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