs(digitsOut->GetDataUnchecked(row,iPadCol,time));
 334                 }
 335
 336                 // Count the number of pads in the cluster
 337                 Int_t nPadCount = 0;
 338                 Int_t ii;
 339                 // Look to the left
 340                 ii = 0;
 341                 while (TMath::Abs(digitsOut->GetDataUnchecked(row,col-ii  ,time)) >= sigThresh) {
 342                   nPadCount++;
 343                   ii++;
 344                   if (col-ii   <        0) break;
 345                 }
 346                 // Look to the right
 347                 ii = 0;
 348                 while (TMath::Abs(digitsOut->GetDataUnchecked(row,col+ii+1,time)) >= sigThresh) {
 349                   nPadCount++;
 350                   ii++;
 351                   if (col+ii+1 >= nColMax) break;
 352                 }
 353                 nClusters++;
 354                 switch (nPadCount) {
 355                 case 2:
 356                   iType = 0;
 357                   nClusters2pad++;
 358                   break;
 359                 case 3:
 360                   iType = 1;
 361                   nClusters3pad++;
 362                   break;
 363                 case 4:
 364                   iType = 2;
 365                   nClusters4pad++;
 366                   break;
 367                 case 5:
 368                   iType = 3;
 369                   nClusters5pad++;
 370                   break;
 371                 default:
 372                   iType = 4;
 373                   nClustersLarge++;
 374                   break;
 375                 };
 376
 377                 // Look for 5 pad cluster with minimum in the middle
 378                 Bool_t fivePadCluster = kFALSE;
 379                 if (col < (nColMax - 3)) {
 380                   if (digitsOut->GetDataUnchecked(row,col+2,time) < 0) {
 381                     fivePadCluster = kTRUE;
 382                   }
 383                   if ((fivePadCluster) && (col < (nColMax - 5))) {
 384                     if (digitsOut->GetDataUnchecked(row,col+4,time) >= sigThresh) {
 385                       fivePadCluster = kFALSE;
 386                     }
 387                   }
 388                   if ((fivePadCluster) && (col >             1)) {
 389                     if (digitsOut->GetDataUnchecked(row,col-2,time) >= sigThresh) {
 390                       fivePadCluster = kFALSE;
 391                     }
 392                   }
 393                 }
 394
 395                 // 5 pad cluster
 396                 // Modify the signal of the overlapping pad for the left part
 397                 // of the cluster which remains from a previous unfolding
 398                 if (iUnfold) {
 399                   clusterSignal[0] *= ratioLeft;
 400                   iType   = 5;
 401                   iUnfold = 0;
 402                 }
 403
 404                 // Unfold the 5 pad cluster
 405                 if (fivePadCluster) {
 406                   for (iPad = 0; iPad < kNsig; iPad++) {
 407                     padSignal[iPad] = TMath::Abs(digitsOut->GetDataUnchecked(row
 408                                                                             ,col-1+iPad
 409                                                                             ,time));
 410                   }
 411                   // Unfold the two maxima and set the signal on
 412                   // the overlapping pad to the ratio
 413                   ratioRight        = Unfold(kEpsilon,iplan,padSignal);
 414                   ratioLeft         = 1.0 - ratioRight;
 415                   clusterSignal[2] *= ratioRight;
 416                   iType   = 5;
 417                   iUnfold = 1;
 418                 }
 419
 420                 Double_t clusterCharge = clusterSignal[0]
 421                                        + clusterSignal[1]
 422                                        + clusterSignal[2];
 423
 424                 // The position of the cluster
 425                 clusterPads[0] =  row + 0.5;
 426                 // Take the shift of the additional time bins into account
 427                 clusterPads[2] = time + 0.5;
 428
 429                 if (recParam->LUTOn()) {
 430                   // Calculate the position of the cluster by using the
 431                   // lookup table method
 432                   clusterPads[1] = recParam->LUTposition(iplan,clusterSignal[0]
 433                                                               ,clusterSignal[1]
 434                                                               ,clusterSignal[2]);
 435                 }
 436                 else {
 437                   // Calculate the position of the cluster by using the
 438                   // center of gravity method
 439                   for (Int_t i = 0; i < kNsig; i++) {
 440                     padSignal[i] = 0.0;
 441                   }
 442                   padSignal[2] = TMath::Abs(digitsOut->GetDataUnchecked(row,col  ,time)); // Central pad
 443                   padSignal[1] = TMath::Abs(digitsOut->GetDataUnchecked(row,col-1,time)); // Left    pad
 444                   padSignal[3] = TMath::Abs(digitsOut->GetDataUnchecked(row,col+1,time)); // Right   pad
 445                   if ((col >           2) &&
 446                       (TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time)) < padSignal[1])) {
 447                     padSignal[0] = TMath::Abs(digitsOut->GetDataUnchecked(row,col-2,time));
 448                   }
 449                   if ((col < nColMax - 3) &&
 450                       (TMath::Abs(digitsOut->GetDataUnchecked(row,col+2,time)) < padSignal[3])) {
 451                     padSignal[4] = TMath::Abs(digitsOut->GetDataUnchecked(row,col+2,time));
 452                   }
 453                   clusterPads[1] = GetCOG(padSignal);
 454                 }
 455
 456                 Double_t q0 = clusterSignal[0];
 457                 Double_t q1 = clusterSignal[1];
 458                 Double_t q2 = clusterSignal[2];
 459                 Double_t clusterSigmaY2 = (q1 * (q0 + q2) + 4.0 * q0 * q2)
 460                                         / (clusterCharge*clusterCharge);
 461
 462                 //
 463                 // Calculate the position and the error
 464                 //
 465
 466                 // Correct for t0 (sum of chamber and pad wise values !!!)
 467                 Float_t  calT0ROCValue  = calT0ROC->GetValue(col,row);
 468                 Int_t    clusterTimeBin = TMath::Nint(time - (calT0DetValue + calT0ROCValue));
 469                 Double_t colSize        = padPlane->GetColSize(col);
 470                 Double_t rowSize        = padPlane->GetRowSize(row);
 471
 472                 Double_t clusterPos[3];
 473                 clusterPos[0] = padPlane->GetColPos(col) - (clusterPads[1] + 0.5) * colSize;
 474                 clusterPos[1] = padPlane->GetRowPos(row) - 0.5                    * rowSize;
 475                 clusterPos[2] = CalcXposFromTimebin(clusterPads[2],idet,col,row);
 476                 Double_t clusterSig[2];
 477                 clusterSig[0] = (clusterSigmaY2 + 1.0/12.0) * colSize*colSize;
 478                 clusterSig[1] = rowSize * rowSize / 12.0;
 479
 480                 // Add the cluster to the output array
 481                 // The track indices will be stored later
 482                 AliTRDcluster *cluster = AddCluster(clusterPos
 483                                                    ,clusterTimeBin
 484                                                    ,idet
 485                                                    ,clusterCharge
 486                                                    ,dummy
 487                                                    ,clusterSig
 488                                                    ,iType
 489                                                    ,clusterPads[1]);
 490
 491                 // Store the amplitudes of the pads in the cluster for later analysis
 492                 Short_t signals[7] = { 0, 0, 0, 0, 0, 0, 0 };
 493                 for (Int_t jPad = col-3; jPad <= col+3; jPad++) {
 494                   if ((jPad <          0) ||
 495                       (jPad >= nColMax-1)) {
 496                     continue;
 497                   }
 498                   signals[jPad-col+3] = TMath::Nint(TMath::Abs(digitsOut->GetDataUnchecked(row,jPad,time)));
 499                 }
 500                 cluster->SetSignals(signals);
 501
 502                 // Temporarily store the row, column and time bin of the center pad
 503                 // Used to later on assign the track indices
 504                 cluster->SetLabel( row,0);
 505                 cluster->SetLabel( col,1);
 506                 cluster->SetLabel(time,2);
 507
 508                 // Store the index of the first cluster in the current ROC
 509                 if (firstClusterROC < 0) {
 510                   firstClusterROC = RecPoints()->GetEntriesFast() - 1;
 511                 }
 512                 // Count the number of cluster in the current ROC
 513                 nClusterROC++;
 514
 515               } // if: Maximum found ?
 516
 517             } // loop: pad columns
 518           } // loop: time bins
 519         } // loop: pad rows
 520
 521         delete digitsOut;
 522
 523         //
 524         // Add the track indices to the found clusters
 525         //
 526
 527         // Temporary array to collect the track indices
 528         Int_t *idxTracks = new Int_t[kNtrack*nClusterROC];
 529
 530         // Loop through the dictionary arrays one-by-one
 531         // to keep memory consumption low
 532         for (Int_t iDict = 0; iDict < kNdict; iDict++) {
 533
 534           tracksIn = fDigitsManager->GetDictionary(idet,iDict);
 535           tracksIn->Expand();
 536
 537           // Loop though the clusters found in this ROC
 538           for (iClusterROC = 0; iClusterROC < nClusterROC; iClusterROC++) {
 539
 540             AliTRDcluster *cluster = (AliTRDcluster *)
 541                                      RecPoints()->UncheckedAt(firstClusterROC+iClusterROC);
 542             row  = cluster->GetLabel(0);
 543             col  = cluster->GetLabel(1);
 544             time = cluster->GetLabel(2);
 545
 546             for (iPad = 0; iPad < kNclus; iPad++) {
 547               Int_t iPadCol = col - 1 + iPad;
 548               Int_t index   = tracksIn->GetDataUnchecked(row,iPadCol,time) - 1;
 549               idxTracks[3*iPad+iDict + iClusterROC*kNtrack] = index;
 550             }
 551
 552           }
 553
 554           // Compress the arrays
 555           tracksIn->Compress(1,0);
 556
 557         }
 558
 559         // Copy the track indices into the cluster
 560         // Loop though the clusters found in this ROC
 561         for (iClusterROC = 0; iClusterROC < nClusterROC; iClusterROC++) {
 562
 563           AliTRDcluster *cluster = (AliTRDcluster *)
 564                                    RecPoints()->UncheckedAt(firstClusterROC+iClusterROC);
 565           cluster->SetLabel(-9999,0);
 566           cluster->SetLabel(-9999,1);
 567           cluster->SetLabel(-9999,2);
 568
 569           cluster->AddTrackIndex(&idxTracks[iClusterROC*kNtrack]);
 570
 571         }
 572
 573         delete [] idxTracks;
 574
 575         // Write the cluster and reset the array
 576         WriteClusters(idet);
 577         ResetRecPoints();
 578
 579       } // loop: Sectors
 580     } // loop: Planes
 581   } // loop: Chambers
 582
 583   return kTRUE;
 584
 585 }
 586
 587 //_____________________________________________________________________________
 588 Double_t AliTRDclusterizerV1::GetCOG(Double_t signal[5])
 589 {
 590   //
 591   // Get COG position
 592   // Used for clusters with more than 3 pads - where LUT not applicable
 593   //
 594
 595   Double_t sum = signal[0]
 596                + signal[1]
 597                + signal[2]
 598                + signal[3]
 599                + signal[4];
 600
 601   Double_t res = (0.0 * (-signal[0] + signal[4])
 602                       + (-signal[1] + signal[3])) / sum;
 603
 604   return res;
 605
 606 }
 607
 608 //_____________________________________________________________________________
 609 Double_t AliTRDclusterizerV1::Unfold(Double_t eps, Int_t plane, Double_t *padSignal)
 610 {
 611   //
 612   // Method to unfold neighbouring maxima.
 613   // The charge ratio on the overlapping pad is calculated
 614   // until there is no more change within the range given by eps.
 615   // The resulting ratio is then returned to the calling method.
 616   //
 617
 618   AliTRDcalibDB *calibration = AliTRDcalibDB::Instance();
 619   if (!calibration) {
 620     AliError("No AliTRDcalibDB instance available\n");
 621     return kFALSE;
 622   }
 623
 624   Int_t   irc                = 0;
 625   Int_t   itStep             = 0;                 // Count iteration steps
 626
 627   Double_t ratio             = 0.5;               // Start value for ratio
 628   Double_t prevRatio         = 0.0;               // Store previous ratio
 629
 630   Double_t newLeftSignal[3]  = { 0.0, 0.0, 0.0 }; // Array to store left cluster signal
 631   Double_t newRightSignal[3] = { 0.0, 0.0, 0.0 }; // Array to store right cluster signal
 632   Double_t newSignal[3]      = { 0.0, 0.0, 0.0 };
 633
 634   // Start the iteration
 635   while ((TMath::Abs(prevRatio - ratio) > eps) && (itStep < 10)) {
 636
 637     itStep++;
 638     prevRatio = ratio;
 639
 640     // Cluster position according to charge ratio
 641     Double_t maxLeft  = (ratio*padSignal[2] - padSignal[0])
 642                       / (padSignal[0] + padSignal[1] + ratio*padSignal[2]);
 643     Double_t maxRight = (padSignal[4] - (1-ratio)*padSignal[2])
 644                       / ((1.0 - ratio)*padSignal[2] + padSignal[3] + padSignal[4]);
 645
 646     // Set cluster charge ratio
 647     irc = calibration->PadResponse(1.0,maxLeft ,plane,newSignal);
 648     Double_t ampLeft  = padSignal[1] / newSignal[1];
 649     irc = calibration->PadResponse(1.0,maxRight,plane,newSignal);
 650     Double_t ampRight = padSignal[3] / newSignal[1];
 651
 652     // Apply pad response to parameters
 653     irc = calibration->PadResponse(ampLeft ,maxLeft ,plane,newLeftSignal );
 654     irc = calibration->PadResponse(ampRight,maxRight,plane,newRightSignal);
 655
 656     // Calculate new overlapping ratio
 657     ratio = TMath::Min((Double_t)1.0,newLeftSignal[2] /
 658                                     (newLeftSignal[2] + newRightSignal[0]));
 659
 660   }
 661
 662   return ratio;
 663
 664 }
 665
 666 //_____________________________________________________________________________
 667 void AliTRDclusterizerV1::Transform(AliTRDdataArrayI *digitsIn
 668                                   , AliTRDdataArrayF *digitsOut
 669                                   , Int_t idet, Int_t nRowMax
 670                                   , Int_t nColMax, Int_t nTimeTotal
 671                                   , Float_t ADCthreshold)
 672 {
 673   //
 674   // Apply gain factor
 675   // Apply tail cancelation: Transform digitsIn to digitsOut
 676   //
 677
 678   Int_t iRow  = 0;
 679   Int_t iCol  = 0;
 680   Int_t iTime = 0;
 681
 682   AliTRDRecParam *recParam = AliTRDRecParam::Instance();
 683   if (!recParam) {
 684     AliError("No AliTRDRecParam instance available\n");
 685     return;
 686   }
 687   AliTRDcalibDB *calibration = AliTRDcalibDB::Instance();
 688   if (!calibration) {
 689     AliError("No AliTRDcalibDB instance available\n");
 690     return;
 691   }
 692
 693   Double_t *inADC  = new Double_t[nTimeTotal];  // ADC data before tail cancellation
 694   Double_t *outADC = new Double_t[nTimeTotal];  // ADC data after tail cancellation
 695
 696   AliDebug(1,Form("Tail cancellation (nExp = %d) for detector %d.\n"
 697                  ,recParam->GetTCnexp(),idet));
 698
 699   // Calibration object with chamber wise values for the gain factor
 700   const AliTRDCalDet *calGainFactorDet      = calibration->GetGainFactorDet();
 701   // Calibration object with pad wise values for the gain factor
 702   AliTRDCalROC       *calGainFactorROC      = calibration->GetGainFactorROC(idet);
 703   // Calibration value for chamber wise gain factors
 704   Float_t             calGainFactorDetValue = calGainFactorDet->GetValue(idet);
 705
 706   for (iRow  = 0; iRow  <  nRowMax;   iRow++ ) {
 707     for (iCol  = 0; iCol  <  nColMax;   iCol++ ) {
 708
 709       Float_t  calGainFactorROCValue = calGainFactorROC->GetValue(iCol,iRow);
 710       Double_t gain                  = calGainFactorDetValue
 711                                      * calGainFactorROCValue;
 712
 713       for (iTime = 0; iTime < nTimeTotal; iTime++) {
 714
 715         //
 716         // Add gain
 717         //
 718         inADC[iTime]   = digitsIn->GetDataUnchecked(iRow,iCol,iTime);
 719         inADC[iTime]  /= gain;
 720         outADC[iTime]  = inADC[iTime];
 721
 722       }
 723
 724       // Apply the tail cancelation via the digital filter
 725       if (recParam->TCOn()) {
 726         DeConvExp(inADC,outADC,nTimeTotal,recParam->GetTCnexp());
 727       }
 728
 729       for (iTime = 0; iTime < nTimeTotal; iTime++) {
 730
 731         // Store the amplitude of the digit if above threshold
 732         if (outADC[iTime] > ADCthreshold) {
 733           digitsOut->SetDataUnchecked(iRow,iCol,iTime,outADC[iTime]);
 734         }
 735
 736       }
 737
 738     }
 739   }
 740
 741   delete [] inADC;
 742   delete [] outADC;
 743
 744   return;
 745
 746 }
 747
 748 //_____________________________________________________________________________
 749 void AliTRDclusterizerV1::DeConvExp(Double_t *source, Double_t *target
 750                                   , Int_t n, Int_t nexp)
 751 {
 752   //
 753   // Tail cancellation by deconvolution for PASA v4 TRF
 754   //
 755
 756   Double_t rates[2];
 757   Double_t coefficients[2];
 758
 759   // Initialization (coefficient = alpha, rates = lambda)
 760   Double_t R1 = 1.0;
 761   Double_t R2 = 1.0;
 762   Double_t C1 = 0.5;
 763   Double_t C2 = 0.5;
 764
 765   if (nexp == 1) {   // 1 Exponentials
 766     R1 = 1.156;
 767     R2 = 0.130;
 768     C1 = 0.066;
 769     C2 = 0.000;
 770   }
 771   if (nexp == 2) {   // 2 Exponentials
 772     R1 = 1.156;
 773     R2 = 0.130;
 774     C1 = 0.114;
 775     C2 = 0.624;
 776   }
 777
 778   coefficients[0] = C1;
 779   coefficients[1] = C2;
 780
 781   Double_t Dt = 0.1;
 782
 783   rates[0] = TMath::Exp(-Dt/(R1));
 784   rates[1] = TMath::Exp(-Dt/(R2));
 785
 786   Int_t i = 0;
 787   Int_t k = 0;
 788
 789   Double_t reminder[2];
 790   Double_t correction;
 791   Double_t result;
 792
 793   // Attention: computation order is important
 794   correction = 0.0;
 795   for (k = 0; k < nexp; k++) {
 796     reminder[k] = 0.0;
 797   }
 798   for (i = 0; i < n; i++) {
 799     result    = (source[i] - correction);    // No rescaling
 800     target[i] = result;
 801
 802     for (k = 0; k < nexp; k++) {
 803       reminder[k] = rates[k] * (reminder[k] + coefficients[k] * result);
 804     }
 805     correction = 0.0;
 806     for (k = 0; k < nexp; k++) {
 807       correction += reminder[k];
 808     }
 809   }
 810
 811 }